| Based on the innovative design and optimal implementation of the surface modification method of glassy carbon electrode,the electrochemical reduction graphene oxide modified electrode was prepared by a simple potentiostatic reduction method using graphene oxide modified electrode as template with the objective of low fixative load,good catalytic performance,simple operation and no secondary pollution.Using the electrochemical reduction graphene oxide modified electrode as template,the glassy carbon electrode was modified by electrostatic adsorption and intermolecular force such as impregnated silver nanoparticles and electropolymerized L-methionine,and the electroreduced silver nanoparticles graphene composite film modified electrode and the poly L-methionine electroreduced silver nanoparticles graphene composite film modified electrode were prepared.The morphology of them were observed by scanning electron microscopy?SEM?,the electrochemical properties of them were characterized by cyclic voltammetry?CV?,and differential pulse voltammetry?DPV?was used to explore the feasibility of simultaneous detecting the mixture of three kinds of benzenediol isomers and detecting antibiotic ciprofloxacin hydrochloride and sulfonamide contaminants in water:I.Preparation of the electrochemical reduction graphene oxide modified electrode and simultaneous determination of benzenediol isomersElectrochemical reduced graphene oxide modified electrode RGO/GCE was prepared by simple constant potentiometric reduction using graphene oxide modified electrode as template,and the experimental conditions were optimized gradually to simultaneous detection of three benzenediol isomers under optimal conditions in the same solution.The results indicated that RGO/GCE can be used to simultaneously detect the three kinds of isoforms of benzenediol,the potential difference between hydroquinone?HQ?and catechol?CT?inRGO/GCE is 141.29 mV,and 323.81 mV between catechol and resorcinol?RS?,all three compounds HQ?CT and RS detected at the same time can be implemented and are satisfied with the concentration range of 5.00×10-62.00×10-4?5.00×10-62.00×10-44 and7.00×10-63.00×10-4mol/L,as well as the detection limits of 3.57×10-7?3.62×10-7and3.55×10-66 mol/L?S/N=3?.The preparation electrode was applied to detect the content of three kinds of benzenediol isomers in simulated water samples.II.Preparation of the electroreduced silver nanoparticles graphene composite film modified electrode and determination of ciprofloxacin hydrochlorideUsing the RGO/GCE as template,electroreduced silver nanoparticles graphene composite film modified electrode?AgNPs/RGO/GCE?was prepared by impregnation and electrochemical reduction method,the electrochemical behavior of ciprofloxacin hydrochloride?CIP?on AgNPs/RGO/GCE electrode was investigated,and the feasibility of detecting CIP with AgNPs/RGO/GCE electrode was explored on the basis.The results indicated that AgNPs/RGO/GCE has a very obvious catalytic effect for the electrochemical oxidation of CIP,the method has high sensitivity,good repeatability and stability under the optimal experimental conditions,the oxidation peak current for CIP increased linearly in the range of 5.00×10-73.00×10-44 mol/L,the regression equation is:I??A?=0.2177c+32.595??mol/L?,R=0.9989,with the detection limit of 1.52×10-77 mol/L?S/N=3?,the recoveries got by standard addition method of simulated water sample was 96.3%107.2%,and RSD was 2.015%3.342%.III.Preparation of the poly L-methionine electroreduced silver nanoparticles graphene composite film modified electrode and its applicationBased on the AgNPs/RGO/GCE,the poly L-methionine electroreduced silver nanoparticles graphene composite film modified electrode PLM/AgNPs/RGO/GCE was prepared by electropolymerization,and the experimental conditions were optimized gradually to detecting antibiotic ciprofloxacin hydrochloride and sulfonamide?SA?and simultaneous detecting the mixture of three kinds of benzenediol isomers contaminants in water.The concentration range under the optimal experimental conditions is 1.00×10-62.00×10-44 mol/L,the regression equation is:I??A?=0.4894c+24.164??mol/L?,R=0.9996,with the detection limit of 7.57×10-77 mol/L?S/N=3?,the recoveries got by standard addition method of simulated water sample was 99.56%100.4%,and RSD was 1.985%.The potential difference between HQ and CT is 120.64 mV,and 336.51 mV between CT and RS,the concentration range of the three compounds HQ?CT and RS are 5.00×10-73.00×10-4mol/L?5.00×10-73.00×10-4mol/L and 8.00×10-73.00×10-4mol/L,as well as the detection limits of 5.00×10-77 mol/L?5.00×10-77 mol/L and 8.00×10-77 mol/L?S/N=3?,the recoveries got by standard addition method of simulated water sample were 99.24%106.6%,RSD were 1.879%2.228%.The range of CIP is 7.00×10-81.00×10-44 mol/L,the regression equation is:I??A?=0.3721c+33.381??mol/L?,R=0.9996,with the detection limit of 7.00×10-8mol/L?S/N=3?,the recoveries got by standard addition method of simulated water sample was 99.75%100.3%,and RSD was 1.936%. |
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