Development of a monoclonal antibody-based immunochromatographic strip for cephalexin

An anti-cephalexin (CEX) monoclonal antibody was prepared by the immunogen of CEX-keyhole limpet hemocyanin connected by disuccinimidyl suberate, which was used for the establishment of a rapid immunochromatographic test strip. With this semi-quantitative detection method, a low limit of deduction of 10 ng mL−1 was obtained with the naked eyes and 1.3 ± 0.1 ng mL−1 by a strip reader in unprocessed milk within 5 min, which was much lower than the European Union Maximum Residue Limit of 100 µg kg−1 in milk. The recovery in the range of 87–120% was measured in another milk sample. In conclusion, this method with high sensitivity and satisfactory recovery shows significant potential for CEX residue detection in milk.