Application Of Indirect Sensing Strategy In Electrochemical And Colormetric Analysis

Electrochemical and colorimetric biosensors are the important part of biosensors that combined the sensing technology and biological detection principle of biological detection and have been widely used in medical sensing,environmental monitoring and food agriculture.In recent years,the indirect sensing strategy based on the electrochemical and colorimetric related reports have been emerged in an endless stream.In this paper,several electrochemical and colorimetric biosensor platforms based on indirect sensing strategies are designed and successfully applied to the analysis of life-related substances and environmental pollution monitoring.The main contents are as follows:1.The interaction between 1,2-naphthoquinone-4-sulfonic acid sodium salt(NQS)and sarcosine was stronger than that between NQS and Ru(NH3)63+ species.Indicator displacement assay was used to the principle of indirectly colorimetric sensor of the sarcosine,and the sensing mechanism of the colorimetric sensor was studied by UV-Vis spectroscopy,Fourier transform infrared spectroscopy and electrochemical technique.The indirect detection of sarcosine had more selective and sensitive compared with direct dection,such as the test paper detection.Furthermore,this paper also studied the application of the colorimetric sensor in molecular logic gates.2.The modified electrodes was prepared by the interaction between GO and NQS,NQS and Ru(NH3)63+ by using the indicator displacement assay(IDA)as an indirect electrochemical detection of sarcosine.The preparation and electrochemical sensing of the modified electrode were characterized by UV-Vis spectroscopy,scanning electron microscopy,energy spectrum,cyclic voltammetry and differential pulse voltammetry.Since the target can react with the NQS molecule and replace the Ru(NH3)63+ on the surface of the modified electrode,which affects the response current of the modified electrode.The electrochemical sensing of sarcosine was achieved by measuring the electrochemical signal of Ru(NH3)63+ under the condition of the presence of sarcosine.3.A new type of dual-Signalling electrochemical sensor about hydrogen peroxide was developed.The oxidation peak current of Ru(NH3)63+ decreases and that of Fe(CN)64-increase with the increase of the concentration of hydrogen peroxide.The feasibility of the sensor detection on the target was investigated by UV-Vis spectroscopy,electrochemical impedance spectroscopy and differential pulse voltammetry.The new electrochemical sensor uses two kinds of electrochemical signal(I = |△ IRu | + △ IFe)as the hydrogen peroxide concentration response signal,effectively improve the sensitivity of hydrogen peroxide detection.