LAUSR

ABSTRACT A sensitive monoclonal antibody, 1H2, was generated in this study that simultaneously recognizes avermectin and ivermectin. An indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) was developed, with 50% inhibitory concentrations of 0.491 ng/mL for avermectin and 0.770 ng/mL for ivermectin. A lateral-flow immunochromatographic assay (ICA) strip was also developed based on this monoclonal antibody for the semiquantitative and quantitative detection of avermectin and ivermectin. The semiquantitative (with the naked eye) analysis had visual limits of detection of 10 ng/mL for avermectin and 25 ng/mL for ivermectin, with cut-off values of 25 and 50 ng/mL, respectively. Using a strip scan reader, the quantitative results had calculated limits of detection of 1.3 ng/mL for avermectin and 2.9 ng/mL for ivermectin. In an analysis of raw milk samples, the recovery rates for the ic-ELISA ranged from 94% to 112% and for the ICA strip from 110% to 125%. Therefore, both methods are sensitive and effective for the on-site detection and rapid screening of samples, and are suitable for various other applications.