title: Development of a MAb-based immunoassay for the simultaneous determination of O,O-diethyl and O,O-dimethyl organophosphorus pesticides in vegetable and fruit samples pretreated with QuEChERS.
abstract: To develop a broad-specificity immunoassay for organophosphorus pesticides (OPs), a broad-specificity monoclonal antibody (MAb) for OPs against a generic hapten, O,O-diethyl O-(3-carboxyphenyl) phosphorothioate with the carboxy group in the meta position of the benzene ring, was produced. Eight haptens were prepared and covalently attached to ovalbumin (OVA) for use as coating antigens, and the optimum coating antigen was selected. Then, a sensitive and broadly class selective competitive indirect enzyme-linked immunosorbent assay (ciELISA) based on the MAb and the optimum coating antigen (hapten H-OVA, possessing an O,O-dimethyl generic structure and linked through a linear spacer arm) was developed and optimized. The MAb developed in this study showed quite different cross-reactivity and selectivity compared to previously produced anti-OPs broad-specificity MAbs. Specifically, the MAb showed high and uniform sensitivity to seven O,O-diethyl OPs and six O,O-dimethyl OPs. With the optimum ciELISA, the IC50 values of the 13 OPs were determined as 23.1∼151.2 ng mL(-1). The average IC50 and coefficient of variation (CV) for the IC50 values of the 13 OPs were 74.6 ng mL(-1) and 33.9%, respectively. For the recovery study, a QuEChERS approach based on dispersive solid-phase extraction (d-SPE) was implemented to decrease the matrix effects of vegetable and fruit samples. The recoveries of six representative OPs from the spiked samples ranged from 89.4 to 135.5%; the CV ranged from 3.5 to 15.7%. The ciELISA was also applied to real samples, followed by confirmation with gas chromatography-tandem mass spectrometry (GC-MS/MS) analysis. The results demonstrated that the ciELISA is suitable for monitoring OP contamination in vegetable and fruit samples.
authors.affiliation: Department of Microbiology, College of Life Science, Key Laboratory for Agriculture Microbiology, Shandong Agricultural University, Tanan, 271018, China.
authors.forename: Fengchun
authors.initials: F
authors.lastname: Zhao
authors.affiliation: Department of Microbiology, College of Life Science, Key Laboratory for Agriculture Microbiology, Shandong Agricultural University, Tanan, 271018, China.
authors.forename: Chunyan
authors.initials: C
authors.lastname: Hu
authors.affiliation: Department of Microbiology, College of Life Science, Key Laboratory for Agriculture Microbiology, Shandong Agricultural University, Tanan, 271018, China.
authors.forename: Huimin
authors.initials: H
authors.lastname: Wang
authors.affiliation: Department of Microbiology, College of Life Science, Key Laboratory for Agriculture Microbiology, Shandong Agricultural University, Tanan, 271018, China.
authors.forename: Longyu
authors.initials: L
authors.lastname: Zhao
authors.affiliation: Department of Microbiology, College of Life Science, Key Laboratory for Agriculture Microbiology, Shandong Agricultural University, Tanan, 271018, China. zhyouyang@sdau.edu.cn.
authors.forename: Zhengyou
authors.initials: Z
authors.lastname: Yang
mesh_terms: D000911:Antibodies, Monoclonal / Q000032:analysis; D005506:Food Contamination / Q000032:analysis; D005638:Fruit / Q000737:chemistry*; D007118:Immunoassay / Q000379:methods*; D015394:Molecular Structure; D009943:Organophosphorus Compounds / Q000737:chemistry* / Q000302:isolation & purification; D010575:Pesticides / Q000737:chemistry* / Q000302:isolation & purification; D052616:Solid Phase Extraction; D014675:Vegetables / Q000737:chemistry*
chemical_list: D000911:Antibodies, Monoclonal; D009943:Organophosphorus Compounds; D010575:Pesticides
keywords: Broad specificity; Organophosphorus pesticides; QuEChERS; ciELISA; d-SPE