Liquid chromatographic determination of multiple sulfonamides, nitrofurans, and chloramphenicol residues in pasteurized milk.
A rapid and selective liquid chromatographic method was developed to detect 6 sulfonamides, 3 nitrofurans, and chloramphenicol residues in pasteurized milk. The 10 drugs were extracted with chloroform-acetone and the organic phase was evaporated; the residues were dissolved in an aqueous sodium acetate buffer solution 0.02M (pH = 4.8), and the fat was removed by washing with hexane. The aqueous layer was collected, filtered, and injected. The 6 sulfonamides and chloramphenicol were detected at 275 nm ultraviolet (UV) using a gradient system starting with sodium acetate buffer solution-acetonitrile (95 + 5) and finishing with sodium acetate buffer solution-acetonitrile (80 + 20). Nitrofurans were detected at 375 nm (UV) isocratically with sodium acetate buffer solution-acetonitrile (80 + 20). For 50 ppb fortified milk, the average recoveries were (sulfathiazole) 65.52%; (sulfamerazine) 75.36%; (sulfamethazine) 93.94%; (sulfachlorpyridazine) 75.94%; (sulfamethoxazole) 85.18%; (sulfamonomethoxine) 83.45%; (chloramphenicol) 104.17%; (nitrofurazone) 91.81%; (furazolidone) 100.76%; and (furaltadone) 72.38%. Method detection limits ranged from 4 ppb (nitrofurazone) to 16 ppb (sulfamethazine). Some matrix interferences (3-7 ppb) were observed only with sulfonamides.
Perez
Norma
N
Universidad Autónoma Metropolitana, Departamento de Producción Agrícola y Animal, México, Distrito Federal. normaaperez@hotmail.com
Gutierrez
Rey
R
Noa
Mario
M
Diaz
Gilberto
G
Luna
Hector
H
Escobar
Irma
I
Munive
Zenaida
Z
D000818:Animals; D000900:Anti-Bacterial Agents / Q000032:analysis*; D000890:Anti-Infective Agents / Q000032:analysis*; D002417:Cattle; D002701:Chloramphenicol / Q000032:analysis*; D002853:Chromatography, Liquid; D004350:Drug Residues / Q000032:analysis*; D005260:Female; D007202:Indicators and Reagents; D008800:Mexico; D008892:Milk / Q000737:chemistry*; D009581:Nitrofurans / Q000032:analysis*; D012015:Reference Standards; D012996:Solutions; D013449:Sulfonamides / Q000032:analysis*
D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents; D007202:Indicators and Reagents; D009581:Nitrofurans; D012996:Solutions; D013449:Sulfonamides; D002701:Chloramphenicol