Analysis of penicillin G in milk by liquid chromatography.
A liquid chromatographic (LC) method that was previously developed for penicillin G residues in animal tissues has been adapted to milk and milk products. After protein precipitation with sodium tungstate, samples are applied to a C18 solid-phase extraction cartridge, from which penicillin is eluted, derivatized with 1,2,4-triazole-mercuric chloride solution, and analyzed by isocratic liquid chromatography (LC) on a C18 column with UV detection at 325 nm. Quantitation is done with reference to penicillin V as an internal standard. Penicillin G recoveries were determined to be > 70% on standards fortified at 3-60 ppb. Accuracy approached 100% using the penicillin V internal standard. The detection limit for penicillin G residues was 3 ppb in fluid milk. Samples may be confirmed by thermospray/LC at concentrations approaching the detection limit of the UV method.
Agriculture Canada, Food Production and Inspection Branch, Saskatoon, SK.
J O
JO
Boison
L J
LJ
Keng
J D
JD
MacNeil
D000818:Animals; D002853:Chromatography, Liquid / Q000379:methods* / Q000706:statistics & numerical data; D008892:Milk / Q000737:chemistry*; D010400:Penicillin G / Q000032:analysis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D010400:Penicillin G