Development Of An Electrochemical Biosensor For Multi-residue Detection Of Organophosphorus Pesticides

Organophosphorus pesticides(OPs)have been widely used in various crops,and aroused intensive concerns of the society.Detection of trace OPs has become a hotspot in this field.We developed three kinds of electrochemical sensors for quick detection of OPs based on the strong combine ability of OPs and acetylcholinesterase(AChE).These sensors have the advantages of simple preparation,high sensitivity,high precision and good stability.OPs in real vegetables and fruits were detected and the result was satisfying.Chapter 1:The characteristic and detection methods of OPs were summarized;the application of graphene in biosensor and the main research contents of this paper were also summarized.Chapter 2:Graphene-chitosan(RGO-CHI)composite was prepared and a kind of RGO-CHI-Parathion modified electrochemical biosensor was developed for the detection of 11 OPs.The results showed a good linearity of 1～1500 ng/mL and the limits of detection(LODs)were about 0.012～0.33 ng/mL.The recoveries of chlorpyrifos in apple and trichlorfon in green vegetables were form 87.2%to 110.2%.Chapter 3:One kind of RGO-CHI-methamidophos modified biosensor was developed for 11 OPs detection.The results showed a good linearity of 1～1500 ng/mL and the LODs were about 0.026～0.526 ng/mL.The recoveries of chlorpyrifos in apple and trichlorfon in green vegetables were in the range of 90.7%to 119.4%.Chapter 4:Methamidophos was covalently linked to a gold-nanoparticle(GNPs)modified electrode.The chemically modified sensor showed better repeatability than physically absorpted biosensors.The recoveries of chlorpyrifos in apple and trichlorfon in green vegetables were in the range of 81.45%to 103.82%.Besides,the total OPs concentration was also detected and showed a relative standard deviation(RSD)below 10%when total OPs concentration was between 50～1000 ng/mL.This paper developed three kinds of electrochemical biosensors for multiple OPs detection.The sensors was conveniently prepared and have the advantages of high sensitivity,high precision,and good stability.Total OPs was determinated using one of the biosensor.