WO2021087467A2 - Analytical device - Google Patents

Abstract

In one aspect, a system to measure an environment includes a sampling device having a high aspect ratio, wherein the sampling device has a length substantially larger than any of its other cross-sectional dimensions, and the sampling device is flexible and includes at least one fluidic zone configured to hold a fluid containing an analyte; an applicator configured to introduce the sampling device into the environment containing the analyte; and a collector configured to hold the sampling device in a compact form and to retrieve the sampling device after the sampling device contacts the environment. In some embodiments, the system includes a sensing device to detect a property of the environment.

Description

ANALYTICAL DEVICE

RELATED APPLICATIONS

[0001] This application claims the benefit of priority to co-pending United States Provisional Application Serial No. 62/928,747, filed October 31, 2019, the contents of which is incorporated by reference herein.

COPYRIGHT NOTICE

[0002] This patent disclosure may contain material that is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure as it appears in the U.S. Patent and Trademark Office patent file or records, but otherwise reserves any and all copyright rights.

FIELD OF THE INVENTION

[0003] This application relates to an analytical device. In particular this application relates to measurement of an environment.

BACKGROUND

[0004] One of the prominent emerging challenges for the world in the coming decades will be food security — in 2050 the output from agriculture is predicted to be 50-70% lower than demand; currently the annual increase in output from agriculture is 1%, falling short of the needed annual increase of 3%. The increase is due to population growth, higher standards of living, and a need for more raw material from agriculture, e.g ., to replace fossil fuel as a stating material for the production of plastics). Climate change and unsustainable use of land and water resources are, in addition, projected to decrease the area of land suitable for cultivation by 30% until 2050.

[0005] Precision agriculture (PA) helps farmers to manage their crops and animals more efficiently based on, e.g., weather reports, satellite and drone imaging, soil tests, and historical data — all ideally used for computer-based multi-variate analysis, taking into account the whole operation of the farm to maximize its output. PA can increase the yields and quality of crops and pasture, and improve the efficiency of irrigation and fertilizer use, and decrease fertilizer run-off to waterways. PA commonly uses remote sensor technology to survey crops with a centimeter to meter resolution, including sensors for the visible, near Infra-Red (IR), and IR, and hyperspectral imaging. Two major problems must be addressed to realize the envisioned potential of PA: (1) Current imaging technology cannot remotely measure soil nutrient levels because soil is opaque to the used electromagnetic radiation, soil testing is therefore performed by proximal sensing, i.e., sampling soil, or using probes in contact with soil. Soil nutrients in the field varies in levels relevant for crop yield over distances of 1-25 meters (every 1-625 m²) — the current industry standard is one sample every 10,000-20,000 m² (1-2 samples every 5 acres), a sampling resolution that is 6 to 4000 times below the expected spatial variation. (2) The cost-effectiveness of current methods of soil testing, including materials, shipping, and labor, prohibits soil sampling at a high spatial density.

SUMMARY

[0006] In one aspect, a system to measure an environment includes a sampling device having a high aspect ratio, wherein the sampling device has a length substantially larger than any of its other cross-sectional dimensions, and the sampling device is flexible and includes at least one fluidic zone configured to hold a fluid containing an analyte; an applicator configured to introduce the sampling device into the environment containing the analyte; and a collector configured to hold the sampling device in a compact form and to retrieve the sampling device after the sampling device contacts the environment.

[0007] In some embodiments, the sampling device includes one or more fiber materials.

[0008] In some embodiments, the one or more fiber materials are woven, knitted, or twisted.

[0009] In some embodiments, the one or more fiber materials are selected from a group consisting of nylon, polypropylene, polyester, aramids, cotton, regenerated cotton, rayon, silk, wool, jute, Lyocel, ramie, hemp, and linen, and combinations thereof.

[0010] In some embodiments, the sampling device includes one or more polymer films.

[0011] In some embodiments, the one or more polymer films is selected from a group consisting of nitrocellulose, etylcellulose, metyl cellulose, acrylics, polycarbonate, butyrate, glycol-modified polyethylene terephthalate, low-density polyethylene, high density polyethylene, polyethylene terephthalate, polyvinyl chloride, polyester, and combinations thereof.

[0012] In some embodiments, the sampling device is porous.

[0013] In some embodiments, least one section of the sampling device is coated with a liquid barrier. [0014] In some embodiments, the liquid barrier is selected from a group consisting of wax, nail polish, varnish, epoxy compounds, rubbers, polysulfide rubber, epoxy casting resins, laminating resins, polysiloxanes, polyurethanes, thermoplastic elastomers, and combinations thereof.

[0015] In some embodiments, at least one section of the sampling device includes an analyte detection reagent.

[0016] In some embodiments, a portion of the section including the analyte detection reagent includes a transparent, impermeable coating.

[0017] In some embodiments, the analyte detection reagent is selected from the group consisting of pH indicators, Greiss reagent, heptamolybdate reagent, phenanththroline, sodium rhodizonate, carmine, Azomethine H and combinations thereof.

[0018] In some embodiments, the sampling device includes one or more electrode pairs, wherein each electrode pair includes a reference electrode and an ion-selective electrode. [0019] In some embodiments, the compact form is a roll of the sampling device.

[0020] In some embodiments, one or more of the applicator and the collector includes a reel.

[0021] In some embodiments, the applicator includes one or more blades configured to penetrate a surface of the environment and place the sampling device in the environment. [0022] In some embodiments, the system further includes one or more vehicles.

[0023] In some embodiments, one or more of the applicator and the collector are each connected to at least one of the one or more vehicles.

[0024] In some embodiments, the one or more of the applicator and the collector are connected to the same vehicle of the at least one of the one or more vehicles.

[0025] In some embodiments, the one or more of the applicator and the collector are each connected to a different vehicle of the one of the one or more vehicles.

[0026] In some embodiments, the system is stationary.

[0027] In some embodiments, the system includes a fixture to hold the system in place.

[0028] In some embodiments, the system is portable.

[0029] In some embodiments, the system includes a shovel-like portion and a structure for a foot to push the shovel-like portion into the environment.

[0030] In some embodiments, the system further includes a reservoir configured to apply a second fluid to the environment. [0031] In some embodiments, the second fluid is selected from a group consisting of water, extraction solutions, and combinations thereof.

[0032] In some embodiments, the system further includes a sensing device for detection.

[0033] In some embodiments, the sensing device is selected from the group consisting of a camera, a spectrophotometer, an electrochemical reader, an impedance meter, a potentiometer, and combinations thereof.

[0034] In some embodiments, the sensing device includes a pair of measuring electrodes configured to measure at least one of an electrical conductivity through the sampling device. [0035] In some embodiments, the pair of measuring electrodes configured to measure a potential difference between a reference electrode and an ion-selective electrode, wherein the reference electrode and the ion-selective electrode are disposed on the sampling device.

[0036] In some embodiments, the system further includes two or more calibration solutions, each calibration solution having a known concentration of the analyte.

[0037] In some embodiments, the system further includes a conditioning solution.

[0038] In some embodiments, the sensing device is configured to detect a color change of the sampling device.

[0039] In some embodiments, the sensing device is configured to detect water content, ionic content, pH, soil type, inorganic ions, small organic molecules, nutrients, or microorganisms.

[0040] In some embodiments, the environment includes at least oneor more of soil, compost, water, or manure.

[0041] In some embodiments, the environment is a soil selected from the group consisting of sand, clay, loam, peat, organic matter and combinations thereof.

[0042] In one aspect, a method of analyzing an analyte in an environment includes providing a sampling device having a high aspect ratio, wherein the sampling device has a length substantially larger than any of its other cross-sectional dimensions, and the sampling device is flexible and includes at least one fluidic zone configured to hold a fluid containing an analyte; introducing the sampling device into the environment containing an analyte via the applicator at a first time point; and receiving the sampling device from the environment via the collector at a second time point, wherein the collector is configured to hold the sampling device in a compact form.

[0043] In some embodiments, introducing the sampling device into the environment via the applicator includes unrolling the sampling device from an applicator reel. 4

ActiveUS 182706409v.4 [0044] In some embodiments, removing the sampling device from the environment via the collector includes rolling the sample device onto a collector reel.

[0045] In some embodiments, the method further includes moving the system through the environment.

[0046] In some embodiments, moving the system includes moving one or more of the applicator and the collector using a vehicle.

[0047] In some embodiments, the method further includes inserting a portion of the system into the environment.

[0048] In some embodiments, the method further includes penetrating a surface of the environment using a blade on the applicator and placing the sampling device in environment, [0049] In some embodiments, the method further includes applying a second fluid to the environment to release the analyte from the environment.

[0050] In some embodiments, the method further includes detecting properties of the environment.

[0051] In some embodiments, detecting properties of the environment includes analyzing the sampling device using a method selected from the group consisting of optical imaging, optical spectroscopy, mass-spectroscopy, electrochemical analysis, electrical impedance, electrical conductivity, and combinations thereof.

[0052] In some embodiments, detecting properties of the environment includes measuring the electrical conductivity through the sampling device.

[0053] In some embodiments, detecting properties of the environment includes detecting a color change of the sampling device.

[0054] In some embodiments, detecting properties of the environment includes measuring an electrical potential difference between a reference electrode and an ion-selective electrode. [0055] In some embodiments, the method further includes measuring the potential difference between a reference electrode and an ion selective electrode in two or more calibration solutions, each calibration solution having a known concentration of an analyte. [0056] In some embodiments, the method further includes contacting the ion-selective electrode with a conditioning solution.

[0057] In some embodiments, contacting the ion-selective electrode with a conditioning solution occurs when the ion-selective electrode no longer responds to a calibration solution having a known concentration of an analyte. 5

ActiveUS 182706409v.4 [0058] In some embodiments, contacting the ion-selective electrode occurs before measuring the potential difference between the reference electrode and the ion-selective electrode in the environment.

[0059] In some embodiments, the method further includes carrying the system by a person to a location.

[0060] In one aspect, a method of making a sampling device includes providing a water- permeable material having a high aspect ratio, wherein the water-permeable material has a length substantially larger than any of its other cross-sectional dimensions; and contacting a plurality of sections of the water-permeable material with a liquid barrier.

[0061] In some embodiments, contacting the plurality of sections of the water-permeable material with the liquid barrier includes contacting the sampling device with a stamp.

[0062] In some embodiments, the method further includes contacting one or more sections of the water permeable material with an analyte detection reagent, wherein the one or more sections were not contacted with the liquid barrier.

[0063] In some embodiments, contacting the one or more sections of the water permeable material with the analyte detection reagent includes contacting the sampling device with a stamp.

BRIEF DESCRIPTION OF THE DRAWINGS

[0064] FIG. 1 A shows fabrication and use of microfluidic sampling devices, according to certain embodiments.

[0065] FIG. IB shows a machine for automated reel-to-reel reading of color and redox potential in microfluidic sampling devices, according to certain embodiments.

[0066] FIG. 1C shows a tractor with on-the-go soil testing that give direct feedback to adjust fertilizer application, according to certain embodiments.

[0067] FIG. ID shows a photograph of a thread-based sampling device with different pH indicators that were imaged with the automated reel-to-reel machine, according to certain embodiments.

[0068] FIG. 2A shows a reel-to-reel system used to manufacture a sampling device, according to certain embodiments.

[0069] FIG. 2B shows stamps pushing a sampling device into baths of liquid, according to certain embodiments.

[0070] FIG. 2C shows moving the stamp to take a sampling device out of the baths of liquid, according to certain embodiments. 6

ActiveUS 182706409v.4 [0071] FIG. 2D shows rotation of reels to move the sampling device to the next section, according to certain embodiments.

[0072] FIG. 3 shows a seed tape planter modified to lay a sampling device in the ground, according to certain embodiments.

[0073] FIG. 4A shows a pH indicator on a sampling device with separate sections for color detection before addition of buffers, according to certain embodiments.

[0074] FIG. 4B shows a pH indicator on a sampling device with separate sections for color detection after addition of buffers, according to certain embodiments.

[0075] FIG. 5A shows a photograph of electrical current measurement, according to certain embodiments.

[0076] FIG. 5B shows a schematic of electrical current measurement, according to certain embodiments.

[0077] FIG. 6 shows measurement of electric current measured through a twisted cotton thread after it had absorbed salt water in wet sand, according to certain embodiments.

[0078] FIG. 7A shows the measurement of electric conductivity using an electrical conductivity probe in wet sand from a beach, according to certain embodiments.

[0079] FIG. 7B shows the measurement of electric current measured through a twisted cotton thread after it had absorbed salt water in wet sand from a beach, according to certain embodiments.

[0080] FIG. 8A shows measurement of electric current in wet soil taken from different areas measured by electrical conductivity probe, according to certain embodiments.

[0081] FIG. 8B shows measurement of electric current through a twisted cotton thread after it had absorbed liquid in wet soil that was taken from different areas, according to certain embodiments.

[0082] FIG. 9A shows a photograph of a reel-to-reel imaging machine, according to certain embodiments.

[0083] FIG. 9B shows a 3D-CAD schematic of a reel-to-reel imaging machine, according to certain embodiments.

[0084] FIG. 9C shows a photograph of the sampling device processing part mounted on an optical board with a designated post for camera mounting, according to certain embodiments.

[0085] FIG. 10 shows illumination of a sampling device with LEDS, according to certain embodiments. 7

ActiveUS 182706409v.4 [0086] FIG. 11 A shows photograph of a sampling device that was imaged automatically using the reel-to-reel imaging machine, according to certain embodiments.

[0087] FIG. 1 IB shows the red channel from an RBG image of a sampling device after image processing, including masking and conversion of the image to greyscale, according to certain embodiments.

[0088] FIG. llC shows the optical intensity profile across a sampling device, according to certain embodiments.

[0089] FIG. 12 shows an exemplary image of the console, according to certain embodiments.

[0090] FIG. 13 shows the color intensity of the red channel for a sampling device imaged with automated sampling device reader, according to certain embodiments.

[0091] FIG. 14 shows the color intensity of the RBG channels for a sampling device with a barcode imaged with automated sampling device reader, overlaid with the image of the sampling device, according to certain embodiments.

[0092] FIG 15 shows color intensity of the RBG channels for a sampling device with wax sections imaged with automated sampling device reader, overlaid with the image of the sampling device, according to certain embodiments.

[0093] FIG. 16 shows a schematic of a vehicle with an applicator and collectorfor on-the- go soil testing, according to certain embodiments.

[0094] FIG. 17 shows a schematic of a vehicle with an applicatorthat inserts a sampling device in the soil for another vehicle to collect, according to certain embodiments.

[0095] FIG. 18 shows a schematic of vehicle with a collector that only collects sampling devices from the soil, according to certain embodiments.

[0096] FIG. 19 shows a vehicle with a mechanical mechanism and a collector to collect a sampling device, according to certain embodiments.

[0097] FIG. 20 shows a stationary device for automated sampling of liquid with sampling devices that produces a colorimetric response that is imaged using an automated imaging machine, according to certain embodiments.

[0098] FIG. 21 shows a portable shovel-like sampling device, according to certain embodiments.

[0099] FIG. 22 shows a stationary device that allows for automated calibration, conditioning, and measurements using ion-selective electrodes, according to certain embodiments. 8

ActiveUS 182706409v.4 DETAILED DESCRIPTION

[0100] In one aspect, the system includes a sampling device having a high aspect ratio, wherein the sampling device has a length substantially larger than any of its other cross- sectional dimensions, and the sampling device is flexible and includes at least one fluidic zone configured to hold a fluid containing an analyte; an applicator configured to introduce the sampling device into an environment containing the analyte; and a collector configured to hold the sampling device in a compact form and to retrieve the sampling device after the sampling device contacts the environment.

[0101] In one aspect, the system enables a radical improvement in the cost-effectiveness of the testing of the properties of an environment, for example testing of an analyte in the environment, in the field at the desired resolution. This system (Large-scale microfluidics, i.e., LS-microfluidics) advances the whole process of environmental or soil testing by applying the principle of automated, serial reel-to-reel handling to the (i) production of microfluidic (microfluidic) devices, (ii) soil sampling, and (iii) analysis of the microfluidic devices.

[0102] In some embodiments, a large-scale microfluidics system allows cost-effective use of microfluidics over large areas with high spatial resolution. This system is realized by developing high-throughput (i) manufacturing of thread-based colorimetric and electrochemical microfluidic sampling devices, shown in FIG. 1 A, (ii) sampling with devices and, (iii) retrieval and read-out of these devices. The microfluidic sampling devices are designed to be able to analyze pH and important soil nutrients, including ammonium, nitrate, potassium and manganese ions, and phosphate (NPK). In some embodiments, shown in FIG. IB, a high-throughput, reel-to-reel reader reads and analyzes colorimetric and electrochemical devices on a sampling device. In some embodiments, shown in FIG. 1C, the microfluidic pH device is incorporated into a small scale vehicle with an applicator and collector for inserting the devices into the soil shown.

[0103] FIG. 1 A shows exemplary methods of making and using microfluidic sampling devices 100. In some embodiments, the cost of the thread-based sampling devices is kept low by using reel-to-reel manufacturing. In one embodiment, shown in FIG. 1 A, the sampling device includes a water-permeable material 101 ( e.g ., a thread) with a liquid barrier

102 (e.g., wax) applied at sections along the length of the sampling device. The exposed sections not coated with the liquid barrier form fluidic zones capable of holding liquid, e.g, by absorption or adsorption. In some embodiments, for colorimetric detection of analytes,

-9-

ActiveUS 182706409v.4 pH indicators are applied to the sections of the sampling device without the liquid barrier ( e.g ., fluidic zones) to form pH indicator zones 103. Next, a transparent coating 104 (e.g, nail polish) is applied to portions of the pH indicator zones. As a result, when the sampling device enters a wet environment (e.g, soil or water), liquid enters only areas of the pH indicator zones without the transparent coating. After the sampling device is extracted from the environment, the pH can be determined based on color change in the pH indicator zones. The cost of the sampling device is further reduced using low-cost materials described in FIG. 1 A. For example, as shown in FIG. 1 A, the microfluidic device that measure pH is made from nylon or cotton thread, wax (as a liquid barrier), transparent nail polish, polymer gels, and pH indicators. In some embodiments, the pH is measured because it changes the availability of soil nutrients, such as manganese and phosphate. In some embodiments, coating pH indicator zones with nail polish facilitates colorimetric read-out after sampling by preventing soil or other components of the environment from fouling the sampling device.

As a result, the color of the pH indicator zones can be imaged through the coating after the soil is brushed or rinsed-off (FIG. 1 A and ID). In some embodiments, a colorimetric reagent (e.g, a pH indicator) can be immobilized on the sampling device to avoid leakage of chemicals to the soil (similar to non-bleeding pH paper) using, e.g, l-Ethyl-3-(3- dimethylaminopropyl) carbodiimide-coupling reactions. In some embodiments, the immobilization of pH-indicators could make the sampling devices reusable (after washing and calibration).

[0104] FIG. IB shows an exemplary system 110 for automated reel-to-reel reading of color and redox potential in microfluidic sampling devices. In this embodiment, the system includes an applicator reel 111 that provides a sampling device 100 to a detection zone 120. In the embodiment shown in FIG. IB, the detection zone 120 includes a light source 121 and camera 122 for colorimetric measurements and an impedance meter 123 for electrical measurements of redox potential. After imaging, a collector reel 112 collects the sampling device 110. In some embodiments, rollers 113a, 113b guide the sampling device through the system. The rollers 113a, 113b can also act as electrodes for electrical measurement, e.g, to measure conductivity through the sampling device.

[0105] In some embodiments, shown in FIG. 1C, the system 110 is mounted on a vehicle 114 (e.g. a tractor) for on-the-go environmental testing that gives direct feedback (e.g, to adjust fertilizer application). In some embodiments, the system inserts the microfluidic sampling devices 110 into the environment using an applicator 111, and the position is 10

ActiveUS 182706409v.4 recorded with GPS. In some embodiments, the environment is wet soil with dissolved soil nutrients. The soil can be wet, for example, by rain, by adding water, or if appropriate, by adding extraction buffers for target analytes (e.g. soil nutrients). In some embodiments, the liquid enters the sampling device in the exposed section (sections without a transparent coating) and as the liquid wicks into the device, soil particles are filtered out before the liquid reaches the section or fluidic zone that assays the target analytes. The sampling device is then pulled out of the environment as one long thread and read in an imaging zone 120, for example, using a reel-to-reel machine as shown in FIG. IB. The sampling device is the collected at a collector 112. Fig. ID shows actual images produced with automated reel-to- reel RGB-imaging using the machine in Fig. IB. In some embodiments, the images are automatically analyzed with image processing software (e.g, a MATLAB program) that detects regions of changing color and the intensity of these regions.

[0106] In some embodiments, the system samples nutrients in environment such as soil, compost, water (e.g, for hydroponic cultivation), or manure. Nutrients detected in soil include, for example, ammonium, nitrate, potassium and manganese ions, and phosphate (NPK). In some embodiments, the soil includes sand, clay, loam, peat, or organic matter. In some embodiments, the device samples environmental contaminations (e.g, heavy metals, toxins). In some embodiments, the device searches for warfare agents (e.g, trace amounts of explosives from old mines)

[0107] In some embodiments, for a high spatial resolution survey of a field, sampling devices are deployed in a serpentine pattern over the field (at different depths if required). In some embodiments, measurements of soil nutrients directly in the field removes time-lag resulting in faster response to problems in crops. Measurement directly in the field also reduces the cost of sending samples to central facilities that often have weeks or months of backlogs during high season. In some embodiments, the system is mounted on a vehicle, for example, a tractor, to measure soil nutrients ‘on-the-go’ in the field, and the system simultaneously adjusts the amount of fertilizer spread from a variable rate spreader.

[0108] In some embodiments, the system described herein is applied to diagnostics in agriculture, forensics, veterinary medicine, healthcare, food safety, and armed forces.

A. Sampling Device

[0109] In some embodiments, the sampling device has a high aspect ratio and has a length substantially longer than any of its cross-sectional dimensions. In some embodiments, the sampling device is between about 0.1 m and about 16 km long and the cross-sectional 11

ActiveUS 182706409v.4 dimensions are between about 0.1mm and about 10mm. For, example the length of the sampling can depend on the size of a reel in the system. In some embodiments, the sampling device has a cross-section with a high aspect ratio ( e.g . a tape). In some embodiments, the sampling device has a cross-section with an aspect ratio close to one (e.g. a thread). In some embodiments, the sampling device has bending radius of curvature less than 100mm. For example, the sampling device is sufficiently flexible to be wrapped around a reel.

[0110] In some embodiments, the sampling device includes one or more fiber materials or threads. In some embodiments, the fiber is extruded. In other embodiments, the fiber is a natural fiber. In some embodiments, a fiber material is a yam of a same type of a material.

In some embodiments, the fiber material is woven, knitted or twisted from one or more fiber materials. In some embodiments, the fibers or threads are from the same materials. In some embodiments, the fibers or threads are from different material structures, which can be based on polymer materials, metal, or inorganic materials. In some embodiments, the fibers have a hydrophilic surface. In some embodiments, fibers have different chemical additives stored or immobilized in them. In some embodiments the sampling device is made of one or more fibers and includes a channel where fibers were removed, e.g. , to form a fluidic zone.

[0111] Non-limiting examples of fiber materials for a fiber device include nylon, polypropylene, polyester, aramids (including Kevlar® & Nomex®), cotton, regenerated cotton, rayon, silk, wool, jute, Lyocel, ramie, hemp, and linen and combinations thereof. [0112] In some embodiments, the sampling device includes a flexible tape or band. In some embodiments, the sampling device includes one or more polymer films or tapes. In some embodiments, the polymer films are stacked and/or bonded. In some embodiments, the polymer film includes channel structures e.g. , to form a fluidic zone. In some embodiments, the sampling device includes include plastic, porous materials, micro- or nano structures, such as filters, or nano- or micro-channels, multiple laminated materials, or electrically conductive layers or structures, e.g. , to form a fluidic zone. In some embodiments, micro- or nanostructures are embossed.

[0113] Non-limiting examples of polymer films include nitrocellulose, etylcellulose, metyl cellulose, Acrylic (polymethylmethacrylate), Lexan (polycarbonate), Butyrate (cellulose acetate butyrate), PETG (glycol-modified polyethylene terephthalate), low-density polyethylene, high Density Polyethylene, polyethylene terephthalate, PVC (polyvinyl chloride), polyester and combinations thereof. 12

ActiveUS 182706409v.4 [0114] In some embodiments, the sampling device can be porous. The sampling device can be nano- or microporous. In some embodiments, pores are hydrophilic and absorb liquids. In some embodiments, the sampling device includes a porous fiber. In some embodiments, porous sections of the sampling device form fluidic zones that can absorb liquid. In some embodiments, the surface of the material can have chemical treatment to absorb entities of interest ( e.g ., analyte, biologicals or organisms).

[0115] In some embodiments, the sampling device is based on interlocked hard material structures, such as chain made out of a metal or plastic material

[0116] In some embodiments, the sampling device can be any combination of the fibers, porous materials, tapes, or interlocked hard material structures described above.

[0117] In some embodiments, the sampling device is coated with an external sleeve which is porous or water impermeable. One example of an external sleeve is an electric cable having insulator around the cable. In some embodiments, the sampling device is coated with a liquid barrier. In some embodiments, sections along the length of the sampling device are coated with a liquid barrier. In some embodiments, the liquid barrier applicator is applied using a stamp. In some embodiments, the liquid barrier comprises a hydrophobic substance. Non limiting examples of liquid barriers include wax, nail polish, varnish, epoxy compounds, rubbers, polysulfide rubber, epoxy casting resins, laminating resins, polysiloxanes, polyurethanes, or thermoplastic elastomers such as thermoplastic styrenic block copolymers, thermoplastic polyolefmelastomers, thermoplastic vulcanizates, thermoplastic polyurethanes, thermoplastic copolyester, thermoplastic polyamides or combinations thereof. Non-limiting examples of commercial thermoplastic elastomer-products include CAWITON, THERMOLAST K, THERMOLAST M, Amitel, Hytrel, Dryflex, Mediprene, Kraton, Pibiflex, Sofprene, Laprene, CAWITON, THERMOLAST K, THERMOLAST M, Sofprene, Dryflex and Laprene. Laripur, Desmopan or Elastollan are non-limiting examples of thermoplastic polyurethanes (TPU). Additional non-limiting examples of thermoplastic elastomers include Sarlink, Santoprene, Termoton, Solprene, THERMOLAST V, Vegaprene, Forprene, For-Tec E, Engage, or Ninjaflex. Sections between the liquid barrier can form fluidic zones.

[0118] In some embodiments, the sampling device includes reagents for detection of analytes. In some embodiments, the sampling device includes one or more sections with pH indicators, e.g. in a pH indicator zone. Non-limiting examples of pH indicators include 13

ActiveUS 182706409v.4 Malachite green oxalate, Brilliant green, Eosin Y, Erythrosine B, Methyl green, Methyl violet, Cresol red, Crystal violet, Metanil yellow, m-Cresol purple, Thymol blue, 22'2", 4,4' Pentamethoxy-triphenylcarbinol, Eosin B, Quinaldine red, 2,4-Dinitrophenol, Dimethyl yellow, Bromophenol blue, Congo red, Methyl orange, Bromocresol green, Alizarin red, Methyl red, Chlorophenol red, Litmus, Bromocresol, 4-Nitrophenol, Bromoxylenol blue, Bromothymol blue, Phenol red, Cresol red, 3-Nitrophenol, Neutral red, 1-Naphtholphthalein, m-Cresol purple, Thymol blue, Phenolphthalein, Thymolphthalein, Alkali blue, Alizarin yellow, Indigo carmine, and Titan yellow. In some embodiments, the reagent includes a chemical such as Griess reagent to test for nitrate and nitrite, ammonium heptamolybdate reagent to test for phosphate, phenanththroline to test for iron(III), sodium rhodizonate (to test for lead(II), carmine or Azomethine H to test for bor(III). In some embodiments, the sampling device includes an electrochemical device for analyte detection. Non-limiting examples of electrochemical devices include ion selective electrodes and other devices designed to do the following electrochemical measurements: e.g ., cyclic voltammetry, linear sweep voltammetry, differential pulse voltammetry, square wave voltammetry, electrochemical impedance spectroscopy and combinations thereof.

[0119] In some embodiments the sampling device includes one or more electrodes. For example, the sampling device can include a plurality of pairs of electrodes. In some embodiments, each pair of electrodes includes a reference electrode and an ion-selective electrode. In some embodiments, a thread based reference electrode is made from a thread that has been covered with conductive ink. For example, the thread can then be painted with a solution containing o-nitrophenyl octyl ether (o-NPOE), poly(vinyl chloride) (PVC), and the ionic liquid 1 -octyl-3 -methylimidazolium bis(trifluoromethylsulfonyl)imide (MeOctlm TFSI) to form a ionic-liquid-based reference electrode. An PVB/NaCl -based reference electrode can be constructed by painting with a paste containing Polyvinylbutyral (PVB) in a solution in methanol with dispersed Ag, AgCl and NaCl. The solvents are allowed to evaporate from the paste to form the membranes. Ion-selective electrodes are described in more detail below. In some embodiments, a sampling device with electrodes can be used for potentiometry.

B. System Components

[0120] In some embodiments, the system includes a sampling device, an applicator configured to introduce the sampling device into an environment containing the analyte, and 14

ActiveUS 182706409v.4 a collector configured to hold the sampling device in a compact form and to retrieve the sampling device after the sampling device contacts the environment.

[0121] In some embodiments, the applicator includes one or more dispensers for the sampling device. For example, the applicator can include a reel and the reel is configured to store a majority of the sampling device, before the sampling device is placed into the environment. In some embodiments, the reel has dimensions between about 10cm and about 5m. In some embodiments, a control device regulates the dispenser based on the sampling device output as one of its inputs. In some embodiments, a portion of the sampling device is situated adjacent to or through the applicator unit. In some embodiments, the applicator has one or more blades (similar to a plough) configured to penetrate the surface of the environment ( e.g . soil or terrain) and place the sampling device in the environment (e.g, with a portion of the sampling device under the surface of the environment).

[0122] In some embodiments, the applicator is configured to remove or modify part of the sampling device stored in the applicator, before the sampling device is placed into the environment. For example, the applicator can remove or penetrate a liquid barrier (e.g., plastic foil or aluminum foil) to a compartment containing an assay dissolved in a liquid in the sampling device. In this example, the liquid barrier prevents evaporation of the liquid in the time period between fabrication of the sampling device and use in the field. Assays that are already dissolved in liquid when used in the field have the following benefits: (1) the process of dissolution of a dry compound into a liquid often takes time (e.g, seconds to minutes). (2) an assay that is already dissolved in a liquid will therefore be likely to have a more rapid response to an analyte compared to an assay that first has to dissolve in a liquid sample that is wicked into the device. In addition, some assays do not dissolve in water or water of standard pH (e.g, the pH of the environment); it is therefore beneficial to have the assay dissolved inside the device in an organic or polar solvent, or in a solvent of an acidic or basic pH. For example, some pH indicators dissolve poorly at neutral pH, but dissolve well in acidic or basic solutions. As another example, other pH indicators dissolve well in alcohols such as ethanol. In some embodiments, the applicator includes one or more reservoirs, storing one or more solutions; and one or more solutions are configured to be brought into contact with part of the sampling device before the sampling device is placed into the environment. In some embodiments, these solutions can remove or penetrate a liquid barrier. 15

ActiveUS 182706409v.4 [0123] In some embodiments, the collector comprises a reel configured to store a majority of the sampling device after the sampling device is removed from the environment. In some embodiments, the reel has dimensions between about 10cm and about 5m. In some embodiments, the collector includes one or more materials and the collector is configured to apply the one or more materials around the sampling device, before the sampling device is stored inside of the collector. In some embodiments, the one or more materials applied around of the sampling device hinders the material transport to and from the sampling device. For example, the applied material could be a plastic or metallic coating or film that protects the sample ( e.g ., from solvent evaporation or chemical or biological contamination) inside the sampling device before it is analyzed, for example in a central laboratory. In addition, the film or coating could also protect the sampling device from cross contamination with other parts of the thread when in is stored in the reel/collectors (e.g., the different parts of the thread/sampling device will touch each other when stored on a reel). In some embodiments, the collector includes one or more reservoirs, storing one or more solutions; and one or more solutions are configured to be brought into the contact with part of the sampling device after the sampling device is removed from the environment. In some embodiments, these solutions help protect the sample before the sample is analyzed [0124] In some embodiments, the system includes one or more vehicles. In some embodiments, the applicator, the connector, or both are connected to one of the vehicles. The applicator and collector can alternatively be connected to the same or different vehicles. Non-limiting examples of vehicles include tractors, cars, trucks, and combinations thereof. [0125] In some embodiments the system is portable and can be transported by a human. For example, a portable system can be transported and then inserted into the environment. In some embodiments, a portable system includes a shaft and a housing for applicator and collector reels. In these embodiments, the sampling device is fed from a applicator, down the shaft to contact the environment, and up to a collector. In some embodiments, a portable system includes a detector zone to detect analytes on the sampling device after the sampling device passes through the environment. In some embodiments, a portable system includes shovel-like portion and a step for a foot to push the shovel-like portion into the environment (e.g. into the ground).

[0126] In some embodiments, the system is stationary. In some embodiments, a stationary system is inserted into the environment. In some embodiments, a stationary system includes a shaft and a housing for applicator and collector reels. In these 16

ActiveUS 182706409v.4 embodiments, the sampling device is fed from a applicator, down the shaft to contact the environment, and up to a collector. In some embodiments, a stationary system includes a detector zone to detect analytes on the sampling device after the sampling device passes through the environment. In some embodiments, a stationary system includes a fixture that holds the sampler in place.

[0127] In some embodiments, the system applies a liquid or fluidto the environment containing the analyte at the location where the location where the sampling device contacts the environment, for example using the applicator. In some embodiments, the liquid dissolves the analyte before the environment is sampled using the sampling device. In some embodiments, the liquid includes components that release the analyte from the environment. For example, if soil is dry, liquid can be added to wet the soil. In another example, if the analyte is tightly bound to the soil, liquid can be added to release or extract the analyte from the soil. In some embodiments, the liquid is stored in a reservoir that is either on the applicator or separate from the applicator. In some embodiments, the liquid is connected to the applicator via a tube. Non-limiting examples of such liquids include water, a solution that helps to extract the analytes from the matrix ( e.g ., soil particles) of the sample, and combinations thereof.

[0128] In some embodiments, the system includes one or more positioning device configured to record the location in the environment and the distance of the sampling device, for example using GPS.

C. Methods to Measure Properties of the Environment

[0129] In some embodiments, the system includes a detection zone to detect properties of the environment. In some embodiments, the system measures or detects water content, ionic content, pH, soil type, inorganic ions, small organic molecules, nutrients, or microorganisms. Non-limiting examples of nutrients detected in soil include ammonium, nitrate, nitrite, potassium ions, phosphate, zinc ions, magnesium ions, calcium ions, chlorine ions, sulfur ions, iron ions, lead ions, cadmium ions, cupper, boron ions, and manganese ions, and combinations thereof. In some embodiments, the system samples biological entities (microbiology, microbiome, infectious agents, invasive species). In these embodiments, the system can be used for DNA analysis or cell culture methods. Non-limiting examples of detection methods include optical detection (direct colorimetric, spectroscopic (IR/UV), fluorescence, luminescence) or electrical detection (conductance, electrochemistry, potentiometry). In alternate embodiments, the system performs collection and storage, 17

ActiveUS 182706409v.4 without onsite analysis. In these embodiments, the sampling device is transported to a laboratory with instruments for analysis such as mass spectrometry, flame ionization, and molecular biology assays.

[0130] In some embodiments, the system includes a sensing device for detection. In some embodiments, the collector includes a sensing device. Non-limiting examples of sensing devices includes a camera, a spectrophotometer, an electrochemical reader, an impedance meter, a potentiometer, and combinations thereof. In some embodiments, the system analyzes the sampling device to measure or detect an analyte of interest. For example, analyzing the samples can be based on optical imaging, optical spectroscopy, mass- spectroscopy, electrochemical analysis, electrical impedance, electrical conductivity, and combinations thereof.

[0131] In some embodiments, the sampling device further includes distance marks along the device. These distance marks serve as unique identifiers of the location on the sampling device. In some embodiments, the distance marks are defined by optical color (i.e. in the visible spectrum), for example, using a dark pigment or dye ( e.g ., by a pen or marker). In some embodiments, the distance marks are defined by changes in electrical conductivity that are induced, e.g., by applying inks and chemicals that are electrically conductive. Distance markers can also form a barcode.

1. Electrical Conductivity Measurement

[0132] In some embodiments, detection includes measurement of electrical conductivity through the sampling device. In some embodiments, the electrical conductivity of a sampling device that was passed through the environment is measured to determine the water content, ionic content, or soil type. In some embodiments, the type of soil is determined by investigating the contribution to the conductivity of soil moisture, water conductivity, and inherent soil conductivity (e.g, clay conducts better than loam, which conducts better than sand). In some embodiments, the structure of sampling devices for measuring the electrical conductivity of soil is simple. For example, in one embodiment, a porous thread without any devices on it is used to sample the liquid in the soil. In other embodiments, the microfluidic device could have increased capability by increasing the complexity of the method and device. For example, electrical conductivity can measured using two electrodes in contact with the sampling device and an impedance meter. Below are three steps listed to that enable deconvolution of the effect of water content, ionic content, and soil type ways on the electrical conductivity measured in a sampling device. 18

ActiveUS 182706409v.4 [0133] In a first embodiment, electrical conductivity of a simple porous sampling device (with no impermeable sections) is measured after sampling of liquid in the soil by putting the sampling device in contact with two electrodes with a known spacing to measure the electrical conductivity in the sampling device using an impedance meter. In this embodiment, the electrical conductivity of the device would depend on the amount of liquid adsorbed, the ionic species and their concentration in the sampled liquid, and the type of soil that the sample was taken from.

[0134] In a second embodiment, a layer of a material impermeable to liquid ( e.g ., nail polish or wax) is added to the surface of short sections of the sampling device, leaving areas of sampling device exposed (e.g., fluidic zones). In this embodiment, the soil particles are filtered out as the liquid sample wicks through the sampling device and the electrical conductivity of the sections (the short regions of the sampling device covered with impermeable material) of the sampling device would depend on the amount of liquid adsorbed and the ionic species in the sample.

[0135] In a third embodiment, a device with impermeable material on short sections of the sampling device would be used to sample the soil and the electrical conductivity of the sampling device is measured in the field (at the point of measurement). In this embodiment, the sampling device would be dried to remove all liquid. Then, a controlled amount of water would then be added to saturate the sampling device with liquid, taking care to not wash out any dissolved sample out in the sampling device, and the electrical conductivity of different sections of the sampling device would be measured again. The electrical conductivity of the sampling device in this embodiment would mostly depend on the ionic content of the sample that was absorbed into the sampling device. One benefit of this method is that it removes dependence on water content. With these three methods, the water content, ionic content, and soil type in the liquid sample could be approximated.

2. Colorimetric Detection

[0136] In some embodiments, detection includes optical colorimetric detection. In these embodiments, the sampling device includes sections with different pH indicators that change color depending on the pH. Non-limiting examples of pH indicators include Malachite green oxalate, Brilliant green, Eosin Y, Erythrosine B, Methyl green, Methyl violet, Cresol red, Crystal violet, Metanil yellow, m-Cresol purple, Thymol blue, 22'2", 4,4' Pentamethoxy- triphenylcarbinol, Eosin B, Quinaldine red, 2,4-Dinitrophenol, Dimethyl yellow, Bromophenol blue, Congo red, Methyl orange, Bromocresol green, Alizarin red, Methyl red, 19

ActiveUS 182706409v.4 Chlorophenol red, Litmus, Bromocresol, 4-Nitrophenol, Bromoxylenol blue, Bromothymol blue, Phenol red, Cresol red, 3-Nitrophenol, Neutral red, 1-Naphtholphthalein, m-Cresol purple, Thymol blue, Phenolphthalein, Thymolphthalein, Alkali blue, Alizarin yellow, Indigo carmine, and Titan yellow. Alternatively, other indicators for other analytes can be used such as Griess reagent to test for nitrate and nitrite, ammonium heptamolybdate reagent to test for phosphate, phenanththroline to test for iron(III), sodium rhodizonate (to test for lead(II), carmine or Azomethine H to test for bor(III). In one embodiment, the sampling device includes a water-permeable material ( e.g ., a thread) with a liquid barrier 102 (e.g, wax) applied at sections along the length of the sampling device. In this embodiment, pH indicators are applied to the sections of the sampling device without a liquid barrier. Non limiting examples of pH indicators include thymol blue, methyl orange, bromocreosol green, chlorophoenol red, bromothymol blue, phenolphthalein. Next, a transparent, impermeable coating (e.g, nail polish) is applied to portions of the pH indicator sections. As a result, when the sampling device enters a wet environment (e.g, soil), liquid enters only areas of the pH indicator sections without the transparent coating. After the sampling device is extracted from the environment, the pH can be determined based on color change in the pH indicator sections. In some embodiments, coating of nail polish facilitates colorimetric read-out after sampling by preventing soil from fouling the sampling device. As a result, the color can be imaged through the coating after the soil is brushed or rinsed-off In some embodiments, a colorimetric reagent (e.g, a pH indicator) can be immobilized on the sampling device to avoid leakage of chemicals to the soil (similar to non-bleeding pH paper) using, e.g., 1-Ethyl- 3-(3-dimethylaminopropyl) carbodiimide-coupling reactions. In some embodiments, the immobilization of pH-indicators could make the sampling devices reusable (after washing and calibration). Additional non-limiting examples of colorimetric assays include a chemical such as Griess reagent to test for nitrate and nitrite, ammonium heptamolybdate reagent to test for phosphate, phenanththroline to test for iron(III), sodium rhodizonate (to test for lead(II), carmine or Azomethine Hto test for bor(III)

1. Ion-selective Electrode

[0137] In some embodiments, the analyte detector includes an ion-selective electrode. In some embodiments, an ion-selective electrode enables potentiometric sensing of ions. Ion- selective membranes are described in WO 2019/094966, the contents of which are incorporated by reference. In some embodiments, an ion-based electrode includes a thread containing a plurality of fibers and a conductive coating. Exemplary conductive coatings 20

ActiveUS 182706409v.4 include Ag/AgCl, Ag/Ag2S, LaF3 (doped with europium fluoride EuF2), conductive polymers, inks made from carbon materials (carbon graphite, carbon nanotubes, carbon black, and other forms of carbon), inks made of conducting polymers (example polype- ethyl enediox-y thiophene) poly(styrenesulfonate), and other types of conducting polymers known to the state of the art), inks made of metal nanoparticles, and the like. Some exemplary conducting polymer includes poly(3,4-ethylenediox-ythiophene)- poly(styrenesulfonate) ("PEDOT:PSS"), polythiophene, polypyrrole, and the like.

[0138] In some embodiments, the ion-selective electrode further includes an ion-selective membrane. In some embodiments, the ion-selective membrane includes a hydrophobic membrane, a receptor that binds the target ion ( e.g ., an ionophore), and a hydrophobic ion used as a counterion to the target ion. Some suitable cations and anions that can be sensed include g⁺, Zn⁺, Cd

the like.

[0139] In some embodiments, detection of a target ion is measured using a reference electrode, for example an Ag/AgCl electrode. In some embodiments, a potentiometric cell includes an ion-selective electrode and a reference electrode. When the ion-selective electrode and reference electrode are contacted with an aqueous solution (e.g. in the environment), the potential difference between the two electrodes can be measured and used to measure the concentration of an analyte in the solution.

[0140] In some embodiments, the sampling device includes a plurality of pairs of ion- selective electrodes and reference electrodes. For example, conductive electrodes (e.g., metal electrodes) can be used to measure the electrical potential between an ion-selective electrode and a reference electrode when the pair of electrodes is in a solution. In some embodiments, the sampling device is painted with a conductive ink to create an electrical connection between the reference electrode or ion-selective electrode and the measuring electrodes. Non-limiting examples of conductive ink include inks containing carbon black, graphite, carbon nanotubes, poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), copper, silver, and combinations thereof.

[0141] In some embodiments, two or more calibration solutions of known analyte concentration can be used to calibrate electrical potential measurements with the concentration of a target analyte. For example, the electrical potential difference between a reference electrode and an ion-selective electrode can be measured in a first calibration 21

ActiveUS 182706409v.4 solution using a measuring electrode and in a second calibration solution using a measuring electrode. By measuring the electrical potential in two or more calibration solutions with known concentration of an analyte, a calibration curve can be generated to convert an electrical potential measurement into an analyte concentration. After calibration, the electrode pair can be used to measure the concentration of a target analyte in an environment, for example in a hydroponic nutrient solution.

[0142] In some embodiments, ion-selective membranes of the ion-selective electrodes are depleted of conditioning ions over time. Ion-selective membranes can be depleted over a time period of hours to days, depending on the concentration of the sample and the duration of measurements. For example a membrane is depleted by ion exchange more quickly if the sample has a high salt concentration or if measurements are taken continuously. For example, ion-selective membranes can be depleted over the course of hours or days of measurement. When an ion-selective membrane is depleted, the sampling device can be fed backwards to and contacted with a conditioning solution to condition the ion-selective membrane, e.g. by exchanging with conditioning ions. A conditioning solution can include, for example, potassium ions (e.g, in a potassium chloride solution). In some embodiments, the potential difference of the reference electrode and ion-sensitive electrode can be measured to identify the timepoint when the ion-selective electrode is sufficiently conditioned. For example conditioning can take from minutes to hours, depending on how depleted the membrane is. After conditioning, the portion of the sampling device with the conditioned ion-selective electrode can be returned to the environment to continue measurement. In this way, a sampling device with ion-selective electrodes can be used continuously or reused.

D. Methods of Manufacturing

[0143] In some embodiments, shown in FIGs. 2A-2D, a sampling device can be manufactured using a reel-to-reel manufacturing system 230. FIG 2A shows a reel-to-reel system to manufature a microfluidic sampling device. The system includes a circular input reel 231 with a first radius and a circular output reel 232 with a second radius, with a sampling device material 233 (e.g, a thread) mounted on the input reel and the ouput reel. In some embodiments, the system includes a drive mechanism for driving at least one of the reels to advance the sampling device material. The system includes applicator units 234 (e.g. stamps) between the reels and above the microfluidic sampling device material, as well as units of liquid baths between the reels and below the sampling device material. The baths include (1) liquid barrier 235 (e.g. wax or other polymer for impermeable liquid barrier 22

ActiveUS 182706409v.4 sections) or liquid compontents of the assay 236 (e.g. analyte detection reagents or pH indicators). In some embodiments, the system includes multiple applicator units, wherein the liquid barrier applicator and analyte detector applicator within each applicator unit are ordered in the same direction such that no liquid barrier applicator is adjacent to a liquid barrier applicator of another applicator unit.

[0144] As shown in FIG. 2B, the applicator units 234 are moved down to push the liquid sampling device material into the baths 235, 236 of liquid. The liquid sampling device material 233 is then immersed in the liquid baths to absorb the liquid on the surface or within the porous structure of the sampling device. As shown in FIG. 2C, the applicator unit 234 is moved up to take the liquid sampling device material 233 out of the baths 235, 236 of liquid. Finally, as shown in FIG. 2D, the reels 231, 232 rotate to move the liquid samplng device material 233 to the next section without microfluidic devices to create the next unit of microfluidic devices. The steps shown in FIGs. 2B-2C are repeated. In some embodiments, the liquid sampling device material is advanced through the manufacturing system, and a liquid barrier and analyte detector are applied to distinct portions of the sampling device material.

I. EXAMPLES

[0145] Certain embodiments will now be described in the following non-limiting examples.

A. Modified Seed Tape Planter

[0146] FIG. 3 shows a seed tape planter modified to lay a sampling device in the ground, instead of seed tape. The planter includes a rotating drum that can holds the thread with or without sampling devices. In this example, the drum 341 is loaded with twisted nylon (ACE) without sampling devices. FIG. 3 also shows the point 342 where the thread exits the seed planter, into the soil. The dashed white line indicates the level of the soil surface relative to the planter. The soil depth at which the thread is released can be adjusted.

B. pH Indicator

[0147] FIGs. 4A-4B show a pH indicator on a sampling device with separate sections for color detection of pH indicators in different pH ranges. The pH indicator sampling device includes a twisted cotton (Wellington, unwashed) thread 401 with 1 cm wide wax sections 402 (dark areas) interspaced with 1 cm wide non-waxed sections. The non-waxed areas were soaked in pH indicator 403 solution and let dry before the threads were dipped in 3 different 23

ActiveUS 182706409v.4 pH buffers: Tris (pH 8.18), phosphate-buffered saline (pH 7.43), and acetate (pH 4.53). FIG. 4A shows the pH indicator before addition of buffers. The numbers indicate the pH ranges of each indicator. FIG. 4B shows the pH indicator after addition of buffers. The names indicate the name of each indicator (thymol blue, methyl orange, bromocreosol green, chlorophoenol red, bromothymol blue, phenolphthalein). The rectangles encircle areas of the thread that had especially large changes in color after being dipped in pH-buffers.

C. Measurement of Electric Current

[0148] FIGs. 5A-5B show methods of measuring electric current in a sampling device. FIG. 5A shows a photograph of electrical current in a thread-based sampling device 500 measured between the two metal screws 524a, 524b (electrodes) that contact a thread-based sampling device. In this example, the tubes are used as weights. FIG. 5A shows a schematic of a reel-to-reel system for electrical current measurement. In FIG. 5B, the sampling device 500 is provided by an applicator reel 511 and passes through a measuring zone 620 before being collected by collector reel 512. The current through the sampling device is measured using two electrodes 524a, 524b.

[0149] FIG 6. shows electric conductivity measured through twisted cotton thread that was buried for a few minutes in sand (Sigma Aldrich) with different amounts of amounts of added sodium chloride. The measurements were performed at different degrees of water saturation of the soil (100%, 75%, 50%, 25%). 100% water saturation indicates liquid water visible on top of soil. Error bars depict the standard deviation (n=12).

[0150] FIGs. 7A-7B show electric conductivity measured in wet sand taken from a beach at different distances from the water. FIG. 7A shows measurements from an electrical conductivity probe (gold standard). FIG. 7B shows measurements from twisted cotton thread sampling device that was buried for a few minutes in the sand at each location. The thread and the conductivity probe measured the same pattern of conductivity difference for the different sand samples. Error bars depict the standard deviation (n=12).

[0151] FIGs. 8A-8B show electric current measured in wet soil taken from different areas (indicated by street name) in Cambridge, MA. FIG. 8A shows measurements from an electrical conductivity probe (gold standard). FIG. 8B shows measurements from twisted cotton thread sampling device that was buried for a few minutes in soil in each area. The thread and the conductivity probe measured a similar pattern of conductivity difference for the different soil samples. Error bars depict the standard deviation (n=12).

D. Optical Measurement 24

ActiveUS 182706409v.4 [0152] FIGs. 9A-9C show a reel-to-reel sampling machine for optical measurement. FIG. 8A shows a photograph of the whole machine. FIG. 9B shows a 3D-CAD schematic of the sampling machine. FIG. 9C shows a photograph of the sampling device processing part that is mounted on an optical board with a designated post for camera mounting.

[0153] In some embodiments, shown in FIG. 10, the sampling device is illuminated with LEDs along its length for even illumination.

[0154] FIGs. 11 A-l 1C show optical images of a sampling device. FIG. 11 A shows a test photograph of a sampling device. In this photograph, the sampling device has high contrast with the background, so the sampling device is easy to differentiate. FIG. 1 IB shows the masked black and white intensity of sampling device. The photographs were shot with 24mm lens on an APS C sensor camera (Canon EOS 550D). FIG. 11C shows the horizontal average intensity profile across the sampling device. In this profile, oscillations are thread grooves. There is some intensity variation over entire field of view which can be calibrated and normalized. If the setup is calibrated, this profile does not vary. The set up can be calibrated by dipping devices in different solutions of known concentrations of an analyte, imaging the devices, and quantifying the average color intensity to create a standard curve.

E. Controller Firmware

[0155] Controller firmware allows for changing of relevant parameters for optical measurement using a reel-to-reel system. For example, there are 7 commands, and each command is a single capital letter. When started, controller sends out the command list to a console. The console acknowledges receiving all commands ( e.g ., RUN, HALT, L=10, etc.). If running, the console shows the number of segments that have been scanned already. FIG. 12 shows an exemplary image of the console.

Table 1. Commands of firmware

25

ActiveUS 182706409v.4

F. Analysis of Optical Images

[0156] FIG. 13 shows the color intensity of the red channel of a thread-based sampling device imaged with automated sampling device reader and analyzed with an automated program, for example, a MATLAB program to determine the color intensity of the sampling device in the region that contains color. In this image, the color absorbed into the sampling device was McCormick Red Food Color.

[0157] FIG. 14 shows the color intensity of the RBG channels of a thread-based sampling device imaged with automated sampling device reader and analyzed with an automated MATLAB program that provides an automated calculation of average color intensity in the regions of the sampling device that contain color. The color intensity is overlaid with an image of the sampling device. The sampling device was marked with a permanent black marker pen to form a barcode on the sampling device that can be used to identify a specific section of the sampling device. For example, the barcode can be positioned before or after the section.

[0158] FIG. 15 shows the color intensity of the RBG channels of a thread-based sampling device imaged with automated sampling device reader and analyzed with an automated MATLAB program that provides an automated calculation of average color intensity in the regions of the sampling device that contain color along the length of the sampling device.

The color intensity is overlaid with an image of the sampling device. The sampling device has sections soaked in wax (white sections that separate the sections that are soaked in different pH indicators, in this case chlorophenol red (100-2500 px) and bromocreosol purple (3500-4000 px). The pH indicators in the different sections change color at different pH and hence the pH of the soil can be found by observing the color of the different sections (similar to pH paper).

G. Vehicles for Sampling

[0159] FIG. 16 shows a schematic of a machine for on-the-go soil testing using electric conductivity measurements, or colorimetric- or electrochemical-microfluidic devices. This vehicle inserts the sampling device, collects the sampling device, and analyzes the sampling device. The results can be used as direct feedback to adjust fertilizer application (fertilizer 26

ActiveUS 182706409v.4 spreader not included in schematic). The system includes a vehicle body A, wheels B, reels C, Q to hold sampling devices E, a lever D with wheels that guide the sampling devices, a plough F shaped to guide the sampling devices into the soil, holders G that connect mechanism H and plough F, a mechanical mechanisms H that brings plough F up and down in soil, lever I connecting body A and mechanism H, lever I with wheel J that keeps a constant distance between soil and mechanism H, box M where sampling devices are characterized, camera N, rollers P that guide the sampling device and are used to make electrical conductivity and electrochemistry measurements in sampling device. The depth at which the sampling device is dispensed can be adjusted by moving plough F up and down using mechanism H. The machine moves over soil surface K, and soil bulk L, with large grey arrow showing the direction of movement of vehicle. In some embodiments, the oscillatory (up and down) dispensing of sampling device at different soil depths is done to measure soil nutrients at different soil depths. In this machine, the sampling device is provided on roller C, guided by the wheels on lever D, and inserted into the soil via the plough F. The mechanical mechanism H moves the plough F up and down so that the sampling device samples the soil at different depths. The sample is the collected using the wheels on the levers D at the back of the device and guided to the box M for characterization before being collected on reel Q. In box M, a camera N provides colorimetric detection, while the rollers P act as electrodes for conductivity measurements.

[0160] FIG. 17 shows a schematic of machine that inserts the sampling device into the soil for another machine to collect later. This machine includes a vehicle body A, wheels B, reel C holding sampling device E, lever D with wheels that guide the sampling device, a plough F shaped type that guides the sampling device into the soil, holders G that connect mechanism H and plough F, mechanical mechanisms H that brings plough F up and down in soil, lever I that connects body A and mechanism H, lever I with wheel J that keep a constant distance between soil surface K and mechanism H. The depth at which the sampling device is dispensed can be adjusted by moving plough F up and down using mechanism H. The machine moves over soil surface K, and soil bulk L, with large grey arrow showing the direction of movement of vehicle. In this machine, the sampling device is provided on reel C, guided by the wheels on lever D, and inserted into the soil via the plough F. The mechanical mechanism H moves the plough F up and down so that the sampling device samples the soil at different depths. The sampling devices can then be retrieved using another machine ( e.g ., the machine in FIG. 18). 27

ActiveUS 182706409v.4 [0161] FIG. 18 shows a schematic of machine that collects sampling devices that were inserted in the soil by another machine ( e.g . the machine in FIG. 17). This machine includes a vehicle body, wheels B, reel C for collecting the sampling device I, a box D where sampling devices are characterized, rollers F that guide the sampling device and are used to make electrical conductivity and electrochemistry measurements ((+)-pole) in the sampling device, rollers G that guide the sampling device and are used to make electrical conductivity and electrochemistry measurements ((-)-pole) in the sampling device. Lever H with wheels guide sampling device I. The machine moves over soil surface J, with large grey arrow showing the direction of movement of the vehicle. In this machine, the sampling device I is removed from the soil and guided by the wheels on lever H to the box D for characterization. In box D, a camera N provides colorimetric detection, while the rollers F, G act as electrodes for conductivity measurements. Then, the sampling device is collected on the reel C.

[0162] FIG. 19 shows a more robust mechanical mechanism to collect a sampling device. This machine only collects sampling devices from the soil. This machine includes a vehicle body A, wheels B, reels C holding the sampling device, box D where microfluidic devices are characterized, rollers F that guide sampling device I and are used to make electrical conductivity and electrochemistry measurements ((+)-pole) in the sampling device, rollers G that guide the sampling device and are used to make electrical conductivity and electrochemistry measurements ((-)-pole) in the sampling device. Lever H with wheels guides the sampling device, J-Soil surface. Since the lever H is close the soil, this component can control the extraction of the sampling device more effectively. For this reason, the machine is less likely to run over the sampling device if the sampling device becomes stuck in the soil. The machine moves over soil surface J, with large grey arrow showing the direction of movement of vehicle. In this machine, the sampling device I is removed from the soil and guided by the wheels on lever H to the box D for characterization. In box D, a camera E provides colorimetric detection, while the rollers F, G act as electrodes for conductivity measurements. Then, the sampling device is collected on the reel C.

H. Stationary Devices for Sampling

[0163] FIG. 20 shows a cross-sectional view of a stationary device 2010 for automated sampling and analysis of liquid samples using thread or strip-based sampling devices. The stationary device can be deployed for sampling the environment, or in chemical or biological processes in industry. This stationary device includes a shaft 2014, a fixture 2015 that holds the device in place, and a housing 2016 for an applicator reel 2011 and a collector reel 2012. 28

ActiveUS 182706409v.4 The sampling device 2000 is fed for several steps by the reels to enable testing of a new liquid sample. The sampling device 2000 is provided by the applicator reel 2011 and moved down the shaft 2014. As shown in the inset, the sampling device 2000 is exposed to the environment at the bottom of the shaft 2014. In the inset, pH indicator sections 2003a,

2003b, 2003c will absorb liquid from the environment, while sections coated with a liquid barrier 2002a, 2002b will not absorb liquid. The detection zone 2020 includes a camera 2022 and light sources 2021a, 2021b to detect changes in color of the pH indicator sections.

I. Portable Devices for Sampling

[0164] FIG. 21 shows a portable shovel-like device for point testing of soil on foot, or from vehicle (Cross-sectional view). The sampling device is feed one or several steps by the reels to enable testing of a new soil sample. The portable device includes a shaft 2114, a step 2118 for a foot to push the shove-like device into the environment ( e.g ., the soil), and a housing 2016 for an applicator reel 2111 and a collector reel 2112. The sampling device 2100 is fed for several steps by the reels to enable testing of a new liquid sample. The sampling device 2100 is provided by the applicator reel 2111 and moved down the shaft 2114. As shown in the inset, the sampling device 2100 is exposed to the environment at the bottom of the shaft 2014. In the inset, pH indicator sections 2103a, 2103b, 2103c will absorb liquid in the environment, while sections coated in a liquid barrier 2102a, 2102b will not absorb liquid. The detection zone 2120 includes a camera 2122 and light sources 2121a, 2021b to detect changes in color of the pH indicator sections. In this example the device also includes a container 2118 with a liquid such as water or extraction buffer that is delivered to the location where the sampling device is exposed to the environment using a tube 2119. The liquid can be added to dissolve analytes or release analytes from the soil to allow absorption by the sampling device. This container can be carried in a back-pack or on a vehicle.

J. Stationary Device with Ion-selective Electrodes

[0165] FIG. 22 shows a stationary device with ion-selective electrodes. This automated stationary applicator that measure analytes with thread-based ion selective electrodes (ISE). The system enables automated calibration, conditioning, and measurements of analytes using ISEs, e.g., in hydroponic cultivation, as illustrated in FIG. 22. The different parts of the system are not drawn to scale. The system 2210 in FIG. 22 includes an applicator reel 2211 that provides a sampling device 2200 and a collector reel 2212 that collects the sampling device 2200. The system also includes a series of calibration 2243a, 2243b and conditioning 29

ActiveUS 182706409v.4 2244 solutions. In this system, the sampling device includes pairs of ISEs 2241a, 2241b, 2241c, 224 Id and reference electrodes 2242a, 2242b, 2242c, 2242d.

[0166] The automated stationary applicator in FIG. 22 allows ISEs to measure analytes for extended amounts ( e.g ., months to years) of time without human intervention, saving time and money on labor. The stationary applicator performs automated conditioning and calibration of the ISEs. The sampling device with the ISEs is feed between the two dispensers 2211, 2212 (e.g., reels) and through the different solutions using two electrical motors, each located at the center each reel. New ISEs come preconditioned and are calibrated in one or more calibration solutions, e.g., solutions of different but known concentrations of analytes. In the system in FIG. 22, there is a first calibration solution 2243a, a second calibration solution 2243b, and a conditioning solution 2244. In each solution, the electrical potential is measured between the reference (ref) electrode and the ISE. The electrical potential is measured between each pair of thread-guides 2245a, 2245b, 2245c, 2245d (marked with the electrical polarity ‘+’ and of the electrical connection) that is located above each solution. The thread-guides rotate to minimize the mechanical stress on the reference electrodes and the ISEs. The thread-guides are made of a conductive materials, such as a metal. Each thread-guide is electrically connected to the reference electrode or ISE that is located just below through conductive ink painted onto the sampling device, e.g, ink that contains electrically conductive carbon black.

[0167] For example, as shown in FIG. 22, the electrical potential difference between reference electrode 2242d and ISE 2241d is measured in the first calibration solution 2243a using thread guide pair 2245d. Similarly, the electrical potential difference between reference electrode 2242c and ISE 2241c is measured in the second calibration solution 2243b using thread guide pair 2245c. By measuring the electrical potential in two or more calibration solutions with known concentration of an analyte, the electrical potential measurement can be converted to an analyte concentration. The electrical potential difference between reference electrode 2242b and ISE 2241b is measured in the conditioning solution 2244 using thread guide pair 2245b.

[0168] After calibration, the ISEs is moved into the nutrient solution 2245 to perform continuous measurements of the analyte. As shown in FIG. 22, the electrical potential difference between electrode 2242a and ISE 2241a in the nutrient solution 2245 is measured using thread guide pair 2245a. After hours to days of measurements the ISEs are depleted of conditioning-ions (e.g. potassium ions) and the ISE will not respond properly to changes in 30

ActiveUS 182706409v.4 concentration of the analyte in the environment. This point can be determined when the ISE no longer respond or responds poorly to known ion concentration ( e.g . in the calibration solutions). In this scenario, the ISE can be fed backwards to the conditioning solution 2244 were the membrane of the ISE is again exchanged with conditioning-ions. After conditioning, the ISE is calibrated in the calibration solutions 2244 and then moved to the nutrient solution 2245 again to perform measurements in the nutrient solution. After some time (e.g., days to weeks) the performance of the ISE might degenerate to the point where calibration and conditioning is not sufficient for the ISE to perform accurate measurements. Whenever an ISE that actively measures an analyte breaks, or fails calibration, or becomes fouled with biological/chemical buildup, the ISE can be replaced with a new ISE from the dispenser 2211 to perform measurements.

K. Large Area Sampling Device

[0169] In some embodiments, the system includes a machine for placing the large area sampling device (LASD) into the soil. In some embodiments, the machine processes the LASD, while placing it, e.g., removing protective components of the device. In some embodiments, the machine is used, for instance, to add liquid or activate chemicals.

[0170] In some embodiments, the system includes a delay between when the LASD is placed into the environment and it when the LASD collected from the environment. The delay can be short, and the same machine collects the LASD from the soil. Alternatively, the delay can be long and different machine collects the LASD either concurrently or in future time point. In some embodiments, a method for large area spatial characterization of the environment includes providing a system for larger area chemical or biological sampling of the environment; moving the applicator in the environment to be characterized; and dispensing the sampling device into the environment; moving the collector in the environment to collect the sampling device from the environment; providing a delay between the dispensing and collecting of the sampling device.

[0171] In some the embodiments the system processes the sampling device directly by adding a reagent, adding a buffer, or making measurements described above.

[0172] In some embodiments, the system makes decisions to apply fertilizer, plant seeds, pesticides or microorganism based on the results of analyzing the LASD.

[0173] In some embodiments, the system stores the LASD. In some embodiments, storing involves preservation steps, which can include adding reagent(s), involves 31

ActiveUS 182706409v.4 encapsulation into a sleeve or between protective tapes, or includes drying, fixation, infusion and curing or a protective matrix.

[0174] In some embodiments, the system measures length of placed and/or collected LASD and synchronize it with geographic location. Location can be attributed to position acquired with positioning system, such as GPS. Additionally, in some embodiments, a LASD includes distance marks along the device. In some embodiments, distance marks are colorimetric, conductivity based or include integrated circuit. In some embodiments, distance marks are used to synchronize the distance of the LAMD and increase the positioning accuracy of sampling.

[0175] In some embodiments, a method of deposition of one or more substances to the environment based on the feedback from spatial sensing is described, including providing a system of any one or more embodiments as disclosed herein for larger area chemical or biological sampling of the environment with a sensing device; moving the applicator in the environment to be characterized; and dispensing the sampling device into the environment; moving the collector in the environment to collect the sampling device from the environment; providing a delay between the dispensing and collecting of the sampling device providing an dispenser of one or more substances utilizing the sensing device to acquire a signal; and further utilizing a control device, adapted and configured to use the acquired signal from the sensing device to regulate the dispense of one or more substances to deposit variable amount of substance to the environment.

[0176] It will be appreciated that while one or more particular materials or steps have been shown and described for purposes of explanation, the materials or steps can be varied in certain respects, or materials or steps can be combined, while still obtaining the desired outcome. Additionally, modifications to the disclosed embodiment and the invention as claimed are possible and within the scope of this disclosed invention. 32

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Claims

1. A system to measure an environment comprising: a sampling device having a high aspect ratio, wherein the sampling device has a length substantially larger than any of its other cross-sectional dimensions, and the sampling device is flexible and comprises at least one fluidic zone configured to hold a fluid containing an analyte; an applicator configured to introduce the sampling device into the environment containing the analyte; and a collector configured to hold the sampling device in a compact form and to retrieve the sampling device after the sampling device contacts the environment.

2. The system of claim 1, wherein the sampling device comprises one or more fiber materials.

3. The system of claim 2, wherein the one or more fiber materials are woven, knitted, or twisted.

4. The system of claim 2, wherein the one or more fiber materials are selected from a group consisting of nylon, polypropylene, polyester, aramids, cotton, regenerated cotton, rayon, silk, wool, jute, Lyocel, ramie, hemp, and linen, and combinations thereof.

5. The system of claim 1, wherein the sampling device comprises one or more polymer films.

6. The system of claim 5, wherein the one or more polymer films is selected from a group consisting of nitrocellulose, etylcellulose, metyl cellulose, acrylics, polycarbonate, butyrate, glycol-modified polyethylene terephthalate, low-density polyethylene, high density polyethylene, polyethylene terephthalate, polyvinyl chloride, polyester, and combinations thereof.

7. The system of claim 1, wherein the sampling device is porous. 33

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8. The system of claim 1, wherein at least one section of the sampling device is coated with a liquid barrier.

9. The system of claim 8, wherein the liquid barrier is selected from a group consisting of wax, nail polish, varnish, epoxy compounds, rubbers, poly sulfide rubber, epoxy casting resins, laminating resins, polysiloxanes, polyurethanes, thermoplastic elastomers, and combinations thereof.

10. The system of claim 1, wherein at least one section of the sampling device comprises an analyte detection reagent.

11. The system of claim 10, wherein a portion of the section comprising the analyte detection reagent comprises a transparent, impermeable coating.

12. The system of claim 10, wherein the analyte detection reagent is selected from the group consisting of pH indicators, Greiss reagent, heptamolybdate reagent, phenanththroline, sodium rhodizonate, carmine, Azomethine H and combinations thereof.

13. The system of claim 1, wherein the sampling device comprises one or more electrode pairs, wherein each electrode pair comprises a reference electrode and an ion-selective electrode.

14. The system of claim 1, wherein the compact form is a roll of the sampling device.

15. The system of claim 1, wherein one or more of the applicator and the collector comprises a reel.

16. The system of claim 1, wherein the applicator comprises one or more blades configured to penetrate a surface of the environment and place the sampling device in the environment.

17. The system of claim 1, further comprising one or more vehicles.

18. The system of claim 17, wherein one or more of the applicator and the collector are each connected to at least one of the one or more vehicles.

19. The system of claim 17, wherein the one or more of the applicator and the collector are connected to the same vehicle of the at least one of the one or more vehicles. 34

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20. The system of claim 17, wherein the one or more of the applicator and the collector are each connected to a different vehicle of the one of the one or more vehicles.

21. The system of claim 1, wherein the system is stationary.

22. The system of claim 21, wherein the system comprises a fixture to hold the system in place.

23. The system of claim 1, wherein the system is portable.

24. The system of claim 23, wherein the system comprises a shovel-like portion and a structure for a foot to push the shovel-like portion into the environment.

25. The system of claim 1, further comprises a reservoir configured to apply a second fluid to the environment.

26. The system of claim 25, wherein the second fluid is selected from a group consisting of water, extraction solutions, and combinations thereof.

27. The system of claim 1, further comprising a sensing device for detection.

28. The system of claim 27, wherein the sensing device is selected from the group consisting of a camera, a spectrophotometer, an electrochemical reader, an impedance meter, a potentiometer, and combinations thereof.

29. The system of claim 27, wherein the sensing device comprises a pair of measuring electrodes configured to measure at least one of an electrical conductivity through the sampling device.

30. The system of claim 29, wherein the pair of measuring electrodes configured to measure a potential difference between a reference electrode and an ion-selective electrode, wherein the reference electrode and the ion-selective electrode are disposed on the sampling device.

31. The system of claim 30, further comprising two or more calibration solutions, each calibration solution having a known concentration of the analyte.

32. The system of claim 30, further comprising a conditioning solution. 35

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33. The system of claim 27, wherein the sensing device is configured to detect a color change of the sampling device.

34. The system of claim 27, wherein the sensing device is configured to detect water content, ionic content, pH, soil type, inorganic ions, small organic molecules, nutrients, or microorganisms.

35. The system of claim 1, wherein the environment comprises at least one or more of soil, compost, water, or manure.

36. The system of claim 35, wherein the environment is a soil selected from the group consisting of sand, clay, loam, peat, organic matter, and combinations thereof.

37. A method of analyzing an analyte in an environment comprising providing a sampling device having a high aspect ratio, wherein the sampling device has a length substantially larger than any of its other cross-sectional dimensions, and the sampling device is flexible and comprises at least one fluidic zone configured to hold a fluid containing an analyte; introducing the sampling device into the environment containing an analyte via the applicator at a first time point; and receiving the sampling device from the environment via the collector at a second time point, wherein the collector is configured to hold the sampling device in a compact form.

38. The method of claim 37, wherein introducing the sampling device into the environment via the applicator comprises unrolling the sampling device from an applicator reel.

39. The method of claim 37, wherein removing the sampling device from the environment via the collector comprises rolling the sample device onto a collector reel.

40. The method of claim 37, further comprising moving the system through the environment.

41. The method of claim 40, wherein moving the system comprises moving one or more of the applicator and the collector using a vehicle. 36

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42. The method of claim 37, further comprising inserting a portion of the system into the environment.

43. The method of claim 37, further comprising penetrating a surface of the environment using a blade on the applicator and placing the sampling device in environment,

44. The method of claim 37, further comprising applying a second fluid to the environment to release the analyte from the environment.

45. The method of claim 37, further comprising detecting properties of the environment.

46. The method of claim 45, wherein detecting properties of the environment comprises analyzing the sampling device using a method selected from the group consisting of optical imaging, optical spectroscopy, mass-spectroscopy, electrochemical analysis, electrical impedance, electrical conductivity, and combinations thereof.

47. The method of claim 45, wherein detecting properties of the environment comprises measuring the electrical conductivity through the sampling device.

48. The method of claim 45, wherein detecting properties of the environment comprises detecting a color change of the sampling device.

49. The method of claim 45, wherein detecting properties of the environment comprises measuring an electrical potential difference between a reference electrode and an ion- selective electrode.

50. The method of claim 49, further comprising measuring the potential difference between a reference electrode and an ion selective electrode in two or more calibration solutions, each calibration solution having a known concentration of an analyte.

51. The method of claim 49, further comprising contacting the ion-selective electrode with a conditioning solution.

52. The method of claim 51, wherein contacting the ion-selective electrode with a conditioning solution occurs when the ion-selective electrode no longer responds to a calibration solution having a known concentration of an analyte. 37

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53. The method of claim 51, wherein contacting the ion-selective electrode occurs before measuring the potential difference between the reference electrode and the ion-selective electrode in the environment.

54. The system of claim 37, further comprising carrying the system by a person to a location.

55. A method of making a sampling device, comprising providing a water-permeable material having a high aspect ratio, wherein the water- permeable material has a length substantially larger than any of its other cross-sectional dimensions; and contacting a plurality of sections of the water-permeable material with a liquid barrier.

56. The method of claim 55, wherein contacting the plurality of sections of the water- permeable material with the liquid barrier comprises contacting the sampling device with a stamp.

57. The method of claim 56, further comprising contacting one or more sections of the water permeable material with an analyte detection reagent, wherein the one or more sections were not contacted with the liquid barrier.

58. The method of claim 57, wherein contacting the one or more sections of the water permeable material with the analyte detection reagent comprises contacting the sampling device with a stamp. 38

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