Multicolor enzyme-linked immunosorbent sensor for sensitive detection of organophosphorus pesticides based on TMB2+-mediated etching of gold nanorods

• A multicolor enzyme-linked immunosorbent sensor was developed for the detection of OPs. • The naked eye LOD of the sensing system is 0.25 ng mL −1 . • Three OPs can be qualitative and quantitative analysis by using this multicolor enzyme-linked immunosorbent sensor. • It is a sensitive and reliable assay for the detection of OPs in complex food samples. A multicolor enzyme-linked immunosorbent sensor was constructed to detect organophosphates pesticides (OPs) on base of TMB 2+ -mediated AuNRs etching. As the etching progresses, a rainbow-like color responses was generated. The naked eye limit of detection (LOD) of the sensing system is 0.25 ng mL −1 . In particular, the longitudinal localized surface plasmon resonances (LSPR) peak shift of AuNRs is linearly correlated with the logarithm of OPs concentration in range of 10 4 to 5 × 10 6 pg mL −1 for parathion-methyl and fenitrothion, 5 × 10 4 to 10 7 pg mL −1 for fenthion, respectively. Compared with reported methods, this sensor displayed satisfactory linear ranges and detection limits. Average recoveries of this method ranged from 73.28% to 98.08% and relative standard deviations (RSDs) were below 8.0% as for food samples analysis without complicated pretreatments. Remarkably, the developed multicolor enzyme-linked immunosorbent sensor is capable of providing accurate and reliable assay for OPs in complex food samples.