Electrochemical Enzyme Biosensors Based On Gold Nanoparticles For Detection Of Organophosphorus Pesticides

Organophosphorus pesticides?OPs?can cause environmental pollution to water,air,agricultural products,soil,and negatively affect human health.Hence,it is essential to develop sensitive,ten-cent and simple methods for the detection of OPs.The acetylcholinesterase?AChE?electrochemical biosensors due to their simple preparation procedures,rapid response and high sensitivity have been aroused more and more attention.The application of nanomaterials for biosensors is the trendy method to improve the performance of biosensors.In this paper,two kinds of AChE biosensors with rapid,sensitive and accurate were constructed by using high performance of gold nanoparticles?AuNPs?and three-dimensional graphene.Using an ionic layer-by-layer self-assembly technique,colloidal gold nanoparticles and diazo-resins?DAR?were immobilised on the surface of a p-aminobenzenesulfonic acid-modified glassy carbon electrode to form a matrix composite membrane for acetylcholinesterase immobilisation.The electrochemical biosensor for the detection of OPs wasconstructedbasedonmatrixcompositemembraneofP-ABSA/DAR/AuNPs/DAR/AChE.TheelectrochemicalpropertiesofP-ABSA/DAR/AuNPs/DAR/AChE were investigated by electrochemical impedance spectroscopy and cyclic voltammetry.Under the optimal conditions,the electrochemical test results showed that the biosensor exhibited high sensitivity in the range of linear concentration from 1.0×10^-12 to 1.0×10^-8 g L^-1 with the detection limit of 5.12×10^-13and 5.85×10^-1313 g L^-11 for malathion and methyl parathion,respectively.The average recovery within 95-106%for detection of OPs in real water and vegetable samples indicated that the AChE biosensor had excellent potential for practical application.More importantly,photo-sensitive DAR was used as the assembly interlayer to convert the ionic bond into covalent bond,which improved stability of the biosensor.An another novel AChE biosensor for the detection of OPs was developed based on a film of gold nanoparticles/three-dimensional graphene?denoted as AuNPs/rGO?.This AuNPs/rGO film was prepared by the electroless plating of AuNPs on three-dimensio na l graphene.The electrochemical properties of P-ABSA/DAR/AuNPs/DAR/AChE were investigated by electrochemical measure.Under the optimal conditions,the electrochemica l test results showed that the AChE biosensor exhibited high sensitivity in the range of linear concentration from 1.0×10^-10 to 1.0×10^-6 g L^-1 with the detection limit of 2.78×10^-11and 2.17×10^-1111 g L^-11 for malathion and methyl parathion,respectively.The biosensor also revealed satisfactory stability,operational repeatability and good reproducibility.The average recovery within 94-106%for detection of OPs in real water and vegetable samples indicated that the AChE biosensor had excellent potential for practical application.The research results showed that the two AChE biosensors exhibited satisfactor y electrochemical performance for detection of OPs in this paper.And the AChE biosensors were fast,simple and low cost method for quantitative detection of organophosphor us pesticides.