Electrochemical Research And Determination Of Iodine

In this paper,cyclic voltammetry?CV?was used to modify the L-glutamic acid,L-histidine,glycine,L-tyrosine,L-methionine and graphene dispersion on the surface of glassy carbon electrodes.Poly L-glutamic acid graphene modified electrode?PLG-GO/GCE?,poly L-histidine graphene modified electrode?PLH-GO/GCE?,polyglycine graphene modified electrode?Gly-GO/GCE?,poly L-tyrosine graphene?PLT-GO/GCE?,poly L-methionine modified electrode?PLM/GCE?,and poly L-methionine graphene modified electrode?PLM-GO/GCE?were prepared.The prepared electrodes were characterized by electrochemical impedance spectroscopy?EIS?and scanning electron microscopy?SEM?.The electrochemical behavior of iodine was studied by cyclic voltammetry?CV?,differential pulse voltammetry?DPV?,linear stripping voltammetry?LSV?,and square wave stripping voltammetry?SWV?.The electrochemical reaction mechanism of iodine is discussed.A new method for the determination of iodine is established and applied to the detection of samples containing iodine ions.The result is satisfying.The main problems to be solved throughout the experimental research are:?1?selection and characterization of optimum conditions for poly L-glutamic acid graphene modified electrode?PLG-GO/GCE?,poly L-histidine graphene modified electrode?PLH-GO/GCE?,polyglycine graphene modified electrode?Gly-GO/GCE?,poly L-tyrosine graphene?PLT-GO/GCE?,poly L-methionine modified electrode?PLM/GCE?,and poly L-methionine graphene modified electrode?PLM-GO/GCE?;?2?explore the electrochemical behavior of iodine ions under modified electrodes such as PLG-GO/GCE,PLH-GO/GCE,Gly-GO/GCE,PLT-GO/GCE,GCE,PLM/GCE and PLM-GO/GCE;?3?selection of the best measurement conditions for iodine ions under modified electrodes such as PLG-GO/GCE,PLH-GO/GCE,Gly-GO/GCE,PLT-GO/GCE;?4?study on the mechanism of iodine ions under GCE,PLM/GCE and PLM-GO/GCE modified electrodes;?5?electrochemical behavior of iodine ion and ascorbic acid measured simultaneously under a Gly-GO/GCE modified electrode.The research focuses on the following parts:1.Preparation of PLG-GO/GCE,PLH-GO/GCE,Gly-GO/GCE,PLT-GO/GCE,PLM/GCE and PLM-GO/GCE modified electrodes using cyclic voltammetry?CV?.Scanning electron microscopy?SEM?characterization.Characterization of PLG-GO/GCE,PLH-GO/GCE,Gly-GO/GCE,PLT-GO/GCE modified electrodes using AC impedance.2.PLG-GO/GCE modified electrodes,PLH-GO/GCE modified electrode,Gly-GO/GCE modified electrode,and PLT-GO/GCE modified electrode were prepared using cyclic voltammetry.The cyclic voltammetry?CV?and differential pulse voltammetry?DPV?techniques were used to study and compare the electrochemical behavior of I^-under their respective optimal conditions.In the concentration range of 2.50×10^-66 to 1.00×10^-3mol/L,the PLH-GO/GCE modified electrode has a good linear relationship with the peak current,and the minimum detection limit is 7.50×10^-7mol/L,the linear range of I^-on Gly-GO/GCE modified electrode is 1.00×10^-61.00×10^-3mol/L,and the minimum detection limit is 5.00×10^-7mol/L.The linear range of on PLT-GO/GCE modified electrode was 5.00×10^-6to 1.00×10^-3mol/L,and the minimum detection limit was 1.00×10^-6mol/L.The method was used to determine I^-in samples with satisfactory results.3.An electrochemical analysis method for the determination of iodine was established using different types of electrodes:GCE,PLM/GCE,PLM-GO/GCE.When the differential pulse amperometric method is used to determine iodine,its concentration in the range of 1.00×10^-66 to 1.00×10^-3mol/L has a good linear relationship with the peak current.The minimum detection limit of iodine is 7.50×10^-77 mol/L,and the RSD was 2.4%.The use of different electrodes and different determination methods to detect iodine ions in seafood,the results are not significantly different,which is satisfactory.4.An electrochemical analysis method for the determination of iodine was established using different types of electrodes:GCE,PLM/GCE,PLM-GO/GCE.The electrochemical behavior of iodine under different pH conditions,different potential ranges and scan rates was studied in detail.The mechanism of iodine redox.5.Cyclic voltammetry?CV?and differential pulse voltammetry?DPV?are used to simultaneously determine the electrochemical behavior of iodine ions and ascorbic acid in solution.Gly-GO/GCE modified electrode was used as the working electrode,and the two-component substance was determined under the pH of 2.5 and the best experimental parameters.The minimum detection limit of I^-is 3.00×10^-6mol/L,and the minimum detection limit of ascorbic acid is 8.30×10^-7mol/L.