Preconcentration and determination of bisphenol A, naphthol and dinitrophenol from environmental water samples by dispersive liquid-phase microextraction and HPLC

This paper describes a new, rapid and reliable determination method for bisphenol A, 1-naphthol, 2-naphthol and 2,4-dinitrophenol using dispersive liquid-phase microextraction prior to high-performance liquid chromatography. In this method chlorobenzene was used as the extraction solvent and acetone was used as the disperser solvent. The parameters, which may influence the extraction efficiency such as the types and volumes of extraction solvent and disperser solvent, extraction time, sample pH, centrifugation time and salting-out effect, have been investigated. Under optimal conditions, there was a good linear relationship in the concentration range 0.25-50, 0.5-100, 0.75-150, and 1.5-300 mu g L-1 for 2,4-dinitrophenol, 2-naphthol, 1-naphthol and bisphenol A, respectively. The limits of detection based on the ratio of signal-to-noise were equal to three (LODs, S/N = 3) in the range 0.11-0.62 mu g L-1. Precision of the proposed method (RSDs, n = 6) were in the range 2.6-9.3%. The experimental results demonstrated that the present method lowered the LOQs compared to that of most existing methods and provided a simple and rapid analytical procedure. The analysis of real water samples spiked with two different concentrations resulted in good spiked recoveries in the range 86.8-118%. These results indicated that the proposed method would be competitive for the analysis of phenols.