Electrochemical uric acid test strip and uric acid detection method

Abstract

The application provides an electrochemical uric acid test paper and a uric acid detection method. The electrochemical uric acid test paper has simple structure, low cost, easy manufacturing process, rapid reaction, sensitive detection, wide storage temperature, wide use temperature, wide effective period, accurate result, simple operation, etc. The uric acid detection method distinguishes the test current of ascorbic acid by different time and different excitation signals, subtracts the current signal of ascorbic acid from the current signal of uric acid and ascorbic acid, eliminates the interference of ascorbic acid, is simple to operate and low in cost, does not need to add other material components, does not need the participation of uric acid oxidase and ascorbic acid oxidase, directly distinguishes the current signal by different voltages, is short in test time, reduces the complex data correction process, maintains good repeatability of data, is simple in logic operation, basically has no influence on the repeatability of test signals, and can effectively remove the interference of ascorbic acid.

Description

Technical Field

[0001] This application relates to the field of in vitro diagnostic technology, and in particular to an electrochemical uric acid test strip and a method for uric acid detection. Background Technology

[0002] Uric acid is the final product of purine metabolism in the human body, and most uric acid can be excreted from the body through the kidneys in urine. However, with the continuous changes in people's work, lifestyle, and dietary structure, long-term unhealthy eating and living habits have led to an increase in the incidence of obesity, resulting in increased uric acid production and decreased excretion, forming hyperuricemia, which in turn leads to gout. Because gout medications have significant side effects, it is necessary for patients to continuously monitor their uric acid levels for better health, which can help with early prevention and treatment to some extent.

[0003] The main methods for determining uric acid include high performance liquid chromatography, chemiluminescence, and electrochemical methods. In the field of in vitro diagnostics (IVD), especially in point-of-care testing (POCT), electrochemical methods are widely used due to their advantages such as high sensitivity, short reaction time, and ease of operation.

[0004] Currently, electrochemical methods are mainly divided into enzymatic reaction methods and enzyme-free reaction methods. The use of enzymes increases the limitations on the storage temperature, usage temperature, and shelf life of test strips, and enzymes are relatively expensive. Without enzymes, some redox substances in body fluids can interfere with uric acid detection, such as ascorbic acid, dopamine, and levodopa, with ascorbic acid causing the most serious interference.

[0005] Ascorbic acid and uric acid coexist in body fluids. Both have reducing properties and similar molecular weights, structural characteristics, and oxidation potentials. Ascorbic acid interferes with the electrochemical detection of uric acid, greatly affecting the accuracy of the electrochemical detection results.

[0006] To reduce interference from redox substances, existing technologies include adding an anti-interference layer to the conventional test strip structure. When the sample passes through this layer, interfering substances (such as ascorbic acid) react with anti-interference enzymes (such as traditional ascorbic acid oxidase) within the layer, removing the interfering substances. The sample then proceeds to the reaction layer of the test strip to generate the corresponding electrical signal of the analyte. However, adding an anti-interference layer complicates the test strip structure, making mass production difficult and quality control challenging. Furthermore, the increased reagent content raises manufacturing costs, and the longer consumption time for ascorbic acid results in a longer timeframe for obtaining test results, leading to a poor user experience.

[0007] Existing technologies also employ multi-electrode modes (such as sensors with a three-electrode structure). When the background electrode current signal is obtained by reacting the anti-interference agent oxidase with the anti-interference agent, and the working electrode current signal is obtained by reacting the uric acid oxidase with uric acid, the uric acid detection value is obtained by correcting the working electrode current signal and the background electrode current signal. However, the current signal measured by using the enzyme electrode is greatly affected by other factors, and the current signal needs to undergo very complex data correction processing, which increases the uncertainty in the calculation process and leads to a decrease in the repeatability of the test signal. Furthermore, the multi-electrode working mode has a complex electrode structure and is not easy to manufacture.

[0008] Currently, there are three main methods to reduce and eliminate interference signals: First, using selective membranes as a physical method to remove large molecular interferences and reduce the interference signal; second, using low redox electron mediators to lower the oxidation potential and reduce the degree of oxidation of interferences on the electrode surface; and third, adding a dummy electrode to the electrochemical test strip and reducing the interference signal by directly subtracting the dummy electrode signal from the working electrode signal. Although these three methods can reduce or eliminate interference signals to some extent, the subtraction of interference signals will affect the measurement accuracy and stability of the electrochemical test strip. Summary of the Invention

[0009] The purpose of this application is to provide an electrochemical uric acid test strip and a uric acid detection method, which aims to solve the problems of complex structure, high cost, long detection time, and uncertain data processing in the existing electrochemical uric acid test strip.

[0010] To achieve the above objectives, this application provides an electrochemical uric acid test strip, comprising: a substrate, and a conductive layer and an electrode layer disposed on the substrate, wherein the electrode layer comprises a working electrode and a reference electrode, the working electrode is coated with a water-soluble oxidized electron mediator coating, and the water-soluble oxidized electron mediator does not participate in the chemical reaction when no voltage is applied to the working electrode.

[0011] Specifically, the water-soluble oxidative electron mediator does not undergo redox reactions with uric acid or interfering substances when no voltage is applied to the working electrode. However, the water-soluble oxidative electron mediator will undergo redox reactions with uric acid or interfering substances after a voltage is applied to the working electrode, thereby determining the amount of uric acid or interfering substances. Water-soluble oxidative electron mediators that can chemically react with uric acid or interfering substances without a voltage applied to the working electrode are not applicable to the scheme of this application.

[0012] Optionally, the water-soluble oxidative electron mediator includes any one of Meldora blue, organic dyes, phenazine electron mediators, and ferrocene and its derivatives.

[0013] In an optional embodiment, the electrode layer surface is coated with a multi-molecular polymer protective layer, the multi-molecular polymer including cellulose-based substances, the cellulose-based substances including: hydroxyethyl cellulose or hydroxypropyl methyl cellulose;

[0014] The electrode layer surface is also provided with a layer of double-sided adhesive.

[0015] In an optional embodiment, a hydrophilic film layer is provided on the double-sided adhesive, and pores are provided at the end of the hydrophilic film layer away from the sample application port.

[0016] This application also provides a method for detecting uric acid, using the above-mentioned electrochemical uric acid test strip, the detection method comprising:

[0017] A first excitation signal is applied to the working electrode to obtain a first current signal, wherein the voltage of the first excitation signal is greater than the oxidation potential of ascorbic acid and less than the oxidation potential of uric acid;

[0018] A second excitation signal is applied to the working electrode to obtain a second current signal, wherein the voltage of the second excitation signal is greater than the oxidation potential of the uric acid;

[0019] The uric acid current signal is obtained by subtracting the first current signal from the second current signal.

[0020] In one optional embodiment, the voltage range of the first excitation signal is 0.01-0.23V; and the voltage range of the second excitation signal is 0.23-0.80V.

[0021] Preferably, the voltage of the first excitation signal is 0.2V; the voltage of the second excitation signal is 0.35V.

[0022] In an optional embodiment, the durations of the first excitation signal and the second excitation signal are 0.01-1.00 s, respectively.

[0023] Preferably, the durations of the first excitation signal and the second excitation signal are both 0.5 seconds.

[0024] Preferably, before applying the first excitation signal to the working electrode, the method further includes:

[0025] The electrochemical uric acid test strip is used to draw the sample solution to be tested for 1 to 10 seconds, so that the sample to be tested is fully introduced into the sample application chamber of the electrochemical uric acid test strip.

[0026] Compared with the prior art, the beneficial effects of this application include:

[0027] The electrochemical uric acid test strip provided in this application has a working electrode coated with a water-soluble oxidative electron mediator coating. It does not require the addition of other substances, nor does it require the participation of uric acid oxidase and ascorbic acid oxidase. It has a simple structure, low cost, easy manufacturing process, rapid reaction, sensitive detection, wide storage temperature range, wide operating temperature range, relatively long shelf life, accurate results, and simple operation.

[0028] The uric acid detection method provided in this application distinguishes the test current of ascorbic acid by using different times and different excitation signals. By subtracting the current signal of ascorbic acid from the current signal of uric acid, the interference of ascorbic acid is eliminated. This uric acid detection method is simple to operate, low in cost, requires no additional substances, and does not require the participation of uric acid oxidase and ascorbic acid oxidase. It directly distinguishes the current signals by different voltages, has a short test time, reduces complex data correction processes, maintains good data repeatability, has simple logic operations, has virtually no impact on the repeatability of the test signal, and can effectively remove ascorbic acid interference. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation on the scope of this application.

[0030] Figure 1 This is a schematic diagram of the structure of the electrochemical uric acid test strip of this application;

[0031] Figure 2 This is a flowchart illustrating the uric acid detection method of this application.

[0032] Figure label:

[0033] 1-Substrate; 2-Wire layer; 3-Electrode layer; 4-Water-soluble oxidized electronic dielectric coating; 5-Double-sided adhesive; 6-Hydrophilic film layer; 601-Pore. Detailed Implementation

[0034] As used in this article:

[0035] "Prepared from" is synonymous with "comprising". The terms "comprising", "including", "having", "containing", or any other variations thereof as used herein are intended to cover non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such composition, step, method, article, or apparatus.

[0036] The conjunction "composed of..." excludes any unspecified elements, steps, or components. If used in a claim, this phrase makes the claim closed, excluding materials other than those described, except for associated conventional impurities. When the phrase "composed of..." appears in a clause of the body of a claim rather than immediately following it, it limits only the elements described in that clause; other elements are not excluded from the claim as a whole.

[0037] When a quantity, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pair of any upper or preferred value with any lower or preferred value, regardless of whether the range is disclosed individually. For example, when the range “1–5” is disclosed, the described range should be interpreted as including ranges “1–4”, “1–3”, “1–2”, “1–2 and 4–5”, “1–3 and 5”, etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include its endpoints and all integers and fractions within that range.

[0038] In these embodiments, unless otherwise specified, the portions and percentages are all by weight.

[0039] "Parts by mass" refers to the basic unit of measurement that expresses the mass ratio of multiple components. One part can represent any unit mass, such as 1g or 2.689g. If we say that component A has "a" parts by mass and component B has "b" parts by mass, it means the ratio of the mass of component A to the mass of component B is a:b. Alternatively, it can mean that the mass of component A is aK and the mass of component B is bK (K is any number representing a multiplier). It is important to understand that, unlike the number of parts by mass, the sum of the mass parts of all components is not limited to 100 parts.

[0040] "And / or" is used to indicate that one or both of the described situations may occur, for example, A and / or B includes (A and B) and (A or B).

[0041] This application provides an electrochemical uric acid test strip; please refer to [link / reference]. Figure 1 , Figure 1 The image shown is an exploded view of the electrochemical uric acid test strip of this application. The electrochemical uric acid test strip includes: a substrate 1, and a conductive layer 2 and an electrode layer 3 disposed on the substrate 1. The electrode layer 3 includes a working electrode and a reference electrode. The working electrode is coated with a water-soluble oxidized electron mediator coating 4, and the water-soluble oxidized electron mediator does not participate in the chemical reaction when no voltage is applied to the working electrode.

[0042] The substrate 1 is made of a stable, non-conductive material, such as PVC or PET.

[0043] Electrode layer 3 and conductive layer 2 are disposed on substrate 1, and can be disposed on substrate 1 by printing. Conductor layer 2 has two lead wire terminals, and the working electrode and reference electrode are respectively connected to the two terminals to achieve electrical connection.

[0044] The conductor layer 2 can be made of commonly used conductive materials, such as silver, gold, platinum, or carbon, or a mixture of at least two materials.

[0045] The reference electrode is a silver and / or silver chloride coating. For example, the reference electrode can be a silver electrode, a silver chloride electrode, or an electrode made of a mixture of silver and silver chloride. In this application, the reference electrode is preferably an electrode made of a mixture of silver and silver chloride.

[0046] The surface of electrode layer 3 is coated with a multi-molecular polymer protective layer, the multi-molecular polymer including cellulose-based substances, the cellulose-based substances including hydroxyethyl cellulose or hydroxypropyl methyl cellulose.

[0047] A layer of double-sided adhesive 5 is also provided on the surface of the electrode layer 3. A notch is made on the double-sided adhesive 5, and the double-sided adhesive 5 is pasted on the electrode layer 3. The thickness of the double-sided adhesive 5 is preferably 0.125mm.

[0048] A hydrophilic membrane layer 6 is provided on the double-sided tape 5. At the end of the hydrophilic membrane layer 6 away from the sample application port, there is an air hole 601, thereby forming a siphon channel. The siphon channel uses capillary action to draw the sample to be tested from the siphon port into the siphon channel, and the siphon channel guides the sample to be tested to the working electrode and the counter electrode.

[0049] The working electrode of this electrochemical uric acid test strip contains a water-soluble oxidized electron mediator that reacts with uric acid and ascorbic acid upon application of voltage. The reactions after voltage application are as follows: uric acid + oxidized electron mediator → allantoin + reducing electron mediator; ascorbic acid + oxidized electron mediator → dehydroascorbic acid + reducing electron mediator. The reactions do not require the participation of uric acid oxidase and ascorbic acid oxidase. The oxidized electron mediator directly oxidizes uric acid to produce allantoin and oxidizes ascorbic acid to produce dehydroascorbic acid. Silver and silver chloride reference electrodes provide the relative electrode reactions, forming a current loop. The concentrations of the reducing substances uric acid and ascorbic acid in the solution are calculated by measuring the current intensity.

[0050] Since both ascorbic acid and uric acid are reducing substances, and the oxidation potential of ascorbic acid is lower than that of uric acid, ascorbic acid is more easily oxidized. Therefore, by first providing a low oxidation potential to oxidize only ascorbic acid, and then providing a high oxidation potential to oxidize both uric acid and ascorbic acid, the uric acid value after eliminating the influence of ascorbic acid can be obtained by subtraction.

[0051] The active ingredient of the electrochemical uric acid test strip provided by this application is only a water-soluble oxidized electron mediator coating, without adding other substance components, without the participation of uricase and ascorbic acid oxidase, with a simple structure, low cost, easy production process, rapid reaction, sensitive detection, wide storage temperature range, wide use temperature range, wide expiration date, accurate results, and simple operation.

[0052] Optionally, the water-soluble oxidized electron mediator includes any one of Meldola blue, organic dyes, phenazine electron mediators, or ferrocene and its derivatives. In the electrochemical detection, the water-soluble oxidized electron mediator does not participate in chemical reactions when no voltage is applied to the working electrode.

[0053] This application also provides a method for detecting uric acid, using the above-mentioned electrochemical uric acid test strip. Please refer to Figure 2 , and the detection method includes:

[0054] S10: Apply a first excitation signal V1 to the working electrode to obtain a first current signal. The voltage of the first excitation signal V1 is greater than the oxidation potential of ascorbic acid and less than the oxidation potential of uric acid.

[0055] Apply a lower first excitation signal V1 to the working electrode. The voltage of this first excitation signal V1 is higher than the oxidation potential of ascorbic acid and lower than the oxidation potential of uric acid, Vascorbic acid < V1 < Vuric acid. Under the treatment of the first excitation signal V1, the first current signal I1 corresponding to the ascorbic acid concentration can be obtained.

[0056] In a preferred embodiment, the voltage range of the first excitation signal V1 is 0.01 - 0.23V, preferably the voltage of the first excitation signal V1 is 0.2V, and the duration of the first excitation signal V1 is 0.01 - 1.00S, preferably the duration is 0.5s.

[0057] S20: Apply a second excitation signal V2 to the working electrode to obtain a second current signal. The voltage of the second excitation signal V2 is greater than the oxidation potential of the uric acid.

[0058] After obtaining the first current signal I1, a relatively high second excitation signal V2 is immediately applied to the working electrode. The voltage of the second excitation signal V2 is higher than the oxidation potentials of uric acid and ascorbic acid, where Vascorbic acid < Vuric acid < V2. Under the signal processing of the second excitation signal V2, the sum of the current signal corresponding to the uric acid concentration and the current signal corresponding to the ascorbic acid concentration, i.e., the second current signal I2, can be obtained.

[0059] In a preferred embodiment, the voltage range of the second excitation signal V2 is 0.23 - 0.80 V, and preferably the voltage of the second excitation signal V2 is 0.35 V; the duration of the second excitation signal V2 is 0.01 - 1.00 S, and preferably the duration is 0.5 s.

[0060] S30: The current signal of the uric acid is obtained by subtracting the first current signal from the second current signal.

[0061] The current signal of the uric acid with the interference of ascorbic acid eliminated is obtained by subtracting the first current signal I1 measured by the first excitation signal V1 from the second current signal I2 measured by the second excitation signal V2.

[0062] Preferably, before applying the first excitation signal to the working electrode, it further includes:

[0063] The electrochemical uric acid test strip is used to absorb the sample solution to be detected for 1 - 10 S, preferably 3 S, so that the sample to be detected fully enters the sample addition cavity of the electrochemical uric acid test strip.

[0064] The uric acid detection method provided by this application separates the test currents of ascorbic acid through different times and different excitation signals. By subtracting the current signals of uric acid and ascorbic acid from the current signal of ascorbic acid, the interference of ascorbic acid is eliminated. This uric acid detection method is simple to operate, low in cost, does not require the addition of other substance components, does not require the participation of uricase and ascorbate oxidase, directly separates the current signals through different voltages, has a short test time, reduces the complex data correction process, maintains good repeatability of the data, has a relatively simple logical operation, has basically no influence on the repeatability of the test signals, and can effectively remove the interference of ascorbic acid.

[0065] The following will describe the implementation scheme of this application in detail with specific embodiments. However, those skilled in the art will understand that the following embodiments are only used to illustrate this application and should not be regarded as limiting the scope of this application. For those not specified in the embodiments, they are carried out according to the conventional conditions or the conditions recommended by the manufacturer. For the reagents or instruments not specified by the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0066] Example 1

[0067] The working electrode of the electrochemical uric acid test strip in Example 1 is coated with 0.1 wt% Meldora blue, a water-soluble oxidized electron mediator. 0.1 g of the 0.1 wt% Meldora blue water-soluble oxidized electron mediator was dissolved in 30 g of organic solvent to prepare a solution, which was then thoroughly stirred with 270 g of carbon ink. The ink was then screen-printed onto the test strip substrate. The organic solvent used was a mixed solvent, specifically comprising 65 wt% isophorone, 20 wt% xylene, and 15 wt% butyl acetate.

[0068] Blood samples with a hematocrit (Hct) of 42% and a uric acid (UA) concentration of 0.3 mmol / L were divided into five equal portions as samples 1, 2, 3, 4, and 5. Ascorbic acid was added to the samples to make the ascorbic acid concentrations in the five samples 0 mg / dL, 1.5 mg / dL, 3.0 mg / dL, 4.5 mg / dL, and 6 mg / dL, respectively.

[0069] The uric acid detection method in Example 1 includes:

[0070] 1. First, do not apply voltage to the electrode for 2 seconds to allow blood to fully enter the sample application chamber and remain stable.

[0071] 2. Apply a voltage signal of 0.2V to the working electrode and detect the current signal I1 0.5S after applying V1.

[0072] 3. Immediately increase the voltage to 0.35V and detect the current signal I2 0.5S after applying V2.

[0073] 4. Each sample was tested 5 times, and the current signal of uric acid that eliminates the interference of ascorbic acid was calculated as I2-I1.

[0074] 5. Calculate the mean, standard deviation, and coefficient of variation after step 4, and calculate the deviation from I2-I1 when the ascorbic acid concentration is 0.

[0075] The uric acid detection results of Example 1 are shown in Table 1. The repeatability of the test current is good, and the interference of ascorbic acid is greatly reduced, so that the interference of ascorbic acid concentrations of 1.5 mg / dl, 3 mg / dl, 4.5 mg / dl and 6 mg / dl is controlled within 4%.

[0076] Table 1. Uric acid test results of Example 1

[0077]

[0078]

[0079] Example 2

[0080] The working electrode of the electrochemical uric acid test strip in Example 2 is coated with ferrocene carboxylic acid as a water-soluble oxidized electron mediator. The structure of other electrochemical uric acid test strips is the same as that in Example 1. The samples tested in Example 2 are also the same as those in Example 1, and will not be described again here.

[0081] The uric acid detection method in Example 2 includes:

[0082] 1. First, do not apply voltage to the electrode for 2 seconds to allow blood to fully enter the sample application chamber and remain stable.

[0083] 2. Apply a voltage signal of 0.2V to the working electrode and detect the current signal I1 0.5S after applying V1.

[0084] 3. Immediately increase the voltage to 0.35V and detect the current signal I2 0.5S after applying V2.

[0085] 4. Each sample was tested 5 times, and the current signal of uric acid that eliminates the interference of ascorbic acid was calculated as I2-I1.

[0086] 5. Calculate the mean, standard deviation, and coefficient of variation after step 4, and calculate the deviation from I2-I1 when the ascorbic acid concentration is 0.

[0087] The uric acid detection results of Example 2 are shown in Table 2. The repeatability of the test current is very good, and the interference of ascorbic acid is greatly reduced, so that the interference of ascorbic acid concentrations of 1.5 mg / dl, 3 mg / dl, 4.5 mg / dl and 6 mg / dl is controlled within 4%.

[0088] Table 2. Uric acid test results of Example 2

[0089]

[0090] Comparative Example 1

[0091] The electrochemical uric acid test strip and sample of Comparative Example 1 are the same as those of Example 1. The difference between Comparative Example 1 and Example 1 is that the uric acid detection method of Comparative Example 1 includes:

[0092] 1. First, do not apply voltage to the electrode for 2.5 seconds to allow blood to fully enter the sample application chamber and remain stable.

[0093] 2. Apply a voltage signal of 0.35V to the working electrode and detect the current signal I2 0.5S after applying V2.

[0094] 3. Each sample was tested 5 times, and the current was recorded at the 3.0s mark of the test.

[0095] 4. Calculate the mean, standard deviation, and coefficient of variation for the same sample, and calculate the deviation from the value of 0 ascorbic acid.

[0096] The uric acid test results of Comparative Example 1 are shown in Table 3. According to the results in Table 3, when the samples containing ascorbic acid concentrations of 1.5 mg / dl, 3 mg / dl, 4.5 mg / dl, and 6 mg / dl were tested using a single voltage test, the test current increased by 21.9%, 43.2%, 60.7%, and 81.2% respectively compared to the test current containing 0 mg / dl ascorbic acid concentration, indicating a significant increase in interference from ascorbic acid.

[0097] Table 3 shows the uric acid test results for Comparative Example 1.

[0098]

[0099] Comparative Example 2

[0100] The electrochemical uric acid test strip and sample of Comparative Example 2 are the same as those of Example 2. The difference between Comparative Example 2 and Example 2 is that the uric acid detection method of Comparative Example 2 includes:

[0101] 1. First, do not apply voltage to the electrode for 2.5 seconds to allow blood to fully enter the sample application chamber and remain stable.

[0102] 2. Apply a voltage signal of 0.35V to the working electrode and detect the current signal I2 0.5S after applying V2.

[0103] 3. Each sample was tested 5 times, and the current was recorded at the 3.0s mark of the test.

[0104] 4. Calculate the mean, standard deviation, and coefficient of variation for the same sample, and calculate the deviation from the value of 0 ascorbic acid.

[0105] The uric acid test results for Comparative Example 2 are shown in Table 4. According to the results in Table 4, when using a single voltage test to detect samples containing ascorbic acid concentrations of 1.5 mg / dl, 3 mg / dl, 4.5 mg / dl, and 6 mg / dl, the test current increased by 18.6%, 36.3%, 52.1%, and 72.0% respectively compared to the test current containing 0 mg / dl ascorbic acid concentration, indicating a significant increase in interference from ascorbic acid.

[0106] Table 4. Uric acid test results of Comparative Example 2

[0107]

[0108]

[0109] Comparative Example 3

[0110] The working electrode of the electrochemical uric acid test strip in Comparative Example 3 is coated with potassium ferricyanide as the electron mediator. The structures of other electrochemical uric acid test strips are the same as those in Example 1. The samples tested in Comparative Example 3 are also the same as those in Example 1, and will not be described again here.

[0111] The uric acid detection methods in Comparative Example 3 include:

[0112] 1. First, do not apply voltage to the electrode for 2.5 seconds to allow blood to fully enter the sample application chamber and remain stable.

[0113] 2. Apply a voltage signal of 0.35V to the working electrode and detect the current signal I2 0.5S after applying V2.

[0114] 3. Each sample was tested 5 times, and the current was recorded at the 3.0s mark of the test.

[0115] 4. Calculate the mean, standard deviation, and coefficient of variation for the same sample, and calculate the deviation from the value of 0 ascorbic acid.

[0116] The uric acid test results for Comparative Example 3 are shown in Table 5. The test current of samples containing ascorbic acid concentrations of 1.5 mg / dl, 3 mg / dl, 4.5 mg / dl, and 6 mg / dl increased by 17.6%, 31.8%, 53.6%, and 72.9%, respectively, compared to the test current containing 0 mg / dl ascorbic acid concentration, indicating a significant increase in interference from ascorbic acid.

[0117] Table 5 shows the uric acid test results for Comparative Example 3.

[0118]

[0119]

[0120] Comparative Example 4

[0121] The electrochemical uric acid test strips and samples in Comparative Example 4 were the same as those in Comparative Example 3. The difference between Comparative Example 4 and Comparative Example 3 was that the uric acid detection method in Comparative Example 4 included:

[0122] 1. First, do not apply voltage to the electrode for 2 seconds to allow blood to fully enter the sample application chamber and remain stable.

[0123] 2. Apply a voltage signal of 0.2V to the working electrode and detect the current signal I1 0.5S after applying V1.

[0124] 3. Immediately increase the voltage to 0.35V and detect the current signal I2 0.5S after applying V2.

[0125] 4. Each sample was tested 5 times, and the current signal of uric acid that eliminates the interference of ascorbic acid was calculated as I2-I1.

[0126] 5. Calculate the mean, standard deviation, and coefficient of variation after step 4, and calculate the deviation from I2-I1 when the ascorbic acid concentration is 0.

[0127] The uric acid test results for Comparative Example 4 are shown in Table 6. The test current of samples containing ascorbic acid concentrations of 1.5 mg / dl, 3 mg / dl, 4.5 mg / dl, and 6 mg / dl increased by 20.6%, 44.3%, 48.1%, and 79.1%, respectively, compared to the test current containing 0 mg / dl ascorbic acid concentration, indicating a significant increase in interference from ascorbic acid.

[0128] The experimental results of Comparative Examples 3 and 4 show that although potassium ferricyanide is a water-soluble oxidizing electron mediator, due to its strong oxidizing properties, when it encounters reducing substances such as uric acid or ascorbic acid in the electrochemical test strip without a voltage applied to the working electrode, it will react with uric acid to form urea sac and K4Fe(CN)6, and react with ascorbic acid to form [Fe(CN)6]. 4- H2O, N2 and 2H + This leads to the consumption of uric acid and ascorbic acid, affecting the accuracy of electrochemical test strip detection. Therefore, if some water-soluble oxidizing electron mediators undergo redox reactions with the analyte or interfering substances before the electrochemical reaction process, the interference of ascorbic acid cannot be eliminated even with the detection method of this application.

[0129] Table 6 shows the uric acid test results for Comparative Example 4.

[0130]

[0131] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

[0132] Furthermore, those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of this application and form different embodiments. For example, in the foregoing claims, any of the claimed embodiments can be used in any combination. The information disclosed in this background section is intended only to enhance the understanding of the general background of this application and should not be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

Claims

1. A method for detecting uric acid, characterized in that, The uric acid test strips were used for detection. The electrochemical uric acid test strip includes: a substrate, and a wire layer and an electrode layer disposed on the substrate. The electrode layer includes a working electrode and a reference electrode. The working electrode is coated with a water-soluble oxidized electron mediator coating, and the water-soluble oxidized electron mediator does not participate in the chemical reaction when no voltage is applied to the working electrode. The electrode layer surface is coated with a multi-molecular polymer protective layer, the multi-molecular polymer including cellulose-based substances, the cellulose-based substances including: hydroxyethyl cellulose or hydroxypropyl methyl cellulose; The electrode layer surface is also provided with a layer of double-sided adhesive; The double-sided adhesive tape has a hydrophilic film layer, and the end of the hydrophilic film layer away from the sample application port has pores. The detection method includes: A first excitation signal is applied to the working electrode to obtain a first current signal, wherein the voltage of the first excitation signal is greater than the oxidation potential of ascorbic acid and less than the oxidation potential of uric acid; A second excitation signal is applied to the working electrode to obtain a second current signal, wherein the voltage of the second excitation signal is greater than the oxidation potential of the uric acid; The uric acid current signal is obtained by subtracting the first current signal from the second current signal.

2. The uric acid detection method according to claim 1, characterized in that, The water-soluble oxidative electron mediators include any one of Meldora blue, organic dyes, phenazine electron mediators, and ferrocene and its derivatives.

3. The uric acid detection method according to claim 1, characterized in that, The voltage range of the first excitation signal is 0.01-0.23V; the voltage range of the second excitation signal is 0.23-0.80V.

4. The uric acid detection method according to claim 3, characterized in that, The voltage of the first excitation signal is 0.2V; the voltage of the second excitation signal is 0.35V.

5. The uric acid detection method according to claim 1, characterized in that, The durations of the first excitation signal and the second excitation signal are 0.01-1.00 s, respectively.

6. The uric acid detection method according to claim 5, characterized in that, The durations of the first excitation signal and the second excitation signal are both 0.5 seconds.

7. The uric acid detection method according to claim 1, characterized in that, Before the first excitation signal is applied to the working electrode, the following is also included: The electrochemical uric acid test strip is used to draw the sample solution to be tested for 1-10 seconds, so that the sample to be tested is fully introduced into the sample application chamber of the electrochemical uric acid test strip.

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