TW200914822A - Sensor system based on compound with solubility depending on analyte concentration - Google Patents

Abstract

A biochemical sensing device for measuring an analyte level, e.g., for in vivo applications. An exemplary device includes an electrode (12), a power supply (18) connected to the electrode, and a compound/polymer coating (14) on the electrode. The compound/polymer is soluble in a solution, and its rate of solubility is dependent on an analyte-related property of the solution, e.g., the solution pH. The biochemical sensing device can further include an electrical switch (16) in the connection between the power supply and the electrode. The biochemical sensing device can further include a data processor (22) connected to the power supply (18), and a data memory component (24) connected to the data processor. A process for measuring analyte-related property of a solution is also provided. The process includes providing an electrode coated with a compound/polymer, wherein the compound/polymer has an analyte-dependent solubility profile, exposing the compound/polymer coated electrode to the solution, measuring the conductance at the electrode as a function of time, and correlating the rate of conductance to the solubility of the compound/polymer to determine the pH of the solution.

Description

200914822 IX. DESCRIPTION OF THE INVENTION: FIELD OF THE INVENTION The present invention relates to a method for determining the concentration of an analyte present in a liquid, and more particularly to a use or inclusion of a variable solubility based on the concentration of the analyte. Compound sensing system. [Prior Art] The concentration of an analyte in a biological fluid can be determined either by quantifying a specific chemical interaction of a pair of target analytes or by converting an analyte into a physical parameter of measurable f). For example, the pH of a fluid can be determined by titration (chemical reaction) or using a pH meter that converts the H+ concentration to a potential. A conventional pH meter uses two glass electrodes: the indicator electrode and the reference electrode. When the two electrodes are immersed in a solution, a small chemical battery is formed. The potential developed is related to the two electrodes. The reaction is caused by the exchange of glass ions and the h+ of the solution on the surface of the swollen film in the ion exchange controlled by the H+ concentration in the two solutions. The conventional pH sensing technique can be reduced to a certain size to determine the in vivo. pH and telemetry report data.另一个 Another PH sensing technology is based on the use of an ion-sensitive field effect transistor (ISFET). In an ISFET, a U+ sensitive buffer coating is applied to the gate. Therefore, the voltage drop across the drain and source becomes a function of the H+ concentration at which the gate is exposed. A 1?11 sensor based on 181^1 can be made into a small volume. Experiments to ISFET pH sensors are commercially available and are generally more expensive than conventional glass electrode pH sensors. Conventional glass-based pH sensing techniques cannot actually be scaled down to the size of electronic pills. Both conventional and ISFET-based pH sensors 130412.doc 200914822 require calibration and reference electrodes to complicate their use. The pH accuracy as measured by an ISFET pH sensor can be negatively affected by ions other than 11+ such as salt. At present, ISFET costs are relatively high. In addition, the absolute accuracy and reproducibility of all current PH sensors depends on accurate and timely calibration, which makes their deployment expensive and cumbersome. For the immediate delivery of the gastrointestinal (GI) tract, the PH sensor must be operated in vivo during transport in the gastrointestinal tract, and (iv) a very small volume, while the absolute accuracy is less stringent, and recyclability is not a necessary condition. In addition to the pH' other analytes such as proteins, amino acids, glucose, enzymes and their analogs, the concentration is also of great diagnostic value. Although the above analytes can be assayed in vitro using laboratory equipment, practical in vivo methods and/or devices for determining protein or enzyme concentrations are not commercially available. In the biomedical field, in vivo measurements provide immediate and local information. However, the in vivo method is required to be a biological phase so that the process and by-products of the method do not interfere with the natural operation of the biological system. In addition, any device and/or component introduced into the living body must be small enough to accommodate the biosensing area due to the size of the organ. Despite attempts to date, there is still a need for effective methods and systems for determining analyte concentrations, particularly in biomedical applications, such as in vivo applications. These and other needs are met by the methods and systems disclosed herein. SUMMARY OF THE INVENTION A biochemical sensing device and method for biochemical assays is provided in accordance with the present disclosure. The disclosed sensing devices and methods can be used in vivo to determine the analyte content of 130412.doc 200914822. For example, the disclosed sensing devices and methods can be used to determine H+ concentrations (i.e., pH), proteins, amino acids, glucose, enzymes, and other analytes of interest.

In an exemplary embodiment of the present disclosure, a sensing device is provided that includes an electrode (12), a power source (丨8) coupled to the electrode, and a compound coating (14) on the electrode. The compound is soluble in an analyte solution, the rate of solubility of which depends on the concentration of the analyte, thereby allowing the analyte content to be quantified in a particular environment. The biosensing device can further comprise a source and an electrode Electrical switch (16) at the junction. The biochemical sensing device can further include a data processor (22) coupled to the power source (18), and a data memory component (24) coupled to the data processor. A method of determining the analyte concentration of a solution is also provided. In an exemplary embodiment of the invention, the disclosed method comprises providing an electrode coated with a compound having a solubility profile associated with an analyte concentration, exposing the coated electrode to a solution towel, determining The impedance rate acts as a function of time and correlates the impedance rate with the solubility of the compound to determine the analyte concentration of the solution. - An example of a biochemical sensing device according to the present disclosure is a pH sensing skirt. Further advantageous features, functions, and applications of the disclosed sensing devices and methods will be clarified by the following description. [Embodiment] The system and the methods disclosed herein will be described with reference to the accompanying drawings. The present invention provides a biochemical sensing system that is small in size and economical to manufacture, and that is easy to deploy and has a phase of 130412.doc 200914822. Exemplary of the disclosed biochemical sensor system & only examples include at least one electrode coated with a compound (e.g., a polymer) wherein the solubility of the compound is related to the concentration of the biochemical analyte. When the electrode coated with the compound/polymer is exposed to a solution, the conductance impedance between the electrodes varies as a function of the solubility of the compound/polymer in solution. To the extent that the compound/polymer is dissolved in the solution, the sample solution fills the void created by dissolving the compound/polymer:

Since the compound/polymer is a poor conductor compared to the solution, the dissolution of the chemical on the electrode and the dissolution of the σ coating results in an increase in conductivity between the electrodes. Conductivity change rate further depends on compound/polymer properties and actual analyte concentration of the sample solution. Materials suitable for coating electrodes according to the present disclosure include exhibiting solubility depending on the biochemical material of interest (eg, η+ concentration) (Immediately, the protein of the amino acid, the flavonoids, the enzymes, and other analytes) concentration of the material σ material for the exemplary materials of the coated electrode according to the present disclosure includes the display of - and ρΗ Related dissolution rate polymers, such as EUDRAGIT acrylic polymers manufactured by egussa GmbH, and polymers exhibiting dissolution rates associated with the presence of colonic enzymes, such as azo polymerization used by yme plc A (Cambridge, UK) The polymer has been used as a coating for coating on a musical tablet that is transported from a table. However, according to the present invention, the use of materials having the properties mentioned is advantageously used as Electrode coating. Methods The systems and methods disclosed herein with reference to pH are disclosed in more detail for the purposes of illustration. 130412.doc 200914822 has a wide range of applicability, which will be apparent to those skilled in the art, including the practice of various analytes. Thus, in an exemplary embodiment of the present disclosure, the system is included at a higher pH. Electrode coating compound/polymer that does not dissolve before the value, and therefore the conductance between the electrodes does not increase until the sample solution has a pH above this threshold. If the pH of the sample solution is higher than the application The threshold, then the conductance between the electrodes will advantageously increase proportionally with the difference between the actual pH of the sample and the threshold pH of the polymer. Furthermore, if the compound/polymer coated on the electrode is below pH in solution 2 If the threshold does not dissolve before, the conductance between the electrodes does not increase until the solution has a pH below this threshold. If the pH of the solution is below the threshold, the conductance will be based on the actual pH of the solution and the threshold. The difference increases proportionally. Therefore, by monitoring the rate of conductance change between the electrodes covered with the compound/polymer, the pH limit or the actual pH can be derived. In the pH-dependent theoretical pH sensor of pH, the conductance between each pair of electrodes is measured as a function of time, and the rate of change in conductance is used to derive the pH of the solution. A unique advantage of such a pH sensor system is not required. Calibrating operation. Variations in the manufacturing process and environmental conditions (such as the total conductivity of the sample solution) can cause changes in the absolute conductance between the electrodes. However, such changes do not interfere with the derivation of the pH of the sample solution. This is because the pH is determined by the rate of change of conductance rather than by the absolute value of the conductance. Of course, such systems can be used in conjunction with a reference electrode to account for environmental changes in conductivity. An exemplary pH sensor package 130412.doc 200914822 in accordance with the present disclosure includes a pair of electrodes 12 and 12 covered with a sigma/polymer 14,; a certain time == 16; - an alternating frequency between 1 〇交流 along with the Mhz AC power supply 18; in the material field "22, a s memory 24, which stores the measured conductance value between the electrodes and a look-up table for the conductivity change gradient and its corresponding value; Message or display port - the pH of the assembly 26. The switch i 6 turns the connection between the AC power source and the electrode on and off at a given time interval. The current through the electrodes is measured and converted by the data processor into corresponding electrical conductance in the memory. The data processor calculates the conductance change gradient and compares 纟 to the value for the compound/polymer in the lookup table and reports the current pH of sample solution 10. The electrodes can be of any suitable configuration, without the need for a flat plate as shown, in any convenient shape and arrangement. In addition, a system clock can be used to synchronize the data stream with the processing. In a specific embodiment, the pH sensing device includes a pair of electrodes 12, 12', a connection 15 to the pair of electrodes 12, 12, and a compound/polymer coating 14 on at least one of the electrodes. The polymer is soluble in a solution, and the rate of resolution may depend on the pH of the solution. In other embodiments, the pH sensing device may further include a pair of power source electrodes 12, 12' The electrical switch 16 between the connections. In addition, the PH sensing device can include a data processing (4) for connecting 20 to the power source 18, and a data memory component 24 connected to the data processor. - Exemplary implementation In one embodiment, the pH sensor comprises a pair of compound/polymer coated electrodes dissolved in a solution having a pH between about 2 and about 6.5. The presence of H+ ions can affect the dissolution of a particular compound/polymer. 130412.doc -11 - 200914822 degrees, for example, a polymer commonly used as a casing for pharmaceuticals. Examples of the above polymers are synthetic acrylic polymers for coating pharmaceutical dosage forms under the trade name EUDRAGIT (Rohm GmbH, Germany). EUDRAGIT polymer solubility The quality depends on the solution conditions, in particular the pH of the solution. The enteric coating is specially designed to have solubility properties compatible with the desired stage of the digestive tract. For example, EUDRAGIT L100 is before pH above 6.0 (dissolved pH threshold) It is insoluble in water and has a 10-fold increase in dissolution rate from pH 6.1 to pH 7.1. In addition, the properties of the above polymers are highly stable to the environment during storage and are not harmful to the skin, ie no to body tissues and body fluids. Role (see "Ultra DRAGIT film coating practical course for pharmaceutical dosage forms π, Rohm GmbH, Germany, 2001). These polymers are poor electrical conductors when they are in solid state. EUDRAGIT polymerization for pH sensing devices The composition includes a mercaptoacrylic acid polymer, a mercaptoacrylate polymer, an aminoalkyl methacrylate polymer, and an ammonium alkyl methacrylate polymer. In addition to the EUDRAGIT polymer, it is used in the pH correlation of the present disclosure. The implementation of suitable polymers includes any polymer having a pH-related solubility. Suitable polymers include poly(vinyl acetate) polymerization of vinyl phthalate. , hydroxypropyl methyl cellulose phthalate polymer, cellulose acetate phthalate polymer and cellulose acetate polymer. Also suitable for the pH disclosed in the present disclosure The sensing device is a compound/polymer having a threshold pH of between about 5 and about 7, which means that the compound/polymer dissolves in a solution having a pH between about 5 and about 7. In addition, having a ratio of about 4 to A compound/polymer of a threshold pH of about 6 is also suitable, and the above compound/poly 130412.doc •12·200914822 is/combined in a solution having a pH between about 4 and about 6. In addition, the compound/polymer used is soluble in a solution having a pH between about 2 and about 65. The compound/polymer may have a solubility rate suitable for the application, so the rate is not so fast that it is difficult to measure the rate and/or a particularly thick compound/polymer coating is required, nor is it too slow to dissolve so that it is difficult in a short time The change in conductance is measured internally. Preferably, the compounds/polymers have a maximum solubility rate of greater than about i mm / ι 〇〇. Similarly, the compounds/polymers preferably have a range of solubility rates that are 10 times greater, and therefore at this threshold? The 11' compound/polymer dissolves at a rate of 1 micron per minute and the rate is increased to a maximum of about 20 microns per minute. In order to encompass a wider pH range than can be achieved with a single compound/polymer, multiple pairs of electrodes can advantageously be used in a single pH sensor system in accordance with the present disclosure, each having a dissolution threshold Compound/polymer coating. In another embodiment in accordance with the present disclosure, a pH sensor is provided that includes a pair of electrodes and that coats each pair of electrodes with a compound/polymer having a different solubility pH threshold. Disclosed herein is a pH sensor in which two or more pairs of electrodes are coated with a compound/polymer having a pH threshold different from another pair of electrodes. Using a pair of electrodes coated with a compound/polymer having different pH thresholds, the disclosed pH sensor can sense a wider range of pH and achieve better accuracy. For example, electrodes can be designated for detecting the pH of different regions of the digestive tract, including the stomach and intestine, which have different pH ranges. In an application such as an ingestible pill, the pH sensor may have an electrode dedicated to detecting 130412.doc -13· 200914822 present in the low pH of the stomach t, but having an insoluble at the low pH described above. The compound/polymer electrode has just remained intact as the sensor reaches the higher positive region of the intestine. As shown in Figure 2, an exemplary pH sensor having a first pair of electrodes 25, 25 coated with a first compound/polymer 28. The apparatus further includes a second pair of electrodes 29, Μ coated with a second compound/polymer 30. The second compound: the polymer is soluble in a solution, and the rate of solubility may depend on the pH of the solution. I’m on the same sound.

C Ό * $ body example, the first compound / polymer in

Not soluble below a measured value, and the second compound is insoluble below the second pH threshold. In another embodiment, the first compound/polymer is insoluble above the -PH threshold and the second compound/polymer is insoluble below the second pH threshold. In yet another embodiment, the first compound/polymer is insoluble at less than a positive inter-value and the second compound/polymer is insoluble below a second P-off value. The electrodes are exposed to a sample solution 27 as shown in Figure 2, and each pair is monitored by applying an -AC voltage 18 to the electrodes at constant time intervals; the impedance or conductance between the electrodes. The impedance value of at least two consecutive measured values is used to calculate the conductance variable speed 1. The calculated rate of change of conductance is the limit of the pH before storage === or the actual positive value of the sample solution. According to the present disclosure, the pH sensor can have the same electrode pH as above for any other electrode pair coated with a compound/polymer coated with a polymer having a value between 2 and 6.5. Please pay attention to the electrode shown in Figure 2. According to f, you can use two plates, such as *, ,.. 'All electrodes need not be made on the separate carrier shown in Figure 2, 130412.doc -14- 200914822 can be made on the same physical carrier. A system clock (not shown here) can be used to synchronize the data stream with the processing. Referring to Figure 3, the pH sensing device includes a second compound/polymer 38 that coats the first compound/polymer 36 of the electrode pair 39, 39. The second s/1 sputum can be used to protect the first compound/polymer from being dissolved prior to dissolution of the second compound polymer. This combination can be designed to allow detection of the PH in the digestive tract that needs to pass through an area of an earlier region having a similar pH. In a specific embodiment, the first compound/polymer is insoluble at a pH below -PH, and the second compound/polymer is "not soluble at a lower than the second pH threshold. In another implementation In one example, the first compound/polymer 36 is insoluble above a pH threshold and the second compound/polymer 38 is insoluble below a second value. In yet another embodiment, the - compound/polymer 36 is insoluble at temperatures above -ρ, and second compound/polymer 38 is not resolved above the second pH. In yet another embodiment, the A compound, polymer 36 is insoluble at less than a dose of the agent, and the second compound/polymer 38 is insoluble at a temperature above the second pH threshold. The germanium sensor can include at least one pair of electrodes, A thicker first compound/polymer having a defined pH threshold is initially coated with a thinner first compound/polymer that is different from the pH threshold of the first compound/polymer. In this configuration, Protecting the human-M ^ 〇 / / 1 compound from unexpected The violent path. For example, 'manufacturing a compound/polymer system when the enthalpy is higher than j: ΡΗ in the intestine, a suitable polymer. However, ingestible pills 4 " insoluble compounds / v The sensor is swallowed by the patient 130412.doc -15 - 200914822 and shortly thereafter, the sensor may have exposure to a liquid with a pH above 6. In order to protect the sensor from unintended Or premature exposure, a compound/polymer that does not dissolve before pH below 5 can be used as a thin coating on the compound/polymer with a pH threshold of 6. The thin topcoat is in the low pH environment of the stomach. Quickly dissolves, and the colon pH sensor will be ready for deployment. The sensed dissolution of the thin coating may be too fast to provide an accurate pH value, but can be used as a PH sensor to pass the pill Landmark.

Referring now to Figure 4, the disclosed pH sensing device can include a protective layer 46 interposed between electrode 42 and compound/polymer coating 48. As shown in Figure 4, an exemplary electrode 42 is mounted on a substrate 44 and primed with a protective layer 46 before it is covered by the compound/polymer 48. The protective layer may be formed of a suitable material such as chromium, gold, platinum, metal oxide or polyurethane. The protective layer is used to protect the electrode from corrosion in a sample solution such as a gastrointestinal fluid. Referring to Figure 5', a cross section of the electrode array 5A is shown. The array of electrode pairs is part of a single-PH sensing device. As shown, the array % comprises six pairs of electrodes' each pair having an electrode coated with a compound/polymer different from the other coated electrode. Although only the __to-electrode 52 is coupled to the circuit 54, the electrodes are connected to the circuit, the circuit includes a power source, a switching mechanism, and an associated component for determining the rate of change of impedance. The sensor array 50 can include a number of pairs of electrodes. Each electrode pair can be decomposed in a -fluid (such as H+, Na+, enzyme, glucose, protein/, virus, bacteria, amine based, + # or /, his factors) with substance concentration as a change compound / polymerization The material is coated. Therefore, it can be used to detect the presence and concentration of PH and other components in the sample solution. In a specific embodiment, at least two pairs of electrodes are coated with different compounds/polymers that react to different materials and/or different concentration ranges. The grid structure facilitates filling of the polymer and the depth of each well can be adjusted based on the desired operating time of the sensor. Ο The pH can be determined by knowing the probability of known solubility in a given solution. The pH sensing device allows the rate of solubility to be taken as the time derivative of the fluid conductivity. Since this coating compound/polymer has a different conductivity than the solution, as the compound/polymer dissolves, the liquid fills the gap between the electrodes and causes an increase in electrical conductivity. The conductivity change can be similarly applied to the following analyte concentrations? The equation for the 11 threshold is associated with the solubility rate of the polymer. Equation 1

% in ^electrodesPfluid (^*>Q dYp{r,t^

Z dt

+ Q 'hreshold

In Equation 1, c is the measured solubility rate, where % is the proportional coefficient, such as the distance between the electrodes, the resistivity of the P//- solution, the solubility rate at the pH threshold, and the γ system. Conductivity between the electrodes. A system for detecting the pH in a solution is also provided. The system includes a compound/polymer coated electrode and means for determining the conductance of a solution at the electrode. The means for determining includes any suitable electronic system, including circuitry for determining the rate of change of conductance, as is known in the art. In the disclosed system, the compound/polymer is soluble in solution 130412.doc -17- 200914822 and the rate of solubility may depend on the pH of the solution. = Method of providing the pH of the seedlings - (iv). The method comprises providing one: an electrode in a compound/polymer or coated with a compound/polymer. The material/polymer has a pH dependent solubility profile. This handsome ☆ solution can be known in the art or it can be determined empirically. The I step involves exposing the compound/polymer coated electrode to a solution - and determining the conductance at the electrode as a function of time. The conductivity '1' was determined by determining the pH of the solution by correlating the conductivity with the compound/polymer solubility. The present disclosure provides a manufacturing method and/or technique for pH sensors that are small, low-definition, non-calibrated, and sufficiently reliable to monitor pH as they pass through the gastrointestinal tract. In addition, the disclosed pH sensor can be used as a disposable sensor to monitor continuous pH changes in other environments, such as within hours. Based on the same theory, a sensor array that senses multiple substances and/or properties can be fabricated and implemented in a variety of environments. An example of a device comprising a plurality of electrodes is shown in Figures 6 and 6B. The G pH sensing device contains a plurality of electrode arrays dispersed between three stacked layers. A device configured in this manner is sized to allow the device to be ingested and available for other ionic and biological factors? 11 information and concentration information. EXAMPLES Example 1: Determination of the impedance of an electrode immersed in a sample of liquid using a polymer coated electrode. Use—An array of interdigitated electrodes coated with EUDRAGIT polymer L30-D55 or E100. Three sample solutions were used. The two solutions are brines having a salt content of 〇·2% to 0·6 /〇 w/v and a pH of 5.7. Adjust the pH with hydrochloric acid and use a 130412.doc 200914822

Corning (glass electrode) pH meter CHEKMITE PH-15 calibrates the pH of the sample. A simulated gastric juice (SGF) of not 3 protein shells (Ricca Chemical Part # 7108-32) was used, which was 〇.7〇/ at a pH of l.i. 0.2% w/v in v/v HC1

NaCl. Simulated intestinal fluid (SIF) uspxxn (Ricca chemical)

Part# 7109.75-16), which is 〇68% scalar monopotassium and sodium hydroxide. The final solution was pH 7.4. Two electrodes coated with the same polymer L3〇_D55 which were insoluble before pH 5 5 were respectively immersed in three sample solutions. Due to the dissolution of the polymer (the conductivity between the electrodes changes with time. The conductivity change rate is well differentiated in fluids with different pH values. For a solution with a capacitance of _3 3 nanofarads (nf), pH 7.4, as a resistor The reciprocal of the impedance reported by MicroSiemens (ms) rises rapidly to 63 ms. The impedance change of the pH 5.7 solution is not so large, only 36 ms and the capacitance is -0.6 nf, and the impedance of the solution of pH K1 does not change much to 48 ms. - 9.1 Capacitance The same electrode coated with the same polymer L30-D55 was continuously immersed in a fluid having a pH value of I. T. Although the solution was contacted with a solution of different pH values, the rate of conductance change depending on the pH remained the same. Additional experiments were conducted to confirm that the salt content of 〇2% to 1% did not affect the reaction of the polymer. Similar reproducibility of other polymers has been demonstrated, including polymers that are insoluble before the pH is below 5. In the present disclosure, additional compounds and/or polymers having other pH thresholds can be used. Therefore, by using a plurality of pairs of electrodes coated with different values of the compound/polymer, it can be smothered. pH sensor monitoring is large The pH of the range. Similarly, the polyp analyte content of the octave p 1 θ 疋 可 can be determined as described herein. 130412.doc -19- 200914822 Although the present invention has been carried out (iv) and described, The present invention is not limited to the details shown in the drawings. The various details can be applied to the details within the scope of the patent application and without departing from the present invention. Figure 1 is a schematic illustration of a specific embodiment of a pH sensor in accordance with the present disclosure

2 is a schematic illustration of another embodiment of a pH sensor in accordance with the present disclosure. DETAILED DESCRIPTION OF THE INVENTION Figure 3 is another schematic illustration of a pH sensor in accordance with the present disclosure. 4 is a schematic illustration of an embodiment of a coated electrode in accordance with the present disclosure. Figure 5 is a schematic illustration of a pH sensor containing an electrode array in accordance with a particular embodiment of the present disclosure. Figure 6A is a schematic illustration of a pH sensor containing an electrode array in accordance with an embodiment of the present disclosure. Figure 6B is a side view of the pH sensor shown in Figure 6A. [Main component symbol description] 10 Sample solution 12 Electrode 12, Electrode 14 Compound/polymer coating 15 Connection 16 Electrical switch 130412.doc -20- 200914822 18 Power supply 20 Connection 22 Data processor 24 Data memory component 25 Electrode 25 'Electrode 26 Reports or displays a pH component 28 First Compound / Polymer 29 Electrode 29' Electrode 30 Second Compound / Polymer 36 First Compound / Polymer 38 Second Compound / Polymer 39 Electrode 39 ' Electrode 42 Electrode 44 Substrate 46 Protective layer 48 Compound/Polymer Coating 130412.doc -21 -

Claims (1)

200914822 X. Patent application scope: 1. A biochemical sensing device comprising: a. at least one electrode (12); b. - a power source (18) connected to the electrode; and c. a compound on the electrode Coating (14) wherein the compound is soluble in one of the analyte solutions and the rate of solubility is dependent on the analyte concentration of the solution. 2. A pH sensing device comprising: a. — an electrode (12); b. — a power source (18) connected to the electrode; and c. a polymer coating on the electrode (丨4) Wherein the polymer T is soluble in / trough and its rate of solubility is dependent on the pH of the solution. 3. A biochemical/pH sensing device as claimed in claim 1 or 2, further comprising an electrical switch (16) at the junction between the power source and the electrode. 4. A biochemical/pH sensing device as claimed in claim 1 or 2, further comprising a data processor (22) coupled to the power source (18). 5. The biochemical/pH sensing device of claim 4, further comprising a data memory component (24) coupled to the data processor. 6. The pH sensing device of claim 2, wherein the polymer (28) is insoluble at a pH below a pH, and the device further comprises - coated by the second layer (30) a second electrode (29) 'where the second polymer is chillable in/in solution' and its rate of solubility is dependent on the pH of the solution and progresses when the second polymer is below a second pH threshold Not soluble. The method of claim 2, wherein the polymer is insoluble at a pH above a pH threshold, and the device further comprises a second electrode coated by a second polymer, wherein the The second polymer is soluble in a solution and its rate of solubility is dependent on the pH of the solution, and further wherein the second polymer is insoluble below a second pH threshold. 8. The pH sensing device of claim 2, wherein the polymer is insoluble below a pH threshold, and the device further comprises a second electrode coated by a second polymer, wherein the second polymer Is soluble in a solution, and its rate of solubility is dependent on the pH of the solution, and further wherein the second polymer is insoluble below a second pH threshold. 9. The pH sensing device of claim 2, wherein the device further comprises a second polymer (38) overlying the polymer (36) coating the electrode (39). 10. The pH sensing device of claim 9, wherein the polymer (36) is insoluble below a pH threshold and the second polymer (38) is soluble in a solution and The rate of solubility is dependent on the pH of the solution, and further wherein the second polymer is insoluble below a second pH threshold. 11. The pH sensing device of claim 9, wherein the polymer (36) is insoluble above a pH threshold and the second polymer (38) is soluble in a solution and the solubility rate thereof Depending on the pH of the solution, and further wherein the second polymer is insoluble below a second pH threshold. 12. The pH sensing device of claim 9, wherein the polymer (36) is insoluble above a pH threshold and the second polymer (38) is soluble in a solution and the solubility rate thereof Depending on the pH of the solution, and further wherein the second polymer is insoluble above a second pH threshold. 130412.doc 200914822 The PH sensing device of long term 9, wherein the polymer (36) is insoluble at a threshold below a P, and the second polymer (38) is soluble in a solution A, and the solubility thereof The rate is dependent on the pH of the solution, and further the ruthenium (tetra) dipolymer is insoluble at above the -first:pH threshold. The biochemical sensing skirt of claim 1 further includes a reference electrode coupled to the power source, wherein the reference electrode is not coated with a solubilized person. The biochemical sensing device of claim 1 further comprising a protective layer (46) between the electrode (42) and the polymer coating (48). 16. The PH sensing device of claim 2, wherein the polymer is selected from the group consisting of a methyl methacrylate polymer, a methacrylate polymer, an amine methacrylate polymer, and a methacrylic acid (tetra) methacrylate. The purpose is to group the polymer. 17. The pH sensing device of claim 2, wherein the polymer is selected from the group consisting of polyvinyl phthalate polymer, hydroxypropyl decyl cellulose ester phthalate, and trimellitic acid acetate. A group consisting of a cellulose ester polymer and a cellulose acetate phthalate polymer. 18. The pH sensing device of claim 2, wherein the polymer is soluble in a solution having a pH between about 5 and about 7. 19. The pH sensing device of claim 2, wherein the polymer is soluble in a solution having a pH between about 4 and about 6. 20. The pH sensing device of claim 2, wherein the polymer is soluble in a solution having a pH between about 2 and about 6.5. A system for detecting the pH in a solution comprising a polymer coated electrode and a device for determining the rate of change of conductance at the electrode 130412.doc 200914822, wherein the polymer is soluble In the solution 'and its rate of solubility depends on the pH of the solution. 22. A method for determining a solution, the method comprising: a. providing an electrode coated in a polymer having a pH-dependent solubility profile in the crucible; b. The coated electrode is exposed to the solution; c. determining the conductivity at the electrode, expressed as a function of time; d. correlating the conductivity with the solubility of the polymer to determine the pH of the solution. 23. A method for determining - solution-analyte concentration, the method comprising: a. providing an electrode coated in a compound, wherein the compound has a solubility profile depending on the concentration of the analyte of the solution b. exposing the electrode coated with the compound to the solution; c. determining the conductivity at the electrode, expressed as a function of time; and d. correlating the conductivity with the solubility of the compound to determine the solution The analyte concentration. 130412.doc