Determination of trimethoprim in bovine serum by high-performance liquid chromatography with confirmation by thermospray liquid chromatography-mass spectrometry.
A high-performance liquid chromatographic (HPLC) method with a detection limit of 5 ng/ml was developed for the analysis of trimethoprim in bovine serum. Trimethoprim and the internal standard, ormetoprim, under alkaline conditions, were first extracted into dichloromethane and then back-extracted into dilute sulphuric acid (0.15 M) and cleaned-up on a C18 cartridge. Trimethoprim was quantified on a C18 column using a triethylammonium acetate-acetonitrile-methanol (16:3:1, v/v/v) mobile phase at a flow-rate of 1.5 ml/min, with ultraviolet detection at 225 nm. This method was used to verify the accuracy of test responses obtained with the Brilliant Black Reduction test, a rapid screening method, for trimethoprim levels in the serum of steers treated with Trivetrin. Confirmation of the presence of trimethoprim in the sample extract was obtained by thermospray HPLC-mass spectrometry.
Chemistry Department, University of Saskatchewan, Saskatoon, Canada.
P
P
Nachilobe
J O
JO
Boison
R M
RM
Cassidy
A C
AC
Fesser
D000818:Animals; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D002853:Chromatography, Liquid; D004338:Drug Combinations; D008297:Male; D013058:Mass Spectrometry; D012015:Reference Standards; D013056:Spectrophotometry, Ultraviolet; D013412:Sulfadimethoxine / Q000032:analysis; D013413:Sulfadoxine / Q000032:analysis; D013418:Sulfamethazine / Q000032:analysis; D014295:Trimethoprim / Q000097:blood*
D004338:Drug Combinations; D013412:Sulfadimethoxine; D013418:Sulfamethazine; D013413:Sulfadoxine; D014295:Trimethoprim