ASE-UHPLC-MS/MS Determination of Residual Amounts of Sulfonamides and Their Metabolites in Livestock Manure During Its Composting Course

The sample of composted livestock manure was treated with ASE and the extract obtained was purified by passing through Oasis HLB-SPE column. The purified extract was then separated by HPLC using. Waters Acquity BEH C₁₈ chromatographic column as stationary phase, and mixtures of 0.1% (φ) formic acid-methanol solution and 0.1% (φ) formic acid-H₂O solution with various ratios as mobile phase in gradient elution. ESI⁺ and multi-reactions monitoring were adopted in MS/MS. Linear relationships between values of peak area and mass concentration of the sulfonamides and their metabolites were kept in definite ranges. Detection limits (3S/N) found were ranged from 0.5 to 5.0 μg·L^-1. On the base of blank sample, test for recovery was made by standard addition method, values of recovery found were in the range of 67.3%-105%, with RSD's (n=6) in the range of 4.5%-15%.