Stability of sulfonamides, nitrofurans, and chloramphenicol residues in preserved raw milk samples measured by liquid chromatography.

摘要: A stability study was made of 10 antimicrobials: 6 sulfonamides, 3 nitrofurans, and chloramphenicol residues in raw milk samples preserved with 0.1 % potassium dichromate (K2Cr2O7) 0.05% mercuric bichloride (HgCl2) during cold storage for 7 days. Preserved fortified 50 ppb each antimicrobial were analyzed by liquid chromatography (modified AOAC Method 993.32). Drugs extracted chloroform-acetone after solvent evaporation dissolved aqueous sodium acetate buffer solution (0.02M, pH 4.8), fat removed hexane. Sulfonamides detected at 275 nm (UV) using a gradient system solution-acetonitrile starting 95 + 5 (v/v) finishing 80 20 (v/v). Nitrofurans 375 isocratically (80 20, v/v). Residues measured through recovery data. Sulfamethoxazole, sulfachloropyridazine, nitrofurazone, furazolidone, furaltadone remained stable the presence either preservative Sulfamethazine not affected K2Cr2O7, but had significant losses (p <0.05) when HgCl2 used: 26.2 13.4%, respectively. Average recoveries sulfamonomethoxine, sulfamerazine, sulfathiazole significantly decreased Day 7, 17.1, 17.2, 23.2% 23.3, 20.7, 48.0% HgCl2, During days all antimicrobials tested, except sulfathiazole, K2Cr2O7 or HgCl2.