| Abstract: | Four ELISA formats, antigen-coated indirect, antigen-coated direct, antibody-coated, and the secondary antibody-coated, were developed using monoclonal antibody to determine cephalexin. Results showed that the secondary antibody-coated method of ELISA had a better performance in the establishment of standard curves. The optimized secondary antibody-coated ELISA was used to determine cephalexin spiked in pig muscle, pig kidney, pig liver, chicken muscle, chicken liver, and cow's milk. The limits of detection were 0.09 ng/g, 0.15 ng/g, 0.26 ng/g, 0.13 ng/g, 0.19 ng/g, and 0.08 ng/mL in pig muscle, pig kidney, pig liver, chicken muscle chicken liver, and cow's milk, respectively. A mean recovery of 77.2–128.5% and coefficient of variation of 2.6–14.7% were obtained. The results given by the ELISA method were in agreement with those of the LC-MS/MS method, which confirmed the potential of the ELISA method for the monitoring of cephalexin in milk and animal tissues. |
