An ionic liquid-based hollow fibre liquid-phase microextraction method for the determination of four anti-epileptic drugs in human blood samples by gas chromatography–mass spectrometry using chemometrics methodology

The occurrence of pharmaceuticals in the environment has led to a growing concern in recent years [1], particularly with regard to their potential risks to the aquatic environment [2]. In this study, a novel method called ionic liquid mediated hollow fiber liquid-phase microextraction (IL-HF-LPME), coupled with gas chromatography–mass spectrometry (GC-MS) has been proposed for the preconcentration and determination of four anti-epileptic drugs (sodium valproate, pregabalin, levetiracetam and phenobarbital) in hospital waste water and blood samples. Several procedures, most of them spectrophotometric, are available for the determination of these drugs [3]. However, by gas chromatography it is possible to process large numbers of samples within a short time without loss of accuracy and specificity [4]. In the present work, 1-butyl- 3-methy-limidazolium hexa fluoro phosphate (ionic liquid) was placed in the porous-walled polypropylene hollow fiber as the acceptor phase, and 1-dodecanol was used as the supported liquid membrane phase that accomplished extraction. Several important parameters influencing the extraction efficiency were investigated in detail. Parameters affecting extraction efficiency have been investigated and optimized for the proposed method using Taguchi experimental design and response surface methodology respectively. Under the optimum conditions, good linearities were observed for all target drugs in the range of 0.005–8.00 μg.mL-1 with the correlation coefficients ranging from 0.985 to 0.989. Intra (n=6) and inter-day (n=5) precisions of the method were satisfactory with relative standard deviations less than 4.9% (at three concentrations of 0.01, 0.1 and 1 μg.mL-1 of each analyte). Recoveries of four drugs in spiked blood samples (0.1 μg.mL-1) were between 96.1 and 105.2% and the enrichment factors were 1500. The proposed method allowed the simple, rapid and sensitive determination of anti-epileptic drugs in blood samples with an extraction time of just 10 min.