ABSTRACT
A rapid and highly sensitive ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) assay was developed for quantification of 7 antibiotics in low sample volumes (50⯵L): amoxicillin, azithromycin, cefotaxime, ciprofloxacin, meropenem, metronidazole and piperacillin, for both routine monitoring and pharmacokinetic studies. After protein precipitation by acetonitrile, the antibiotics were separated on an Acquity UPLC HSS T3 column (run time, 4â¯min). The mobile phase consisted of a mixture of (A) ammonium acetate (pH 2.4; 5â¯mM) and (B) acetonitrile acidified with 0.1% formic acid, delivered at 500⯵l/min in a gradient elution mode. Total time run was 2.75â¯min. Ions were detected in the turbo-ion-spray-positive and multiple-reaction-monitoring modes. The assay was accurate and reproductible for the quantification of the seven antibiotics in serum samples over large concentration ranges.