PRECONCENTRATION AND DETERMINATION OF SHORT CHAIN MERCAPTANS IN THE PRODUCED WATER BY DISPERSIVE LIQUID-LIQUID MICROEXTRACTION AND GAS CHROMATOGRAPHY

This paper describes the preconcentration of short chain n-alkyl C1-C6 mercaptans in the produced water using the dispersive liquid-liquid microextraction. In the present experiments, 0.8 mL dispersive solvent (acetonitrile) containing 10.0 μL extraction solvent (carbon tetrachloride) was rapidly injected into the samples and followed by centrifuging and direct injection into the gas chromatograph equipped with flame ionization detector. According to the results, dispersive liquid-liquid microextraction gas chromatography flame-ionization detector was successfully used for determination of short chain n-alkyl C1-C6 mercaptans. The parameters affecting the extraction efficiency were evaluated and optimized. Under the optimum conditions, the figures of merits for six short chain n-alkyl C1-C6 mercaptans were determined to be 4.0-100.0 ng/L (n = 6, RSD = 6.8%), 6.0-80.0 ng/L (n = 6, RSD = 11.0%), 2.0-90.0 ng/L (n = 6, RSD = 2.6%), 5.0-120.0 ng/L (n = 6, RSD = 4.4%), 3.0-80.0 ng/L (n = 6, RSD = 9.2%) and 2.0-110.0 ng/L (n = 6, RSD = 6.5%), respectively.