Development of an enzyme-linked immunosorbent assay for the detection of gentamycin residues in animal-derived foods

Abstract

An enzyme-linked immunosorbent assay (ELISA) was developed using a polyclonal antibody with high affinity and specificity for detecting gentamycin in animal-derived foods. The half-maximum inhibition concentration (IC50) and limit of detection (LOD, calculated as IC15) of the ELISA for gentamycin in phosphate buffer were 0.3 and 0.03 ng/ml, respectively. The assay showed low cross-reactivity with other aminoglycoside antibiotics except sisomycin (52.5%), which indicated that the assay had high specificity. The trichloroacetic acid solution was selected as extraction buffer for eight animal-derived foods to effectively eliminate the matrix effect and extract gentamycin. The recoveries for gentamycin from eight fortified food samples, at three concentrations of 8, 20, and 50 μg/kg, were ranged from 69% to 118% and the coefficients of variation were less than 12%. The LODs of this assay for gentamycin in eight chosen animal-derived foods were 3 μg/kg. The whole detecting process could be finished within 1.5 h. The ELISA allows for a rapid, sensitive, specific, accurate, and low-cost determination of gentamycin residues in animal-derived foods.