Hollow-fiber-supported liquid phase microextraction with in situ derivatization and gas chromatography–mass spectrometry for determination of chlorophenols in human urine samples

A simple and highly sensitive method that involves hollow-fiber-supported liquid phase microextraction (HF-LPME) with in situ derivatization and gas chromatography–mass spectrometry (GC–MS) was developed for the determination of chlorophenols (CPs) such as 2,4-dichlorophenol (DCP), 2,4,6-trichlorophenol (TrCP), 2,3,4,6-tetrachlorophenol (TeCP) and pentachlorophenol (PCP) in human urine samples. Human urine samples were enzymatically de-conjugated with β-glucuronidase and sulfatase. After de-conjugation, HF-LPME with in situ derivatization was performed. After extraction, 2 μl of extract was carefully withdrawn into a syringe and injected into the GC–MS system. The limits of detection (S/N = 3) and quantification (S/N > 10) of CPs in the human urine samples are 0.1–0.2 ng ml−1 and 0.5–1 ng ml−1, respectively. The calibration curve for CPs is linear with a correlation coefficient of >0.99 in the range of 0.5–500 ng ml−1 for DCP and TrCP, and of 1–500 ng ml−1 for TeCP and PCP, respectively. The average recoveries of CPs (n = 6) in human urine samples are 81.0–104.0% (R.S.D.: 1.9–6.6%) with correction using added surrogate standards. When the proposed method was applied to human urine samples, CPs were detected at sub-ng ml−1 level.