Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N1/00—Sampling; Preparing specimens for investigation
  • G01N1/02—Devices for withdrawing samples
  • G01N1/10—Devices for withdrawing samples in the liquid or fluent state
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N1/00—Sampling; Preparing specimens for investigation
  • G01N1/02—Devices for withdrawing samples
  • G01N1/22—Devices for withdrawing samples in the gaseous state
  • G01N1/2202—Devices for withdrawing samples in the gaseous state involving separation of sample components during sampling
  • G01N1/2214—Devices for withdrawing samples in the gaseous state involving separation of sample components during sampling by sorption
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N1/00—Sampling; Preparing specimens for investigation
  • G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
  • G01N1/40—Concentrating samples
  • G01N1/405—Concentrating samples by adsorption or absorption
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N1/00—Sampling; Preparing specimens for investigation
  • G01N1/02—Devices for withdrawing samples
  • G01N1/10—Devices for withdrawing samples in the liquid or fluent state
  • G01N1/14—Suction devices, e.g. pumps; Ejector devices
  • G01N2001/1472—Devices not actuated by pressure difference
  • G01N2001/149—Capillaries; Sponges
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N1/00—Sampling; Preparing specimens for investigation
  • G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
  • G01N1/2813—Producing thin layers of samples on a substrate, e.g. smearing, spinning-on
  • G01N2001/2826—Collecting by adsorption or absorption
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N1/00—Sampling; Preparing specimens for investigation
  • G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
  • G01N1/38—Diluting, dispersing or mixing samples
  • G01N2001/383—Diluting, dispersing or mixing samples collecting and diluting in a flow of liquid

Definitions

• the invention relates to a method and a device for sampling trace components in gases, liquids, on pest bodies or in surface layers for the purpose of subsequent detection, identification or qualification.
• Traces that have been adsorptively enriched on gradient or sorption tubes from a gas can be removed using a relatively simple pneumatic system desorbed into a carrier gas by direct heating of the traces and fed to the gas detector.
• the analyzer is a gas chromatograph or a GC / MS coupling
• the sample must e.g. by means of an injection syringe through a septum for the evaporation of solvent and the trace component contained therein to the separation column entrance.
• an input head which can advantageously be used for discontinuous operation as a GC inlet system and which makes injection through a septum unnecessary (DE, P, 3009069.8 / 1980 and PCT / DE 81/00043/1981).
• the sample inlet takes place here, for example, in such a way that a solution to be investigated is successively applied to a contact membrane which has been flushed with carrier gas and is at a relatively low temperature T 1 , the solvent evaporating and the trace components of the solution to be analyzed in the contact membrane, which are concentrated almost without loss, only by increasing the temperature on T 2 get into the carrier gas.
• T 1 and T 2 adapted to the gas chromatographic mobility behavior of the trace component and the ⁇ rägergas misfluß- and the dead volume between the membrane and detector are low, then behind the contact membrane, in particular by rapid heating to the desorption temperature T 2, even with very small absolute amounts, which can be found in the small membrane volumes are sorbed, short-term high partial pressures are generated which exceed the partial pressures of the trace components in front of the membrane by orders of magnitude and improve the signal / noise ratio of the detector to the same extent.
• T 2 desorption temperature
• the object of the present invention is to improve the sensitivity of the known input head and to develop an even faster and gentler analysis method. This task is solved by the features contained in the characteristic of the device and process claim.
• the contact membrane is designed in such a way that it has a geometric shape that is as regular as possible, for example rectangular, square, five, six, eight and polygonal or circular, preferably the contact membrane is circular.
• the carrier gas is passed in such a way that it sweeps over the contact membrane from the side edges towards the center. This is achieved in that the carrier gas, preferably centrally disposed, delivery tube is guided ntaktmembran on the underside of a support plate for the contact membrane to the outer edges of the K o firstly of one and flows towards from there to the center of the contact membrane. For this it is necessary that a discharge line for the carrier gas is provided in the geometric center of the contact membrane. As can be seen from simple geometric considerations, the function is one
• the contact membrane is circular.
• the carrier gas flows from the circumference of the contact membrane to the center of the circle, where the discharge line for the carrier gas directly reaches the contact membrane.
• a collecting surface is applied to the contact membrane, which is suitable for the enrichment of trace components from gas, liquids and solids.
• This contact membrane must be such that it absorbs the components to be analyzed as selectively as possible.
• an inert tissue covered with silicone rubber for example, has proven to be expedient as the sorbing phase for the contact membrane.
• the quilt can also be made of glass fibers, filter paper or glass fiber filter paper, consist of metal sheet with sorbent coating or glass sheets with sorbent coating.
• the surface is appropriately adapted to the surface shape of the contact membrane, which ensures the largest possible common contact area.
• the application of the method and the device takes place in such a way that the collecting surface is exposed to the medium to be examined, for example the air, the water, the urine, blood, saliva, sweat sample, the skin of a test subject or patient, one homogenized food sample, a solvent extract, a coat of paint or another solid surface. Small portions of the trace component to be examined dissolve in the collecting area or its covering layer, which are proportional to the concentration present in the sample medium.
• the collecting surface can be designed as a filter disk on which suspended matter and others are suspended when air or liquids are sucked through. Separate particles. If the filter disc through which the flow passes is coated with a sorbing phase, gaseous trace components can also be enriched.
• the collecting surface is led to the contact membrane and heated. As a result, the collecting surface is regenerated in many applications, so that repeated use is possible. It is often expedient to rinse the collecting surface with distilled water after sampling the desorption of the trace component and to dry it mechanically using a swab.
• Devices can be used for a standardized, universal sampling and sample inlet quick method for the detection, identification and quantitative determination of trace components using GC, MS and GC / Design MS coupling.
• the surface or surface slide which can be examined for existing contaminants with the contact membrane of the input head, is advantageously designed such that it is suitable as a well-defined and standardized collecting surface for the enrichment of trace components from gases, liquids and solids.
• the temperatures must also be known in a manner familiar to the person skilled in the art, in addition to the collecting surface itself, which can be standardized, for example, with regard to material, surface, type of covering and covering layer thickness, sorption selectivity and capacity and heat capacity of collecting surface and contact membrane, exposure time and type of exposure, e.g. Gas / liquid at rest or flowing, powdered solid or with a smooth surface, as well as the contact time for desorption on the contact membrane must be defined as it is adequate for the required accuracy when correlating the measurement signal yield with the actual concentration or occupancy density in the medium under investigation .
• the contact membrane itself can also serve as a collection area.
• One (several) collecting surface (s) can be part of the input head and can be led to the contact membrane in alternating collecting phase / heating phase. Such an arrangement is particularly suitable as a detection probe for air monitoring. (Fig. 2)
• the input head is an evaluation system for thin layer chromatography (DC).
• the DC plate is brought to the contact membrane with the DC spot.
• the inventive method offers a convenient way of coupling the liquid (LC) and high pressure liquid chromatography (HPLG) with a mass spectrometer. The fractions eluting with the mobile phase can be individually concentrated on collecting areas and let into the ion source of the MS via the contact membrane.
• the collecting surface is capable of selective chemical sorption or the derivatization of certain components by means of special assignments.
• Basic components for example alkaloids, are selectively and reversibly sorbed by an acidic coating and alcohols are dehydrated when heating in the presence of dehydrating agents to give GC-compatible products.
• the derivatization for example the production of irimethylsilyl derivatives, can be conveniently carried out in the presence of a non-polar collecting surface, which preferentially sorbs the derivative when the reaction mixture cools because of its lower polarity.
• bacteria can be transferred to a collection area for the purpose of their identification on the basis of characteristic volatile constituents or pyrolysis products using a simple contact technique and analyzed according to the invention.
• Fig. 1 describes in cross-section and top view an embodiment of a suitable device with a contact membrane 1, which is backwashed by a carrier gas 2, and a collecting surface 3, which is shown in the embodiment as an inert tissue probe covered with a sorbing phase, for example silicone rubber.
• the collecting surface can also be a thin glass fiber filter paper, a sorbent coated metal sheet or a glass plate. It can have any surface shape, it is expediently adapted to the surface shape of the contact membrane, so that the largest possible contact area and a good heat and material exchange is guaranteed, i.e. the dead volume between the collecting surface and the detector 4 (not shown) should be small, so that high concentrations can be built up in the carrier gas.
• FIG. 3a shows a preferred embodiment of the collecting surface
• FIGS. 3b-3f show different possibilities for how samples to be examined can be applied to the collecting surface
• FIG. 3b shows the application of the contact membrane on a solid surface
• FIG. 3c and 3d the flow of gases onto or through the collecting surface
• FIG. 3e the dropping of liquid
• FIG. 3f the introduction of the collecting surface into a liquid.
• the invention offers a simple, universally applicable and extremely fast sampling and sample inlet method for qualitative and quantitative trace analysis by means of gas chromatography, mass spectrometry and GC / MS coupling.
• the method can be used to particular advantage in numerous routine applications in environmental analysis, residue and food analysis, Process and quality control, used in medical-clinical analysis, toxicology, microbiology, animal science, pharmacology, doping control, forensic technology and forensic medicine.
• Gas chromatographs, mass spectrometers and GC / MS couplings which are equipped with conventional injectors or inlet systems, can be converted with little effort using the device according to the invention.
• a suitably selectively sorbing, standardized collecting surface is exposed to the gas, the liquid or the solid for sampling, enrichment and possibly targeted chemical conversion of the trace component to be measured by contact under defined conditions and then for analysis of the sorbate and / or its reaction products on the heatable, Contact membrane of the input head of an analysis device flushed back by a carrier gas.
• the trace components which are thermally desorbing quantitatively from the collecting surface, reach the carrier gas in the course of a solution, diffusion and evaporation process through the contact membrane and are fed by the latter through a sample line or a gas chromatographic separation column to a gas analyzer, for example a mass spectrometer (MS).
• MS mass spectrometer

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• Life Sciences & Earth Sciences (AREA)
• Health & Medical Sciences (AREA)
• General Physics & Mathematics (AREA)
• Immunology (AREA)
• Chemical & Material Sciences (AREA)
• Analytical Chemistry (AREA)
• Biochemistry (AREA)
• General Health & Medical Sciences (AREA)
• Pathology (AREA)
• Physics & Mathematics (AREA)
• Hydrology & Water Resources (AREA)
• Engineering & Computer Science (AREA)
• Biomedical Technology (AREA)
• Molecular Biology (AREA)
• Sampling And Sample Adjustment (AREA)
• Other Investigation Or Analysis Of Materials By Electrical Means (AREA)
• Treatment Of Liquids With Adsorbents In General (AREA)

Applications Claiming Priority (2)

Publications (1)

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ID=6142365

Family Applications (1)

Country Status (5)

Cited By (1)

Families Citing this family (39)

Citations (5)

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• 1981
  • 1981-09-23 DE DE19813137765 patent/DE3137765A1/de active Granted
• 1982
  • 1982-09-22 EP EP82902900A patent/EP0089356B1/de not_active Expired
  • 1982-09-22 WO PCT/DE1982/000189 patent/WO1983001110A1/de not_active Ceased
  • 1982-09-22 US US06/504,688 patent/US4541268A/en not_active Expired - Lifetime
  • 1982-09-22 JP JP57502855A patent/JPS58501595A/ja active Pending

Patent Citations (5)

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