A Rapid and Green Liquid Chromatography–Tandem Mass Spectrometry Method for Monitoring Antibiotic Residues in Bear Bile Powder

A rapid and environmentally friendly analytical method was developed and validated for the simultaneous quantification of four antibiotic residues (enrofloxacin, ofloxacin, sulfamethizole, and trimethoprim) in bear bile powder. The optimized procedure features a simplified sample preparation with minimal solvent consumption and a fast chromatographic separation. Method validation confirmed excellent performance in specificity, linearity, precision, accuracy, and stability. Furthermore, the method’s greenness and practicality were quantitatively superior to a conventional approach, as evidenced by higher scores in sustainability assessments. Application to market samples revealed a notable disparity: Antibiotic residues were frequently detected in bear bile powder, while none were found in biotransformed bear bile powder. These findings furnish a reliable analytical tool for quality control and highlight biotransformed bear bile powder as a safer alternative, underscoring the impact of production practices on product safety.