Determination of priority phenolic compounds in water and industrial effluents by polymeric liquid-solid extraction cartridges using automated sample preparation with extraction columns and liquid chromatography - Use of liquid-solid extraction cartridges for stabilization of phenols

Fourteen phenolic compounds: catechol, phenol, 4-nitrophenol, 4-methylphenol, 2,4-dinitrophenol, 2-nitrophenol, 2-chlorophenol, 4-chlorophenol, 3-chlorophenol, 4-chloro-3-methylphenol, 2,4-dimethylphenol, 2,4-dichlorophenol, 2,4,6-trichlorophenol and pentachlorophenol, which are included in the priority pollutants list of the US Environmental Protection Agency and in the European Union list 76/464, were determined in water by liquid-solid extraction (LSE) followed by liquid chromatography with UV detection (LC-UV). Three different polymeric sorbents were used: Isolute ENV+, Lichrolut EN and Porapak RDX. The developed method involves the use of automated sample preparation with extraction columns (ASPEC XL) for automated sample preconcentration and a Baker LSE 12G apparatus with the vacuum set at 15 p.s.i. (1 p.s.i.=6894.76 Pa) for the drying step. The recoveries varied from 70 to 100% (except for catechol) on preconcentrating 700-1000 ml of a 5 mu g/l solution, pH 2.5-3. The stability of the target compounds on Isolute ENV+ was evaluated by storing the sorbent material at -20 degrees C, 4 degrees C and at room temperature for up to three months. Complete recovery was observed after storage at -20 degrees C for two months, At room temperature, losses of up to 70% were observed for phenol, catechol and the more volatile phenols. The stability of the phenolic compounds was dependent on the water matrix, the storage temperature and on physico chemical properties, such as vapor pressure and water solubility. (C) 1997 Elsevier Science B.V.