Determination of quinolones in bovine kidney using hollow-fiber supported liquid membrane extraction prior to liquid chromatography tandem mass spectrometry

Abstract

Focus of this study was on the development of one of the faster, simpler, cost effective and environmentally friendly sample pre-treatment techniques which employs a supported liquid membrane, in this case a Hollow-fiber supported liquid membrane (HF-SLM) for determination of seven (7) quinolone antibiotics (enrofloxacin, ciprofloxacin, danofloxacin, difloxacin, norfloxacin, nalidixic acid and sarafloxacin) in bovine kidney samples followed by LC-MS/MS analysis. The key parameters of the method were optimized and the method was validated following the 2002/657 EC guidelines. The optimum HF-SLM conditions were therefore; NaH2PO4 as a donor phase at pH 7, 0.1% formic acid at pH 3 as acceptor phase. Triethylamine was the optimized liquid membrane and the stirring time was optimized at 1 hour. Separation of the 7 quinolones including 3 internal standards (enrofloxacin-d5, norfloxacin-d5 and difloxacin-d3) was carried out on a Phenomenex Kinetex 2.6 μm XB-C18, 100 mm x 4.6 mm, 100Å column. Validation parameters such as Correlation coefficients (r2) ranging from 0.9714-0.9975 were obtained, while limit of detection (LOD) ranged between 3-39 ug kg-1 and limit of quantification (LOQ) ranged between 10-130 ug kg-1. The obtained limits at which it can be concluded with an error probability of α = 95% that a sample is non-compliant (CCα) ranged from 28 – 422 ug kg-1 while CCβ; the smallest content of the substance that may be detected, identified or quantified in a sample with an error probability of β = 95%, ranged from 29 – 454 ug kg-1. The method was found to be reproducible with CVs ≤ 23 %. The tested samples from Botswana local abattoirs showed no presence of quinolone antibiotics when the method was applied to real bovine kidney samples. Hollow-fiber supported liquid membrane can therefore be used for extraction of biological samples since it is a “greener technique” which uses less solvent which are less harmful to the environment when disposed as compared to dispersive Solid Phase Extraction (dSPE).