Method for determination of streptomycin and streptidine as markers for streptomycin industrial dregs monitoring in pig and poultry compound feeds

Antibiotic industrial dregs, generated from the production of antibiotics by fermentation, are banned in China as animal feed additives. Official monitoring programs require the analysis of feeds for possible illegal use of the dregs. A rapid and sensitive method was developed for the simultaneous determination of streptomycin and streptidine as markers for streptomycin industrial dregs in pig and poultry compound feeds. After extraction with 20% aqueous trichloroacetic acid and pH adjustment, sample cleanup was performed by weak cation-exchange solid-phase extraction. UPLC-ESI-MS/MS was carried out using a hydrophilic interaction chromatography(HILIC)column to achieve separation. Quantification required matrix-matched calibrations in a linear range of 50-1000 μg kg−1; the calibration curves were linear in this range with coefficients of determination of 0.991 and 0.994 for streptomycin and streptidine, respectively. The method validity parameters-LODs (20 μg kg−1) and LOQs (50 μg kg−1), recoveries (71-78% and 75-84%, respectively), and relative reproducibility (5.4-9.6%)-satisfy the requirements of routine analysis.