Development of analytical methods for some penicillins in bovine milk by ion-paired chromatography and confirmation by thermospray mass spectrometry.
Analytical methods for the determination of cloxacillin, ampicillin/hetacillin, and amoxicillin in bovine milk were developed. The methods involved ultrafiltration of milk diluted with methanol, acetonitrile, and water on a 10,000-dalton cut-off filter. Separation of penicillins from other milk components was accomplished by ion-paired chromatography using a microbore column. The penicillins were detected using ultraviolet photodiode array (UV-PDA) detection and confirmed by thermospray liquid chromatography-mass spectrometry (LC-MS). The thermospray spectra of these compounds exhibited [M + H]+ and [M + Na]+ ions along with several fragment ions. The limits of detection for these antibiotics were estimated to be 50 to 100 ppb for LC with UV-PDA detection and 100-200 ppb for thermospray LC-MS detection.
Analytical and Chemical Sciences, Research Triangle Institute, Research Triangle Park, NC 27709.
R D
RD
Voyksner
K L
KL
Tyczkowska
A L
AL
Aronson
D000818:Animals; D002417:Cattle; D002853:Chromatography, Liquid; D007202:Indicators and Reagents; D013058:Mass Spectrometry; D008892:Milk / Q000032:analysis*; D010406:Penicillins / Q000032:analysis*; D013056:Spectrophotometry, Ultraviolet; D014462:Ultrafiltration
D007202:Indicators and Reagents; D010406:Penicillins