development of homogeneous liquid-liquid microextraction via flotation assistance method for determination of benzene, toluene, xylene and styrene in water samples

this study propose a new analytical protocol for the determination of benzene, xylene, toluene and styrene in water samples using homogeneous liquid-liquid microextraction via flotation assistance (hllme-fa) technique followed by gas chromatography-mass spectrometry (gc-ms). in this research, a special extraction cell was designed to facilitate collection of the low-density solvent extraction. no centrifugation was required in this procedure. the water sample solution was added into the extraction cell which contained an appropriate mixture of extraction and homogeneous solvents. by using air flotation, the organic solvent was collected at the conical part of the designed cell. the effects of different variables on the efficiency of the extraction were studied simultaneously using experimental design. response surface methodology was applied to investigation the optimum conditions of each variable. using optimized variables in the extraction process, for all target analytes, the detection limits, the precisions and the linearity of the method were found in the range of 0.8-8.2 ng ml-1, 3.09-7.96% (rsd, n=4) and 1-100 ng ml-1, respectively. the headspace method was used for the accuracy of comparison. the performance of the method was evaluated for extraction and determination of analytes in water samples and satisfactory results were obtained (rsd ≤10.06 %).