Development of LC-MS/MS methodology for the detection/determination and confirmation of chloramphenicol, chloramphenicol 3-O-β-d-glucuronide, florfenicol, florfenicol amine and thiamphenicol residues in bovine, equine and porcine liver.

A method for the detection and confirmation of organic solvent extractable residues of the neutral, acidic, and basic analytes of the amphenicol class veterinary drugs and selected metabolites was developed and validated. Using a modified QuEChERS extraction with SPE cleanup and LC-MS/MS analysis, limits of detection and confirmation for the different analytes in bovine, equine, and porcine liver ranged from 0.1ng/g for chloramphenicol to 1ng/g for florfenicol amine.

Development and validation of determinative and confirmatory LC-MS/MS methodologies for total florfenicol and tulathromycin residues in bovine, equine and porcine kidney, liver and muscle tissues.

Separate methods for the quantitation and confirmation of regulatory relevant residue concentrations of total florfenicol and tulathromycin residues in multiple tissue matrices were developed and validated. Total florfenicol residues, determined and expressed as florfenicol amine (FFA) equivalents, were quantified and confirmed over a concentration range of 100-4000ng/g, with an LOD of 33ng/g, while total tulathromyicn residues, determined as CP-60,300 and expressed as tulathromycin equivalents, were quantified and confirmed over a concentration range of 500-10,000ng/g, with an LOD of 300ng/g. A 2 or 1h acid digestion for the FFA and tulathromycin methods, respectively, followed by extraction, cleanup, and concentration using mixed-mode strong cation-exchange SPE cartridges was used.

Alternative methodology for the analysis of progesterone, testosterone, and epi-testosterone in bovine liver and veal muscle.

Research has shown that traditional solvent extraction procedures used for the analysis of endogenous steroids often give inconsistent recoveries and results. However, a single-laboratory validation of a liquid chromatography/tandem mass specrometry method using 2 product ions per transition for progesterone, testosterone, and epi-testosterone in bovine liver and veal muscle showed accuracy and precision to within 23% at concentrations ranging from 0.5 to 2.