TWI589868B - Method for making test strip and method for detecting phosphoric acid concentration - Google Patents

Description

Method for preparing test piece and method for detecting phosphoric acid concentration

The invention relates to a detection method, in particular to a method for preparing a test piece and a method for detecting the concentration of phosphoric acid.

In order to produce a uniform and uniform nanopore, anodizing is a common method of using aluminum metal as an anode and etching the nanostructure on the surface of the aluminum metal through an electrochemical etching mode. The uniformity and quality of the nanostructure are highly dependent on the concentration of the acid used in the reaction. Therefore, how to detect the concentration of phosphoric acid is an important issue.

The current detection method is performed by using an ion-selective electrode, such as "Phosphate ion selective electrode and manufacturing method thereof" in US Pat. No. 6,540,894, which uses a metal salt slightly soluble in water as a sensing film. A low concentration of phosphate ions can be measured; in addition, it can also be detected by a spectrophotometer or a liquid chromatography mass spectrometer, and the spectrophotometer is used to quantify phosphate by using the relationship between the absorbance and the concentration of the phosphate. The liquid chromatography mass spectrometer separates impurities through different columns, and then uses the spectral measurement of the separated liquid to conduct concentration analysis on the characteristic waveform of the phosphoric acid through different peak signals.

However, ion-selective electrodes and spectrophotometers have no specificity for phosphoric acid, are susceptible to other acids, and generate noise, causing misjudgment of concentration, while liquid chromatography mass spectrometers require longer processing times. It is not conducive to industrial utilization. Therefore, how to measure the concentration of phosphoric acid quickly and accurately is a problem that the relevant industry wants to solve.

The main object of the present invention is to solve the problem that the concentration of phosphoric acid cannot be measured quickly and accurately.

In order to achieve the above object, the present invention provides a method for fabricating a test strip, comprising the steps of: S1: forming a copper electrode on a first region of a substrate, the copper electrode comprising a working electrode, a reference electrode, and a An auxiliary electrode, the working electrode includes a first working end and a first reading end away from the first working end; S2: forming a first nickel layer on the first working end away from the side of the substrate; S3: utilizing Nickel immersion gold forms a first gold layer on the side of the first nickel layer away from the substrate; and S4: forming an insulating layer on a second region of the substrate adjacent to the first region The insulating layer covers the periphery of the first gold layer away from one side of the first nickel layer.

In addition, the present invention further provides a detection method for detecting a phosphoric acid concentration by using a test strip, which comprises the following steps: Q1: obtaining a redox potential of phosphoric acid by cyclic voltammetry, and according to different known concentrations The phosphoric acid aqueous solution establishes a reference ratio of the monophosphate concentration; Q2: obtains a mixed aqueous solution of the phosphoric acid mixed with an unknown concentration, and titrates the mixed aqueous solution onto the test piece; Q3: applying the redox potential to the test piece, Obtaining a current signal of the mixed aqueous solution; and Q4: comparing the current signal with the phosphoric acid concentration to compare the data to confirm the concentration of the phosphoric acid in the mixed aqueous solution.

In summary, the present invention has the following features:

1. By dropping the mixed aqueous solution onto the test piece and applying the redox potential to obtain the current signal, the concentration of phosphoric acid can be compared, and the method has the advantages of fastness and precision.

2. By covering the insulating layer with the periphery of the first gold layer away from the side of the first nickel layer, the exposure of the first nickel layer and the copper electrode can be prevented, thereby affecting the accuracy of measurement.

Third, the test strip is a low-cost disposable electrode, and the expensive instrument, such as a spectrophotometer or a liquid chromatography mass spectrometer, is not needed, and the cost can be reduced.

The detailed description and technical content of the present invention will now be described as follows:

Please refer to the "Fig. 1" to "Fig. 3F" to test the production method of the test piece. To further clarify, "Fig. 3A" to "Fig. 3F" are explained by using the AA cross section in Fig. 2, and The production method includes the following steps:

Step S1: forming a copper electrode 20 on a first region 11 of a substrate 10, as shown in FIG. 3A, the copper electrode 20 includes a working electrode 21, a reference electrode 22, and an auxiliary electrode 23, and The working electrode 21 includes a first working end 211 and a first reading end 212 away from the first working end 211. The method of forming the copper electrode 20 may be by screen printing, or a copper layer is first formed on the substrate 10, and then etched to form the copper electrode 20, but not limited thereto. In this embodiment, the following steps are further included:

Step S1A: The copper electrode 20 is formed prior to the first region 11 of the substrate 10.

Step S1B: as shown in FIG. 3B, an isolation layer 60 is formed on a second region 12 of the substrate 10, and the isolation layer 60 is in contact with the copper electrode 20, and the second region 12 is adjacent. In the first region 11, in the embodiment, the isolation layer 60 is formed thicker than the copper electrode 20, but the isolation layer 60 may be thinner than the copper electrode 20.

Step S2: As shown in FIG. 3C, a first nickel layer 31 is formed on the side of the first working end 211 away from the substrate 10, and the first nickel layer 31 is formed by electroless plating (Electroless plating). ) and other methods. In this embodiment, the following steps are further included:

Step S2A: forming the first nickel layer 31 away from the side of the substrate 10 at the first working end 211.

Step S2B: forming a second nickel layer 32 on one side of the second working end 221 of the reference electrode 22 away from the substrate 10, and the reference electrode 22 further includes a second reading away from the second working end 221 End 222.

Step S2C: forming a third nickel layer 33 on one side of the third working end 231 of the auxiliary electrode 23 away from the substrate 10. The first nickel layer 31, the second nickel layer 32, and the third nickel layer 33 may be formed at the same time, and the auxiliary electrode 23 further includes a third reading end 232 away from the third working end 231. Since the first reading end 212, the second reading end 222 and the third reading end 232 do not need to be in contact with the detecting liquid, it is not necessary to form a nickel layer thereon.

Step S3: As shown in FIG. 3D, a first gold layer 41 is formed by nickel immersion gold on the side of the first nickel layer 31 away from the substrate 10, and the nickel immersion gold is immersed in a low concentration. In the gold solution, gold is deposited on the first nickel layer 31 while the first nickel layer 31 is ejected, and the first gold layer 41 can be formed. In this embodiment, the following steps are further included:

Step S3A: forming the first gold layer 41 on a side of the first nickel layer 31 away from the substrate 10.

Step S3B: forming a second gold layer 42 away from one side of the substrate 10 at the end of the second nickel layer 32.

Step S3C: forming a third gold layer 43 away from one side of the substrate 10 at the end of the third nickel layer 33. The first gold layer 41, the second gold layer 42, and the third gold layer 43 can be simultaneously formed. After this step, the following steps are included:

Step P1: As shown in FIG. 3E, a second conductive layer 72 is formed on the side of the second gold layer 42 away from the substrate 10. The second conductive layer 72 may be made of silver, silver chloride or combination. The second conductive layer 72 can be formed by screen printing.

Step P2: forming a third conductive layer 73 on a side of the third gold layer 43 away from the substrate 10. The material of the third conductive layer 73 is carbon, platinum or a combination thereof. The third conductive layer 73 may be formed by screen printing.

Step S4: As shown in FIG. 3F, an insulating layer 50 is formed on the second region 12 adjacent to the first region 11 of the substrate 10, and the insulating layer 50 is upward from the second region 12. Extending and covering the periphery of the first gold layer 41 away from the side of the first nickel layer 31, thereby preventing the first nickel layer 31 and the copper electrode 20 from being exposed, thereby affecting the accuracy of measurement degree. In this embodiment, the insulating layer 50 is formed on the isolation layer 60, and the material of the insulating layer 50 and the isolation layer 60 may be the same as long as it does not react with other materials. However, as shown in FIG. 4, in other embodiments, the isolation layer 60 may not be formed, and the insulating layer 50 may be directly formed, such that the insulating layer 50 and the copper electrode 20, the first nickel layer 31, and the The periphery of the first gold layer 41 is in contact with, and also covers, the periphery of the first gold layer 41 away from the side of the first nickel layer 31.

In use, the liquid droplet is detected to the first working end 211, the second working end 221 and the third working end 231, and a detecting device (not shown) is connected to the first reading end 212, the first The second read end 222 and the third read end 232 can be measured.

Continued collocation Referring to "Fig. 5" to "Fig. 7", the concentration of phosphoric acid is measured for the test piece produced by the above method, and includes the following steps:

Step Q1: The redox potential of the phosphoric acid is obtained by cyclic voltammetry, and the reference ratio of the monophosphate concentration is established according to different known concentrations of the phosphoric acid aqueous solution. In this embodiment, the following steps are further included:

Step Q1A: The redox potential of the phosphoric acid is obtained by cyclic voltammetry (CV).

Step Q1B: formulating the aqueous phosphoric acid solutions of different known concentrations, and applying the redox potential to the aqueous phosphoric acid solutions by chronoamperometry to obtain a different current change according to the concentration of the aqueous phosphoric acid solutions. Phosphoric acid current response data, and phosphoric acid current response data as shown in Figure 6, the concentration of line A, line B, line C, line D, and line E are 0.003% wt, 0.03% wt, 0.15% wt, 0.3%, respectively. Wt, 0.9% wt.

Step Q1C: The phosphoric acid concentration reference alignment data is established based on the phosphoric acid current response data. Please refer to "Figure 6" for the appropriate time as a reference line, for example 2.5 seconds, and obtain the corresponding currents of the different concentrations of the phosphoric acid aqueous solution, and further make the current-to-concentration comparison data. The phosphoric acid concentration reference alignment data as shown in "Fig. 7" can be formed, and the linear correlation coefficient (R ² ) thereof is 0.9767, and therefore, it has a high accurate basis.

Step Q2: A mixed aqueous solution in which the phosphoric acid is mixed is obtained, the concentration of which is unknown, and the mixed aqueous solution is titrated onto the test piece.

Step Q3: applying the oxidation-reduction potential to the test piece to obtain a current signal of the mixed aqueous solution, and the oxidation-reduction potential of the phosphoric acid determined by cyclic voltammetry is 0.15 volt. In addition, when 0.14 volts or 0.16 volts is applied, the linear correlation coefficient (R ² ) is 0.2651 and 0.3014, respectively, so that it is known that when 0.15 volts is applied, the specificity of the detection phosphoric acid solution is good.

Step Q4: Align the current signal with the phosphoric acid concentration to confirm the concentration of the phosphoric acid in the mixed aqueous solution. With reference to "Figure 7", if the current signal is 20 μA, the concentration of phosphoric acid can be determined to be 0.22% by weight. In this way, the concentration of phosphoric acid can be measured quickly and accurately using this method (result signal RSD = 1.5% or less).

In summary, the present invention has the following features:

1. The current signal obtained by titrating the mixed aqueous solution onto the test piece and applying the oxidation-reduction potential can quickly and accurately measure the concentration of phosphoric acid.

2. By covering the insulating layer with the periphery of the first gold layer away from the side of the first nickel layer, the exposure of the first nickel layer and the copper electrode can be prevented, thereby affecting the accuracy of measurement.

Third, the test strip is a low-cost disposable electrode, and the expensive instrument, such as a spectrophotometer or a liquid chromatography mass spectrometer, is not required, and the cost can be reduced.

Therefore, the present invention is highly progressive and conforms to the requirements of the invention patent application, and the application is filed according to law, and the praying office grants the patent as soon as possible.

The present invention has been described in detail above, but the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the scope of the invention. That is, the equivalent changes and modifications made by the scope of the present application should remain within the scope of the patent of the present invention.

10‧‧‧Substrate
11‧‧‧First area
12‧‧‧Second area
20‧‧‧ copper electrode
21‧‧‧Working electrode
211‧‧‧ first working end
212‧‧‧First reading end
22‧‧‧ reference electrode
221‧‧‧Second working end
222‧‧‧second reading end
23‧‧‧Auxiliary electrode
231‧‧‧ Third working end
232‧‧‧ third read end
31‧‧‧First nickel layer
32‧‧‧Second nickel layer
33‧‧‧ Third nickel layer
41‧‧‧First gold layer
42‧‧‧Second gold layer
43‧‧‧ third gold layer
50‧‧‧Insulation
60‧‧‧Isolation
72‧‧‧Second conductive layer
73‧‧‧ Third conductive layer
S1~S4, S1A~S1C, S2A~S2C, S3A~S3C, P1, P2, Q1~Q4, Q1A~Q1C‧‧‧ steps
A~E‧‧‧ line segment

FIG. 1 is a schematic flow chart of a first embodiment of the present invention. Fig. 2 is a perspective view showing the structure of the first embodiment of the present invention. 3A-3F are schematic diagrams showing the manufacturing process of the first embodiment of the present invention. Figure 4 is a cross-sectional view showing a second embodiment of the present invention. FIG. 5 is a schematic flow chart of a third embodiment of the present invention. FIG. 6 is a schematic diagram of current response data according to a third embodiment of the present invention. FIG. 7 is a schematic diagram of data of concentration reference ratio data according to a third embodiment of the present invention.

Q1~Q4, Q1A~Q1C‧‧‧ steps

Claims (8)

A method for manufacturing a test strip comprises the following steps: S1: forming a copper electrode on a first region of a substrate, the copper electrode comprising a working electrode, a reference electrode and an auxiliary electrode, the working electrode comprising a first working end and a first reading end away from the first working end; S2: forming a first nickel layer away from the side of the substrate at the first working end; S3: forming by means of nickel immersion gold a first gold layer on a side of the first nickel layer away from the substrate; and S4: an insulating layer is formed on a second region of the substrate adjacent to the first region, the insulating layer covering the first layer A gold layer is away from the periphery of one side of the first nickel layer. The method for manufacturing a test strip according to claim 1, wherein in the step S1, the method further comprises the steps of: forming a copper electrode in the first region of the substrate; and S1B: on the substrate A second region forms an isolation layer that contacts the copper electrode. The method for manufacturing a test strip according to the first aspect of the invention, wherein in the step S2, the method further comprises the following steps: S2A: forming the first nickel layer at a side of the first working end away from the substrate; S2B: forming a second nickel layer on a side of the second working end of the reference electrode away from the substrate; and S2C: forming a third nickel layer on a side of the third working end of the auxiliary electrode away from the side of the substrate . The method for manufacturing a test strip according to claim 3, wherein in the step S3, the method further comprises the following steps: S3A: forming the first gold layer on a side of the first nickel layer away from the substrate; S3B: forming a second gold layer on a side of the second nickel layer away from the substrate; and S3C: forming a third gold layer on a side of the third nickel layer away from the substrate. The method for manufacturing a test strip according to the fourth aspect of the invention, wherein after the step S3, the method further comprises the following steps: P1: forming a second conductive layer on a side of the second gold layer away from the substrate, The material of the second conductive layer is selected from the group consisting of silver and silver chloride; and P2: forming a third conductive layer on a side of the third gold layer away from the substrate, the third conductive layer The material is selected from the group consisting of carbon and platinum. A method for detecting a phosphoric acid concentration by using a test piece according to claim 1 of the patent application, comprising the following steps: Q1: obtaining a redox potential of monophosphoric acid by cyclic voltammetry, and according to different known concentrations of phosphoric acid The aqueous solution establishes a reference ratio of the phosphoric acid concentration; Q2: obtaining a mixed aqueous solution of the phosphoric acid mixed with an unknown concentration, and titrating the mixed aqueous solution onto the test piece; Q3: applying the redox potential to the test piece to Obtaining a current signal of the mixed aqueous solution; and Q4: comparing the current signal with the phosphoric acid concentration to compare the data to confirm the concentration of the phosphoric acid in the mixed aqueous solution. The method for detecting the concentration of phosphoric acid as described in claim 6, wherein in step Q1, the method further comprises the steps of: Q1A: obtaining the redox potential of the phosphoric acid; Q1B: formulating the different known concentrations An aqueous phosphoric acid solution is applied to the phosphoric acid aqueous solution by a chronoamperometry method to obtain a phosphoric acid current response data according to the concentration of the phosphoric acid aqueous solution; and Q1C: according to the phosphoric acid current response data Establish the reference ratio of the phosphoric acid concentration. A method for detecting a phosphoric acid concentration as described in claim 6, wherein in the step Q1, the oxidation-reduction potential is 0.15 volt.