Abstract: An one-step indirect competitive ELISA system for detection of melamine residues in milk was developed based on monoclonal antibody,and the performance about the detection system such as recoveries,sensitivity,precision and specification were evaluated. The random samples after detected by ELISA had confirmed by LC-MS/MS to access its practicality. The results showed that the calibration curve of this ELISA detection system had the linear detection of 10 to 810 ng/mL,the sensitivity of 10 ng/mL, and the recoveries of 84.0% to 90.0% in milk,with the cross-reactivity within 0.1%. Therefore,the one-step ELISA established in this study is a practical method for determination of melamine residue in milk.

Key words: melamine; milk; ELISA; one-step method