Establishment of a monoclonal antibody-based indirect enzyme-linked immunosorbent assay for the detection of trimethoprim residues in milk, honey, and fish samples

A specific monoclonal antibody (mAb) against trimethoprim (TMP) was produced and a mAb-based indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) was established to detect TMP residues in milk, honey, and fish samples. The working range of ic-ELISA and IC₅₀ was 1.83–9.36 and 4.14 µg L⁻¹. The average recoveries of TMP from TMP-spiked milk, honey, and fish sample were 103.5–118.0%, 100.3–107.1%, and 91.5–108.1%, respectively. The results revealed that our developed mAb-based ic-ELISA can be effectively applied to detect TMP residues in these food products.