Electrochemical sensor electrode for rapidly and simultaneously detecting lead and cadmium ions as well as preparation method and application of electrochemical sensor electrode

[0034](1) Preparation of BSA-GO cross-linked polymer: Weigh 50 mg of BSA powder and dissolve it in 50 mL of ultrapure water to form a 1 mg / mL BSA aqueous solution. Transfer 2 mL of the solution to a new EP tube for later use. Pipette 2 mL of aminated graphene oxide suspension with a concentration of 5 mg / mL and 100 μL of glutaraldehyde into the above-mentioned EP tube, and shake and mix quickly. Pipette 10 μL of the above mixed solution and drop it on the surface of the working electrode of SPCE, let it stand at room temperature for 60 min, and after the liquid is dry, wash and dry it with ultrapure water and ethanol to obtain the BSA-GO cross-linked polymer modified working electrode.

[0035] (2) Loading of flower-shaped bismuth tungstate: Weigh 50mg of bismuth tungstate powder, suspend it in 5mL ultrapure water, oscillate, and ultrasonically mix for 30min to make it evenly dispersed in the system. Add it dropwise to the surface of the working electrode of the above electro

[0039] An application of an electrochemical sensor in simultaneously detecting lead ions and cadmium ions, comprising the following steps:

[0040] (1) With the SPCE of the BSA-GO cross-linked polymer of the BSA-GO cross-linked polymer that is loaded with flower-shaped bismuth tungstate modified on the surface of the working electrode in Example 1 as the electrochemical sensor, it is connected with the electrochemical workstation, and the pH is 5.0 in acetic acid Add different concentrations of lead and cadmium ion solutions (concentrations of lead and cadmium ions are 2, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100ppb) in the salt buffer solution. Test square wave anodic stripping voltammetry (SWAV).

[0041] (2) Construct a linear regression equation according to the relationship between lead ion concentration, cadmium ion concentration and peak current change, and calculate the concentration of lead ion and cadmium ion in the solution to be tested according to the linear regression

[0046] Embodiment 3: Investigate the detection accuracy of the electrochemical sensor.

[0047] In order to further verify the detection effect of the electrochemical sensor in practical application in Example 1, the standard addition method or direct dilution method is now used to use the electrochemical sensor for target detection in actual samples (assay method with reference to Example 2), Perform recovery experiments.

[0048] (1) Adopt the electrochemical sensor in the embodiment 1 to detect respectively Pb in the polluted soil 2+ and Cd 2+ The specific steps are as follows: the soil sample is processed by the automatic graphite heating digestion method, the obtained digestion solution is left to stand, and the supernatant is taken to adjust the pH to 5.0 with acetate buffer. Sample (contains Pb 2+ and Cd 2+ ) with reference to Table 1 for the concentration of the target substance, and finally the electrochemical sensor of Example 1 is detected in the solution to be tes