Ionic liquid/ionic liquid dispersive liquid-liquid microextraction, a new sample enrichment procedure for the determination of hexabromocyclododecane diastereomers in environmental water samples

In this paper, a new ionic liquid/ionic liquid dispersive liquid-liquid microextraction (IL/IL-DLLME) procedure has been developed for the rapid enrichment and determination of three hexabromocyclododecane diastereomers (alpha-, beta- and gamma-HBCD) in environmental water samples prior to rapid resolution liquid chromatography-electrospray tandem mass spectrometry (RRLC-ESI-MS/MS). In the IL/IL-DLLME procedure, two kinds of ionic liquids (ILs), a hydrophobic IL and a hydrophilic IL, were used as an extraction solvent and a disperser solvent, respectively. Some important parameters that might affect the extraction efficiencies were optimized. Under the optimum conditions, the limits of detection could reach 0.12-0.22 mu g L-1, and the precisions were 4.1-6.7% (n = 7). The linear range was obtained over the range 1-100 mu g L-1 for the total concentration of the three HBCD diastereomers. It was satisfactory to analyze real environmental water samples with the recoveries ranging from 88.0 to 114%. All these facts indicated that the IL/IL-DLLME procedure would be a simple alternative for the rapid enrichment and analysis of pollutants in environmental water samples.