Extraction of phenolic compounds from environmental water samples using oil-in-water emulsions

A fast, sensitive and simple oil-in-water emulsion (OWE) method was developed for extraction of four phenolic pollutants in environmental water samples followed by gas chromatography and flame ionization detection. In this method, the density of a binary organic solvent (one heavier and one lighter than the sample) was balanced with the density of the sample solution. A stable emulsion was formed at room temperature under vigorous stirring using a Teflon-coated magnetic stirring bar. After addition of 10 A mu L of the heavier organic solvent and centrifugation, phase separation occurred. The influence of several important parameters on the extraction efficiency of phenolic compounds was evaluated. Under optimized experimental conditions, the calibration graphs were linear in the concentration range 0.025-20 mg L-1 with coefficients of determination more than 0.9994. The limits of detection and quantification were in the range 19.2-76.0 and 64.1-251.0 mu g L-1, respectively. Intra-day and inter-day precisions were less than 5.0 %. The procedure was used for the determination of phenolic compounds in spiked water samples with good results. Recoveries range from 96.5 to 103.0%, and relative standard deviations are < 2.5% (for n = 3).