A bioelectrochemical sensor and a method for detecting formaldehyde

Abstract

The application provides a bioelectrochemical sensor and a method for detecting formaldehyde. The bioelectrochemical sensor comprises a working electrode, a reference electrode, a counter electrode, a buffer solution and an aldehyde dehydrogenase solution. The application is based on selective electrochemical oxidation of formaldehyde by aldehyde dehydrogenase, and a bioelectrochemical sensor for detecting formaldehyde with high sensitivity and high selectivity is designed. The method for detecting formaldehyde provided by the application is simple to operate, does not require a large amount of preparation work in advance, and does not use expensive testing instruments. The method has high sensitivity, fast response to formaldehyde, wide detection range, low detection limit, high selectivity, high accuracy, good stability, simple storage, and strong repeatability.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of detection, and particularly relates to a bioelectrochemical sensor and a method for detecting formaldehyde. BACKGROUND

[0002] Formaldehyde is a major indoor air pollutant, which is harmful to human body.

[0003] The commonly used method for detecting formaldehyde is the phenol reagent method, and the main detection process is as follows: first, formaldehyde in the air is collected by absorbing the formaldehyde in the air through a phenol reagent solution, a chromogenic agent is added for color development, then the absorbance of the sample is tested by a spectrophotometer, and finally the corresponding formaldehyde concentration is calculated through a standard curve. This method has the problems of complex process, low sensitivity, and high minimum detection limit.

[0004] In addition, although the detection of formaldehyde has been widely concerned, various detection methods have been continuously developed, but the interference of volatile organic compounds (VOCs) still needs to be solved.

[0005] Therefore, how to provide a device for detecting formaldehyde and a method for detecting formaldehyde, so as to avoid the interference of volatile organic compounds (VOCs) and have high detection accuracy, has become a problem to be solved at present. SUMMARY

[0006] In view of the deficiencies of the prior art, the purpose of the present application is to provide a bioelectrochemical sensor and a method for detecting formaldehyde.

[0007] To achieve the purpose of the present application, the following technical solutions are adopted:

[0008] In the first aspect, the present application provides a bioelectrochemical sensor, which comprises a working electrode, a reference electrode, a counter electrode, a buffer solution and an aldehyde dehydrogenase solution.

[0009] In the present application, the working electrode comprises any one of a copper-based electrode, a Pt electrode, a Ti-based electrode, an Au-based electrode, an iron-based electrode, a nickel-based electrode or a carbon-based electrode, and is preferably a copper-based electrode.

[0010] In the present application, the reference electrode comprises any one of an Ag / AgCl electrode, a hydrogen electrode, a mercury-mercury electrode, a mercury-mercury oxide electrode or a mercury-mercury sulfite electrode, and is preferably an Ag / AgCl electrode.

[0011] In the present application, the counter electrode comprises any one of a Pt electrode, a carbon-based electrode, an Au-based electrode, a copper-based electrode, an iron-based electrode, a Ti-based electrode or a nickel-based electrode, and is preferably a Pt electrode.

[0012] In the present application, the buffer solution includes any one of PBS buffer solution, citric acid-sodium citrate buffer solution, sodium carbonate-sodium bicarbonate buffer solution, barbiturate buffer solution, ammonia-ammonium chloride buffer solution or borax-calcium chloride buffer solution, preferably PBS buffer solution.

[0013] In the present application, the aldehyde dehydrogenase includes any one of formaldehyde dehydrogenase, acetaldehyde dehydrogenase solution, 3-phosphoglyceraldehyde dehydrogenase or retinal dehydrogenase or a mixture of at least two of them, preferably acetaldehyde dehydrogenase.

[0014] In the present application, the pH of the buffer solution is 6-10 (for example, it can be 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, etc., but is not limited to the listed values, and other values not listed in the above value range are also applicable).

[0015] In the present application, the mass concentration of the aldehyde dehydrogenase solution is 0.025-0.5 mg / mL (for example, it can be 0.025 mg / L, 0.05 mg / L, 0.1 mg / L, 0.15 mg / L, 0.2 mg / L, 0.25 mg / L, 0.3 mg / L, 0.35 mg / L, 0.4 mg / L, 0.45 mg / L, 0.5 mg / L, etc., but is not limited to the listed values, and other values not listed in the above value range are also applicable).

[0016] In the second aspect, the present application provides a method for detecting formaldehyde, which uses the bioelectrochemical sensor of the first aspect to detect formaldehyde.

[0017] The present application is based on the selective electrochemical oxidation of formaldehyde by aldehyde dehydrogenase on the working electrode, and designs a high-sensitivity and high-selectivity formaldehyde detection method. The detection signal of the method shows a standard power law relationship with the analyte, with a wide detection range of 10 -1 ~ 10 -18 M, and a detection limit (LOD) of 1.46 x 10 -18 M, which is much lower than the safe exposure limit of formaldehyde (about 10 - 9 Compared with the traditional phenol reagent method, this electrochemical method based on aldehyde dehydrogenase has high specificity for formaldehyde in common volatile organic compounds (VOCs) such as benzene, toluene and xylene.

[0018] In the present application, the method includes the following steps: using the bioelectrochemical sensor to detect standard working solutions containing different concentrations of formaldehyde by cyclic voltammetry, constructing a standard curve according to the change relationship between the reduction peak current and the concentration of formaldehyde, and calculating the concentration of formaldehyde in the sample according to the standard curve.

[0019] The detection method provided by the application determines the formaldehyde concentration by converting the chemical signal of the chemical reaction into an electric signal, and the specific principle is that formaldehyde is converted into formic acid under the action of aldehyde dehydrogenase, and protons and electrons are generated in the process, the working electrode captures the electrons in the chemical reaction process and converts them into an electric signal, and then the concentration of formaldehyde is judged by the intensity of the electric signal.

[0020] Compared with the prior art, the application has the following beneficial effects:

[0021] (1) The application is based on the selective electrochemical oxidation of formaldehyde by aldehyde dehydrogenase, and designs a bioelectrochemical sensor for detecting formaldehyde with high sensitivity and high selectivity;

[0022] (2) The method for detecting formaldehyde provided by the application is simple to operate, and does not require a large amount of preparation work in advance and the use of expensive test instruments;

[0023] (3) The method for detecting formaldehyde provided by the application has high sensitivity and fast response to formaldehyde;

[0024] (4) The method for detecting formaldehyde provided by the application has a wide detection range, low detection limit, and can detect ultra-low concentration of formaldehyde;

[0025] (5) The method for detecting formaldehyde provided by the application has high selectivity and high accuracy, and is not affected by other volatile organic compounds;

[0026] (6) The method for detecting formaldehyde provided by the application has good stability, simple storage and strong repeatability. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 The schematic diagram of the bioelectrochemical sensor for detecting formaldehyde provided by the application.

[0028] Figure 2 The CV curve under different formaldehyde concentrations.

[0029] Figure 3 The standard curve diagram. DETAILED DESCRIPTION

[0030] The technical solutions of the application will be further described through specific embodiments. Those skilled in the art should understand that the embodiments are only used to help understand the application and should not be regarded as specific limitations on the application.

[0031] Example 1

[0032] The embodiment provides a bioelectrochemical sensor, which comprises a working electrode, a reference electrode, a counter electrode, a buffer solution and an aldehyde dehydrogenase solution.

[0033] The working electrode is copper foil, the reference electrode is Ag / AgCl, the counter electrode is a Pt electrode, the buffer solution is a PBS buffer solution with pH=8, and the aldehyde dehydrogenase solution is an acetaldehyde dehydrogenase solution with a concentration of 0.2 mg / mL.

[0034] Example 2

[0035] The present embodiment provides a bioelectrochemical sensor, which comprises a working electrode, a reference electrode, a counter electrode, a buffer solution, and an aldehyde dehydrogenase solution.

[0036] The working electrode is copper foil, the reference electrode is a calomel electrode, the counter electrode is a stainless steel electrode, the buffer solution is a PBS buffer solution with pH=6, and the aldehyde dehydrogenase solution is an acetaldehyde dehydrogenase solution with a concentration of 0.025 mg / mL.

[0037] Example 3

[0038] The present embodiment provides a bioelectrochemical sensor, which comprises a working electrode, a reference electrode, a counter electrode, a buffer solution, and an aldehyde dehydrogenase solution.

[0039] The working electrode is copper foil, the reference electrode is a hydrogen electrode, the counter electrode is an Au electrode, the buffer solution is a PBS buffer solution with pH=10, and the aldehyde dehydrogenase solution is an acetaldehyde dehydrogenase solution with a concentration of 0.5 mg / mL.

[0040] Example 4

[0041] The present embodiment provides a bioelectrochemical sensor, which is different from the one in Example 1 only in that the concentration of the acetaldehyde dehydrogenase solution is 0.01 mg / mL, and the other preparation methods are the same as those in Example 1.

[0042] Example 5

[0043] The present embodiment provides a bioelectrochemical sensor, which is different from the one in Example 1 only in that the concentration of the acetaldehyde dehydrogenase solution is 0.7 mg / mL, and the other preparation methods are the same as those in Example 1.

[0044] Example 6

[0045] The present embodiment provides a bioelectrochemical sensor, which is different from the one in Example 1 only in that the buffer solution is a PBS buffer solution with pH=5, and the other preparation methods are the same as those in Example 1.

[0046] Example 7

[0047] The present embodiment provides a bioelectrochemical sensor, which is different from the one in Example 1 only in that the buffer solution is a PBS buffer solution with pH=12, and the other preparation methods are the same as those in Example 1.

[0048] Example 8

[0049] This example provides a bioelectrochemical sensor, which is different from example 1 only in that the working electrode is replaced by a nickel foam, and other preparation methods are the same as example 1.

[0050] Example 9

[0051] This example provides a bioelectrochemical sensor, which is different from example 1 only in that the working electrode is replaced by a lead electrode, and other preparation methods are the same as example 1.

[0052] Example 10

[0053] This example provides a bioelectrochemical sensor, which is different from example 1 only in that the buffer solution is replaced by a barbital buffer solution with pH = 8, and other preparation methods are the same as example 1.

[0054] Example 11

[0055] This example provides a bioelectrochemical sensor, which is different from example 1 only in that the buffer solution is replaced by a tris buffer solution with pH = 8, and other preparation methods are the same as example 1.

[0056] Example 12

[0057] This example provides a bioelectrochemical sensor, which is different from example 1 only in that the acetaldehyde dehydrogenase solution is replaced by a formaldehyde dehydrogenase solution with the same concentration, and other preparation methods are the same as example 1.

[0058] Example 13

[0059] This example provides a bioelectrochemical sensor, which is different from example 1 only in that the acetaldehyde dehydrogenase solution is replaced by a fatty aldehyde dehydrogenase solution with the same concentration, and other preparation methods are the same as example 1.

[0060] Test Example One

[0061] CV curve test

[0062] Test method: cyclic voltammetry is used, and the bioelectrochemical sensor provided in example 1 is used to test different concentrations of formaldehyde standard working solution.

[0063] As Figure 1The diagram shows a schematic of the bioelectrochemical sensor for formaldehyde detection provided by this invention. As can be seen from the diagram, this invention is based on the selective electrochemical oxidation of formaldehyde by aldehyde dehydrogenases on the working electrode. The formaldehyde concentration is determined by converting the chemical signal of the chemical reaction into an electrical signal. Specifically, formaldehyde is converted into formic acid under the action of aldehyde dehydrogenases. During this process, protons and electrons are generated. The working electrode captures the electrons generated in the chemical reaction and converts them into an electrical signal. The intensity of the electrical signal is then used to determine the formaldehyde concentration.

[0064] like Figure 2 The figure shows the CV curves at different formaldehyde concentrations. As can be seen from the figure, in the detection method provided by this invention, the detection signal exhibits a standard power-law relationship with the analyte, and its detection range is as wide as 10. -1 ~10 -18 M, and the limit of detection (LOD) is 1.46 × 10⁻⁶. -18 M, far below the safe exposure limit for formaldehyde (approximately 10). -9 M). Compared with the traditional phenol reagent method, this electrochemical method based on aldehyde dehydrogenases has high specificity for formaldehyde among common volatile organic compounds (VOCs), such as benzene, toluene, and xylene.

[0065] Test Example 2

[0066] Standard curve plotting

[0067] Test method: Based on the CV curve obtained from test example 1, a standard curve was constructed by the relationship between the reduction peak current and the change in formaldehyde concentration. The formaldehyde concentration in the sample was calculated based on the standard curve.

[0068] Standard curve graph as follows Figure 3 The standard curve is y = 1.96 × x. 0.125 / (0.045+x 0.125 ), R 2 =0.9996.

[0069] Test Example 3

[0070] Recovery rate test

[0071] Test method: Using the bioelectrochemical sensors provided in Examples 1-13, standard curves of the reduction peak current versus formaldehyde concentration were obtained according to the CV curve test method in Example 1 and the standard curve plotting method in Example 2. Then, a concentration of 10... -9 For the formaldehyde standard working solution of M, calculate the corresponding recovery rate. Repeat the test 5 times for each bioelectrochemical sensor, take the average value, and calculate the corresponding RSD value.

[0072] The test results are shown in Table 1 below:

[0073] Table 1

[0074]

[0075]

[0076] From the data in Table 1, it can be seen that the detection method provided by the present application has excellent recovery rate and lower RSD value.

[0077] From the comparison of Example 1 and Examples 4-5, it can be seen that the concentration of aldehyde dehydrogenase solution will affect the detection result.

[0078] From the comparison of Example 1 and Examples 6-7, it can be seen that the pH value of the buffer solution will affect the detection result.

[0079] From the comparison of Example 1 and Examples 8-9, it can be seen that the selection of working electrode will affect the detection result.

[0080] From the comparison of Example 1 and Examples 10-11, it can be seen that the selection of buffer solution will affect the detection result.

[0081] From the comparison of Example 1 and Examples 12-13, it can be seen that the selection of aldehyde dehydrogenase solution will affect the detection result.

[0082] The applicant declares that the process method of the present application is illustrated by the above examples, but the present application is not limited to the above process steps, that is, it does not mean that the present application must rely on the above process steps to be implemented. The skilled in the art should understand that any improvement of the present application, equivalent replacement of the selected raw materials of the present application, addition of auxiliary ingredients, selection of specific methods, etc. fall within the protection scope and disclosure scope of the present application.

Claims

1. A bioelectrochemical sensor, characterized in that, The bioelectrochemical sensor comprises a working electrode, a reference electrode, a counter electrode, a buffer solution and an aldehyde dehydrogenase solution. The aldehyde dehydrogenase solution comprises any one of an acetaldehyde dehydrogenase solution, a 3-phosphoglycerylaldehyde dehydrogenase solution or a retinal dehydrogenase solution or a mixture of at least two thereof. The mass concentration of the aldehyde dehydrogenase solution is 0.025-0.5 mg / mL. Formaldehyde is converted into formic acid under the action of the aldehyde dehydrogenase, and protons and electrons are generated in the process, the working electrode captures the electrons in the chemical reaction process and converts them into an electrical signal, and then the concentration of formaldehyde is determined by the intensity of the electrical signal.

2. The bioelectrochemical sensor of claim 1, wherein, The working electrode comprises any one of a copper-based electrode, a Pt electrode, a Ti-based electrode, an Au-based electrode, an iron-based electrode, a nickel-based electrode or a carbon-based electrode.

3. The bioelectrochemical sensor of claim 2, wherein, The working electrode is a copper-based electrode.

4. The bioelectrochemical sensor of claim 1, wherein, The reference electrode comprises any one of an Ag / AgCl electrode, a hydrogen electrode, a mercury-mercury oxide electrode or a mercury-mercury sulfite electrode.

5. The bioelectrochemical sensor of claim 4, wherein, The reference electrode is an Ag / AgCl electrode.

6. The bioelectrochemical sensor of claim 1, wherein, The counter electrode comprises any one of a Pt electrode, a carbon-based electrode, an Au-based electrode, a copper-based electrode, an iron-based electrode, a Ti-based electrode or a nickel-based electrode.

7. The bioelectrochemical sensor of claim 6, wherein, The counter electrode is a Pt electrode.

8. The bioelectrochemical sensor of claim 1, wherein, The buffer solution comprises any one of a PBS buffer solution, a citric acid-sodium citrate buffer solution, a sodium carbonate-sodium bicarbonate buffer solution, a barbital buffer, an ammonia-ammonium chloride buffer or a borax-calcium chloride buffer.

9. The bioelectrochemical sensor of claim 8, wherein, The buffer solution is a PBS buffer solution.

10. The bioelectrochemical sensor of claim 1, wherein, The aldehyde dehydrogenase solution is an acetaldehyde dehydrogenase solution.

11. A method of detecting formaldehyde, characterized by, The bioelectrochemical sensor of any one of claims 1-10 is used for detecting formaldehyde.

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