A broad-spectrum antibody-based lateral flow immunoassay for detection of carbofuran and 3-hydroxy-carbofuran.

Simultaneous detection of carbofuran (CBF) and 3-hydroxy carbofuran (3-OH-CBF) in fruits and vegetables is important due to their high toxicity and widespread use in pest control. However, most lateral flow immunoassay (LFA) approaches only detection CBF. To overcome this limitation, two haptens, 6-((2,2-dimethyl-2,3-dihydrobenzofuran-7-yl)oxy)hexanoic acid and 6-((((2,2-dimethyl-2,3-dihydroben zofuran-7-yl)oxy)carbonyl)amino)hexanoic acid, named H1 and H2, were designed for broad-spectrum antibody detection of CBF and 3-OH-CBF. The highly specific monoclonal antibody (mAb) 3F4 based on hapten H1 only recognized CBF, while broad-spectrum mAbs 1D3, 6B7 and 6E8 based on hapten H2 recognized both compounds. The carbon bond to the hydroxyl group of 3-OH-CBF adopts a 28.55° angle relative to the same carbon bond of CBF, explaining the specificity of the H1-based mAb against CBF. After optimizing the antigen-antibody combination, a sensitive colloidal gold-LFA (CG-LFA) strip was constructed based on mAb 1D3 and H2-BSA for CBF and 3-OH-CBF detection following simple sample pretreatment. The established LFA had a limit of detection of 0.49-6.63 ng/mL, and adequate recoveries (69.3-105.7 %) for CBF and 3-OH-CBF in 26 fruit and vegetable samples.