Indirect Competitive Enzyme-Linked Immunosorbent Assay for Detection of Tylosin in Milk and Water Samples

A specific polyclonal antibody was prepared based on a new hapten with stable structure. Based on this, an indirect competitive enzyme-linked immunosorbent assay (icELISA) was established for determination of tylosin residues in food and environmental samples. The experimental conditions were optimized as follows: the coating antigen and antibody were respectively diluted by 6000 times and 2000 times, and the competitive reaction time was 40 min. Under the optimized conditions, the method showed a detection limit of 0.07 ng mL −1 , an IC 50 of 1.39 ng mL −1 and a linear range of 0.17–11.0 ng mL −1 . The recoveries of spiked raw milk and water samples were ranged from 78.4% to 105.6%, with the RSDs of less than 15%. Good correlation between icELISA and HPLC method was obtained for spiked samples ( R 2 = 0.97). This method was suitable for the determination of tylosin residues in milk and water samples.