Validation and optimization of a liquid-phase microextraction method for trace analysis of BTEX in water samples

Abstract

Liquid-phase microextraction (LPME) based on solidification of a floating organic micro drop followed by gas chromatography (flame ionization detection) to pre-concentrate and determine benzene, toluene, ethylbenzene and xylenes (BTEX) in aqueous samples has been investigated. The effects of type and volume of extraction solvent, stirring rate, extraction time, temperature and ionic strength in LPME of BTEX were evaluated. The results confirm that the proposed procedure provides improved accuracy, linear range, limit of detection, limit of quantification and is very effective for analyzing the BTEX compounds in water samples. Under the optimized conditions, pre-concentration factor of 149–285 and extraction efficiency of 31–61% were obtained. Repeatability (1.59–5.83%, n = 6) and intermediate precision (2.05–7.14%, n = 15) are in an acceptable range. The relative recovery obtained for each analyte in different water samples is higher than 82.3% at three fortification levels with the relative standard deviation of less than 7.5%.