Determination of Organic Sulfur Contaminants Using Hollow Fibre-protected Liquid-phase Micro-extraction Coupled with Gas Chromatography

A simple and solvent-minimized sample preparation technique based on hollow fibre-protected liquid-phase micro-extraction has been developed for extraction of fifteen organic sulphur compounds from aqueous samples. The analysis of the extracted them was performed by gas chromatography equipped with mass spectrometry and/or flame photometric detectors. ۳.۳ µL of organic solvent located in the lumen of hollow fibre was used to extract OSCs from an ۸ mL of aqueous sample. Several parameters influencing extraction efficiency such as salt concentration, stirring speed, temperature, sample volume, organic phase volume and extraction time were studied and optimized using super-modified simplex method. Under optimized conditions, including extraction solvent (toluene) extraction time (۱۵ min ), salt addition (۴ % w/v), stirring rate (۱۲۰۰ rpm), sample volume (۸ ml SV), organic solvent volume (۳.۳ µl) and extraction temperature (۳۵oC), the limits of detection varied from ۰.۱ to ۸.۷ µg/L and ۰.۷ to ۹۹.۴ µg/L for GC-FPD and GC-MS, respectively. The calibration graphs were linear over three orders of magnitude for most of the studied OSCs. The relative standard deviations for inter- and intra-day analysis were in the range of ۵ to ۱۰%, and the relative recoveries of the analytes from the three different real water samples were more than ۸۳%. The results were compared with those obtained using direct single drop micro-extraction and headspace single drop micro- methods. The proposed method is reliable and can be considered useful for routine monitoring of the organic sulphur compounds in surface water samples.

کلیدواژه ها:

Hollow Fiber ، Liquid-phase micro-extraction ، Organic sulfur