title: Surveillance study of novobiocin and phenylbutazone residues in raw bovine milk using liquid chromatography-tandem mass spectrometry.
abstract: A simple method permitting the simultaneous determination of trace residues of novobiocin and phenylbutazone in raw milk samples using liquid chromatography-tandem mass spectrometry was developed. Raw milk samples were mixed with acetonitrile to facilitate the concurrent precipitation of milk proteins and extraction of both veterinary drugs. Without additional clean-up or concentration of the resulting extract, the analytes could be quantified at concentrations as low as 0.0025 and 0.001 microg ml(-1) for phenylbutazone and novobiocin, respectively. The analysis of a series of fortified raw milk samples at analyte concentrations ranging from 0.005 to 0.1 microg ml(-1) and from 0.01 to 0.2 microg ml(-1) for phenylbutazone and novobiocin, respectively, yielded average recoveries ranging from 89.2% to 104.3% with standard deviations below 7%. The analytical method was applied to the analysis of raw milk samples collected from transport trucks upon delivery at dairy-processing plants throughout Alberta, Canada. Novobiocin was detected in 13 of 1072 samples tested at concentrations ranging from 0.001 to 0.007 microg ml(-1). Phenylbutazone was not detected in any of the samples tested.
authors.affiliation: Alberta Agriculture & Rural Development, Food Safety & Animal Health Division, Edmonton, AB, Canada. tom.thompson@gov.ab.ca
authors.forename: T S
authors.initials: TS
authors.lastname: Thompson
authors.forename: D K
authors.initials: DK
authors.lastname: Noot
authors.forename: J D
authors.initials: JD
authors.lastname: Kendall
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000032:analysis* / Q000737:chemistry; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000032:analysis* / Q000737:chemistry; D002170:Canada; D002851:Chromatography, High Pressure Liquid; D004350:Drug Residues / Q000032:analysis* / Q000737:chemistry / Q000592:standards; D005506:Food Contamination / Q000517:prevention & control; D005513:Food Inspection / Q000379:methods* / Q000592:standards; D057230:Limit of Detection; D008892:Milk / Q000737:chemistry*; D009675:Novobiocin / Q000032:analysis* / Q000737:chemistry; D056687:Off-Label Use / Q000662:veterinary; D010653:Phenylbutazone / Q000032:analysis* / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization; D053719:Tandem Mass Spectrometry; D014481:United States; D019155:Veterinary Drugs / Q000032:analysis / Q000737:chemistry
chemical_list: D000900:Anti-Bacterial Agents; D000894:Anti-Inflammatory Agents, Non-Steroidal; D019155:Veterinary Drugs; D009675:Novobiocin; D010653:Phenylbutazone