Determination of phenolic xenoestrogens in water by liquid chromatography with coulometric-array detection

A sensitive method for the simultaneous determination of phenolic xenoestrogens such as bisphenol A, 2,4-dichlorophenol, 4-tert.-butylphenol, 4-n-pentylphenol, 4-n-hexylphenol, 4-n-heptylphenol, 4-octylphenol, 4-nonylphenol was developed using reversed-phase LC and coulometric-array detection. Stepwise gradient elution with phosphoric acid in water–acetonitrile was used. The calibration curves were linear in the range of 5.0 (or 10.0)–1000 ng ml−1 with correlation coefficients of 0.9978–0.9999, the limits of detection were 0.01–0.02 ng ml−1. Sample clean-up was performed by solid-phase extraction (SPE) using 3M Empore™ extraction disks. Three commercial sorbents, C18, SDB-XD (styrene–divinylbenzene polymer) and SDB-RPS (sulfonated styrene–divinylbenzene polymer) were compared. The highest recoveries were obtained with SDB-RPS. They were above 70% with a relative standard deviation of less than 15%. The proposed method was applied to the determination of phenolic xenoestrogens in various water samples.