Chemiluminescent Detection of Gatifloxacin Residue in Milk

An indirect competitive chemiluminescent enzyme-linked immunosorbent assay (CL-ELISA) for detection of gatifloxacin residue in milk was developed in this study. Compared with conventional colorimetric ELISA using the same antibody, the developed CL immunoassay shows a significant improvement in sensitivity and detectability with an IC50 of 0.4 ng mL−1 and a detection limit of 0.001 ng mL−1 and thus is suitable to be used as a highly sensitive screening method to detect and regulate illegal use of gatifloxacin in food and food products. The test kit was applied to detect milk samples spiked by gatifloxacin, and satisfactory results were obtained.