Development of a rapid and sensitive enzyme-linked immunosorbent assay to detect clonidine residues in swine urine samples

Abstract

Clonidine (CLD) may be illegally used on animals because it can play the role of growth promoters. For the first time, a rapid direct competitive enzyme-linked immunosorbent assay (ELISA) was established based on polyclonal antibodies to detect CLD. The antibody showed high sensitivity, with the limit of detection (LOD) and IC50 being 0.01 and 0.056 µg/L, respectively. The specificity of the assay was evaluated by the measurement of cross-reactivity (CR) of the antibody with related compounds. Recovery rates ranged from 88% to 94%, and the coefficient of variation was below 11% for intra- and inter-assays. Highly consistent results were obtained for the urine samples by ELISA and UPLC-MS/MS method. It indicates good parallelism, accuracy and precision of the assay. The prototype kit could be advantageously used for the screening of large groups of urine samples, and has reliability even in routine application for the control of the illegal use of the drug.