Abstract: 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%.