Comparison between Direct Competitive ELISA and LC-MS/MS Method for Detecting Sarafloxacin Residue in Poultry

Two different analytical methods for the detection of Sarafloxacin (SAR) residue in poultry have been developed, and the comparison was also performed. For this purpose, anti-SAR monoclonal antibody (mAb) was produced through cell fusion technology and SAR-HRP tracer was synthesized using EDC method. Based on the characteristics of mAbs and square matrix titration, a direct competitive ELISA (dcELISA) method was established. The working range in assay buffer was from 0.004 to 18 ng/mL, with LOD and IC50 value of 0.002 ng/mL and 0.32 ng/mL, respectively. This assay showed negligible cross-reactivity ( < 0.05%) to other compounds tested, showing highly specific. When applied in authentic poultry samples, no significant differences between the dcELISA and the confirmatory LC-MS/MS were observed. The correlation coefficient (R2) values were 0.9876 and 0.995 in chicken, 0.9959 and 0.9841 in duck, 0.9822 and 0.9952 in geese, for dcELISA and LC-MS/MS, respectively. The results suggest it was an advantage through coupling of dcELISA as screening method and LC-MS/MS as confirmatory method for detecting SAR residue in poultry. KeywordsDirect competitive ELISA; Monoclonal antibody; Liquid chromatography tandem mass spectrometry; Sarafloxacin; Poultry