TW201421023A - Chlorine ion measurement system - Google Patents

Abstract

The invention relates to a chlorine ion measurement system, including: a container used for containing a measurand solution; a reference electrode disposed in the container for contacting the measurand solution; a chlorine ion sensing element disposed in the container for contacting the measurand solution, wherein the chlorine ion sensing element includes: a substrate; an oxide film formed on the substrate; and a chlorine ion sensing film formed on the oxide film; and an instrumentation amplifier coupling to the chlorine ion sensing film and the reference electrode by a first wire and a second wire respectively, wherein the chlorine ion sensing film couples to a negative input terminal of the instrumentation amplifier and the reference electrode couples to a positive input terminal of the instrumentation amplifier.

Description

Chloride sensing system

The present invention relates to a chloride ion sensing system, and more particularly to a chloride ion sensor for detecting a low concentration chloride ion solution.

Conventionally, when a glass electrode is used as a measuring electrode for ion sensing, its application range is considerably limited due to the inability to quantify the measurement, the damage, and the inconvenience of carrying it. Piet Bergveld proposed the Ion Sensitive Field Effect Transistor (ISFET) in 1970. Its structure is similar to that of Metal Oxide Semiconductor Field Effect Transistor (MOSFET). The main difference is ion sensing. The field effect transistor replaces the metal gate of the gold oxide half field effect transistor with the sensing film and the electrolyte. Although the ion-sensing field-effect transistor itself is combined with CMOS process technology, its sensing film preparation is not suitable for standard process technology. It requires an additional mask to make the upper area of the gate, which is costly and reduces productivity.

In 1983, J. Van Der Spiegel et al. proposed an Extended Gate Field Effect Transistor (EGFET) structure to improve the shortcomings of ion sensing field effect transistors. The extended gate sensing field effect crystal system retains the metal gate of the gold oxide half field effect transistor, and separates the sensing region from the gate of the gold oxide half field effect transistor, and the two are electrically connected to each other by a conductive material. connection. The extended gate sensing field effect transistor has the following advantages over the ion sensing field effect transistor: (1) the wire can provide electrostatic protection to the component, and (2) the component electrical region can be avoided directly with the aqueous solution. The contact, and (3) process is fully compatible with the MOS half-field transistor technology and the cost is reduced.

Patent No. 564476 of the Republic of China is a patent related to extended gate sensing field effect transistors. This patent discloses a single wafer that simultaneously detects pH, temperature and light intensity. Its circuit output signal has a high degree of linearity. The wafer can be used as an instant monitoring and back-end compensation for the effects of temperature and light on the extended gate ion sensor.

U.S. Patent No. 6015480 is also a related patent for extended gate sensing field effect transistors. This patent discloses a method for measuring the lifetime of an extended chloride ion sensing membrane. The ISE sensor provides a dual layer sensor structure for the fourth level ion-selective polymerization layer, which is located in a sample to be analyzed and a Ion exchangers are used between commercial polymeric ISE films. The polymeric structure includes a methyl methacrylate/chloromethyl styrene copolymer and a third-generation amine mixture associated with the reaction.

U.S. Patent No. 6,350,524 discloses a chloride ion selective electrode comprising a layer of a metal salt which is insoluble and a hydrophilic polyurethane protective film disposed thereon. The hydrophilic polyurethane is coated on a chloride ion selective electrode to have a fast response time response and to accurately measure chloride. The use of bromide or iodide can also reduce interference or prevent protein adsorption to the electrode surface.

However, none of the above chloride ion sensors can be used to sense a low concentration of chloride ion solution. Therefore, there is still a need for a chloride ion sensor that can be used for a low concentration chloride ion solution.

The invention provides a chloride ion sensor for detecting a low concentration chloride ion solution, comprising a container for accommodating a solution to be tested; a reference electrode disposed in the container for contacting the solution to be tested; An ion sensing element disposed in the container to be in contact with the solution to be tested, wherein the chloride ion sensing element comprises: a substrate; an oxide film formed on the substrate; and a chloride ion sensing film formed on the oxide film And an instrumentation amplifier coupled to the chloride ion sensing component and the reference electrode through a first wire and a second wire, wherein the chloride ion sensing component is coupled to one of the negative input terminals of the instrumentation amplifier and the reference electrode is coupled One of the instrumentation amplifiers has a positive input.

The above and other objects, features and advantages of the present invention will become more <RTIgt;

The making and using of the embodiments of the present invention are described below. The embodiments of the present invention provide many suitable inventive concepts and can be widely implemented in various specific contexts. The specific embodiments disclosed are merely illustrative of the invention, and are not intended to limit the scope of the invention.

Please refer to FIG. 1. FIG. 1 is a configuration diagram showing a chloride ion sensing system according to an embodiment of the present invention. The chloride ion sensing system 100 includes a chloride ion sensing element 102, a reference electrode 104, and an instrumentation amplifier 106, wherein the chloride ion sensing element 102 and the reference electrode 104 are respectively a first wire 102a The second wire 104a is coupled to the instrumentation amplifier 106. The first wire 102a and the chloride ion sensing element 102 may be coupled by a conductive paste (eg, silver paste). In the embodiment of the present invention, the chloride ion sensing component 102 is coupled to the negative input terminal 106a of the instrumentation amplifier 106 through the first wire 102a, and the reference electrode 104 is coupled to the positive input terminal 106b of the instrumentation amplifier 106 through the second wire 104a. The reference electrode 104 can be a silver/silver chloride (Ag/AgCl) reference electrode, or other suitable reference electrode. The first wire 102a and the second wire 104a may each be an aluminum wire, a copper wire, a metal wire, or a combination thereof. In an embodiment of the invention, instrumentation amplifier 106 may be a circuit or wafer having a function of amplifying differential voltage, such as LT1167, AD620, or other suitable wafer and circuit. The reference electrode 104 of the chloride ion sensing system 100 and the chloride ion sensing element 102 are placed in the solution 110 to be tested in the container 108 to be in contact therewith. According to an embodiment of the invention, the solution to be tested 110 may be a solution having a low chloride ion concentration, for example, a bleaching aqueous solution, or other commercially available chloride ion solution. In some embodiments of the invention, the chloride concentration of the solution to be tested 110 is about 0.1 to 10 ppm. The container 108 is a container that can block light.

Still referring to FIG. 1, the voltage signal output by the instrumentation amplifier 106 can be received through the electric meter 120, and the signal output by the electric meter 120 can be displayed by the display device 122.

2 is a cross-sectional view showing the chloride ion sensing element 102 in accordance with an embodiment of the present invention. Referring to FIG. 2, the chloride ion sensing element 102 is composed of a substrate 202, an oxide film 204, and a chloride ion sensing film 206. Substrate 202 can include a semiconductor substrate (eg, a germanium substrate), a glass substrate, or a combination of the foregoing. The oxide film 204 may include indium tin oxide, antimony oxide, or a combination of the foregoing. In one embodiment, substrate 202 is a germanium substrate and oxide film 204 is germanium oxide. In another embodiment, substrate 202 is a glass substrate and oxide film 204 is indium tin oxide. The chloride ion sensing film 206 may be composed of a polymer material, a plasticizer, and a chloride having a weight ratio of about 5 to 15:15 to 30:1 to 5. For example, the polymer material may include a high molecular polymer such as polyvinyl chloride (PVC), and the plasticizer may include plasticization such as bis(2-ethylhexyl)sebacate (DOS). And the chloride may include a chloride ion carrier ({u-[4,5-Dimethyl-3,6-bis(dodecyloxy)-1,2-phenylene]}bis (mercury chloride), ETH 9033) and the like. In one embodiment, the weight ratio of the polymer material, the plasticizer, and the chloride constituting the chloride ion sensing film 206 is about 15:30:1. The chloride ion sensing film 206 is formed by dissolving a polymer material and a plasticizer in a solvent of tetrahydrofuran (THF) to form a polymer solution, and further dissolving the chloride in a ratio of chloride to tetrahydrofuran. A chloride solution is formed. Next, the polymer solution and the chloride solution are uniformly mixed and then applied onto the oxide film 204 by a coating process. For example, by applying a spin coating process to the oxide film 204, the rotational speed of the spin coating process can be about 1000 to 5000 rpm, and the preferred rotation speed is 4000 rpm. Finally, the wet film coated on the oxide film 204 is dried at room temperature to complete the preparation of the chloride ion sensing film 206. The chloride ion sensing element 102 can further include an insulating layer 208. As shown in FIG. 2, the insulating layer 208 covers the surface of the substrate 202 and the oxide film 204 and the insulating layer 208 has a window 208a. The window 208a exposes chloride ions. The film 206 is sensed. The material of the insulating layer 208 may include epoxy, SiO ₂ , or a combination thereof.

The chloride ion sensing system provided by the present invention can be applied to a solution for measuring a low chloride ion concentration, for example, a solution having a chloride ion concentration of 0.1 to 10 ppm.

The following is a preferred embodiment of the present invention. It is noted that although the preferred embodiment of the present invention constitutes a chloride ion sensing film in a specific ratio and material, the chloride ion sensing film of the present invention is not limited to these. The ratio and material are as long as the prepared chloride ion sensing membrane can be combined with the chloride ion sensing system of the present invention and produces an effect that can be applied to the measurement of a low chloride ion concentration solution.

[Example 1] Preparation of chloride ion sensing element Preparation of oxide film

A p-type semiconductor germanium substrate was used as a substrate, and a base metal having a diameter of 2 inches, a thickness of 3 cm, and a purity of 99.99% was used as a target. The pressure of the reaction chamber of the vacuum sputtering machine is pumped to below 5×10 ^-6 Torr, and a mixed gas of argon/oxygen (40 sccm/20 sccm) is introduced, and the pressure is controlled to 10×10 ^{− 3} Torr, the RF power was adjusted to 100 watts (W), and sputtering was performed for 15 minutes to prepare a yttrium oxide film on the p-type semiconductor ruthenium substrate. Thereafter, the p-type semiconductor substrate having the ruthenium oxide film is further sliced to a size of about 0.5 square centimeter (cm ² ), and a metal wire is bonded to the surface of the ruthenium oxide film with silver paste. Thereafter, the above-described p-type semiconductor substrate having a hafnium oxide film was coated with an epoxy resin (Epoxy), leaving only a sensing window of about 0.2 square centimeters (cm ² ) and exposing the hafnium oxide film in the sensing window.

Preparation of chloride ion sensing membrane

First, 0.33 g of a polyvinyl chloride polymer material and 0.66 g of a dioctyl sebacate plasticizer were mixed to form a polymer mixture. After that, the polymer mixture was added to 5 mL of tetrahydrofuran (tetrahydrofuran, In a solvent of THF), polyvinyl chloride was completely dissolved in a tetrahydrofuran solvent by an ultrasonic oscillator to form a polymer solution.

Next, 0.022 g of {u-[4,5-Dimethyl-3,6-bis(dodecyloxy)-1,2-phenylene]}bis(mercury chloride) chloride (ETH9033) was added to 1 mL of tetrahydrofuran solvent. The ETH9033 chloride was completely dissolved in tetrahydrofuran solvent with an ultrasonic oscillator to form an ETH9033 solution. Add 20 μL of the polymer solution to an appropriate amount of ETH9033 solution, and mix it thoroughly with an ultrasonic oscillator to form a chloride ion solution. Finally, 2 μL of the chloride ion solution is applied to the surface of the cerium oxide film in the sensing window by using a spin coating process, and is naturally dried at room temperature for 8 hours to form a chloride ion sensing film, and further The preparation of the chloride ion sensing element is completed.

Chloride sensing system configuration

The prepared chloride ion sensing element and the silver/silver chloride (Ag/AgCl) reference electrode are respectively connected to the negative input terminal and the positive input terminal of the LT1167 instrumentation amplifier by an aluminum wire, and the chloride ion sensing element and the silver ion sensor are respectively connected. The /silver chloride reference electrode is fixed in a container containing the solution to be tested. Finally, the output of the LT1167 instrumentation amplifier is connected to an NI-DAQCard meter.

Measurement test of solution solution to be tested

The liquid to be tested is selected from the commercial standard chloride ion solution (represented by Yuanhong Co., Ltd.) and bleach (produced by Kao Co., Ltd.), and the standard chloride ion solution and the chloride ion concentration in the bleaching water are measured. Electricity The results of the polar surface potential are shown in Figures 3 and 4, and Figure 3 is the result of the response voltage measured by the chloride ion sensing element from 0 ppm to 10 ppm of the commercial standard chloride solution. The sensitivity and linear regression were 10.04 mV/ppm and 0.996, respectively. Figure 4 shows the response voltage of the chloride ion sensing element measured at 0 ppm to 10 ppm of bleach. The sensitivity and linear regression were 15.33 mV/ppm and 0.990, respectively.

Figure 5 is an equivalent circuit diagram of the chloride ion sensing element, R _s 301 is the equivalent resistance of the solution to be tested, R _ct 302 is the charge transfer resistance of the chloride ion sensing film, and C _dl 303 is the chloride ion sensing film. Double layer capacitor.

Figure 6 is a measurement of the electrochemical impedance analyzer of a commercialized standard chloride ion solution concentration. Referring to FIG. 6, when the concentration of the commercial standard chloride ion solution is lower, the less the transmission between the chloride ion and the chloride ion sensing film leads to an increase in impedance, so it can be confirmed that the chloride ion sensing system of the present invention can be applied to low. The concentration of the chloride ion solution is measured.

While the invention has been described above in terms of several preferred embodiments, it is not intended to limit the scope of the present invention, and any one of ordinary skill in the art can make any changes without departing from the spirit and scope of the invention. And the scope of the present invention is defined by the scope of the appended claims.

100‧‧‧ chloride ion sensing system

102‧‧‧ chloride ion sensing element

104‧‧‧ reference electrode

102a, 104a‧‧‧ wire

106‧‧‧Instrument Amplifier

106a‧‧‧negative input

106b‧‧‧ positive input

108‧‧‧ Container

110‧‧‧Test solution

120‧‧‧Electric meter

122‧‧‧ display device

202‧‧‧Base

204‧‧‧Oxide film

206‧‧‧ chloride ion sensing membrane

208‧‧‧Insulation

208a‧‧‧ window

1 is a configuration diagram showing a chloride ion sensing system according to an embodiment of the present invention; FIG. 2 is a schematic cross-sectional view showing a chloride ion sensing element 102 according to an embodiment of the present invention; and FIG. 3 is a diagram according to the present invention. The figure shows the relationship between the chloride ion concentration of the commercial standard chloride ion solution and the measured reaction voltage; and FIG. 4 shows the chloride ion concentration of the bleach water and the measured reaction according to an embodiment of the present invention. FIG. 5 is an equivalent circuit diagram of a chloride ion sensing element according to an embodiment of the invention; FIG. 6 is a diagram showing a chloride ion of a commercial standard chloride ion solution according to an embodiment of the invention. Data chart of the measurement results of the electrochemical impedance analyzer of the concentration.

100‧‧‧ chloride ion sensing system

102‧‧‧ chloride ion sensing element

104‧‧‧ reference electrode

102a, 104a‧‧‧ wire

106‧‧‧Instrument Amplifier

106a‧‧‧negative input

106b‧‧‧ positive input

108‧‧‧ Container

110‧‧‧Test solution

120‧‧‧Electric meter

122‧‧‧ display device

Claims (15)

A chloride ion sensing system includes: a container for accommodating a solution to be tested; a reference electrode disposed in the container to be in contact with the solution to be tested; and a chloride ion sensing element disposed in the container In contact with the solution to be tested, wherein the chloride ion sensing element comprises: a substrate; an oxide film formed on the substrate; and a chloride ion sensing film formed on the oxide film; and a The instrumentation amplifier is coupled to the reference electrode by a first wire and a second wire respectively, wherein the chloride sensing element is coupled to one of the negative input terminals of the instrumentation amplifier and the reference electrode is coupled Connect to one of the positive inputs of the instrumentation amplifier. The chloride ion sensing system of claim 1, wherein the substrate comprises a semiconductor substrate, a glass substrate, or a combination of the foregoing. The chloride ion sensing system of claim 1, wherein the oxide film comprises indium tin oxide, antimony oxide, or a combination thereof. The chloride ion sensing system of claim 1, wherein the substrate is a germanium substrate and the oxide film is a hafnium oxide film. The chloride ion sensing system of claim 1, wherein the substrate is a glass substrate and the oxide film is an indium tin oxide film. The chloride ion sensing system according to claim 1, wherein the chloride ion sensing film is a polymer material and a plasticizer in a weight ratio of about 5 to 15:15 to 30:1 to 5 And a composition of monochloride. The chloride ion sensing system of claim 6, wherein the weight ratio of the polymer material, the plasticizer, and the chloride is about 15:30:1. The chloride ion sensing system of claim 6, wherein the polymer comprises poly vinyl chloride (PVC). As for the chloride ion sensing system described in claim 6, the chloride includes a chloride ion carrier ({u-[4,5-Dimethyl-3,6-bis(dodecyloxy)-1,2-phenylene]}bis) (mercury chloride), ETH 9033). The chloride ion sensing system of claim 1, wherein the chloride ion sensing element further comprises: an insulating layer covering the oxide film and the surface of the substrate and having a window, wherein the window The chloride ion sensing membrane is exposed. The chloride ion sensing system of claim 10, wherein the insulating layer comprises epoxy, SiO ₂ , or a combination thereof. The chloride ion sensing system of claim 1, wherein the reference electrode is a silver/silver chloride (Ag/AgCl) reference electrode. The chloride ion sensing system of claim 1, wherein the instrumentation amplifier is an LT1167 instrumentation amplifier. The chloride ion sensing system of claim 1, wherein the solution to be tested is a chloride ion solution or a bleaching aqueous solution, wherein the solution to be tested has a chloride ion concentration of about 0.1-10 ppm. The chloride ion sensing system of claim 1, wherein the first and second wires each comprise an aluminum wire, a copper wire, a metal wire, or a combination thereof.