Dispersive liquid-liquid microextraction of parabens

Dispersive liquid-liquid microextraction is suggested for sampling and preconcentration of parabens. Effects of extraction solvent type, extraction and disperser solvent volume, extraction time and the ionic strength of the solution on the extraction efficiency were investigated. Chlorobenzene containing n-nonadecane as an internal standard was used as an extracting solvent, and acetone was used as a disperser solvent. The calibration graphs were linear up to 10 mg mL(-1), the correlation coefficients were 0.997-0.999, the enrichment factors varied from 20 for methylparaben to 190 for butylparaben, and the detection limits were 210, 23, 15 and 8 mu g L-1 for methylparaben, ethylparaben, propylparaben and butylparaben, respectively. The repeatability of the results was acceptable (relative standard deviations up to 11.2%). A possibility to apply the proposed method for paraben determination in water samples was demonstrated.