GAS-CHROMATOGRAPHIC DETERMINATION OF 5-CHLORO-2-(2,4-DICHLOROPHENOXY)-PHENOL IN THE WASTE-WATER OF A SLAUGHTERHOUSE

A straightforward analytical method for the determination of 5-chloro-2-(2,4-dichlorophenoxy)-phenol (commercially known as Irgasan DP 300) in the waste water of a slaughterhouse was developed. The waste water, first cleaned from fats and oils by petroleum ether (b.p. 40-80 degrees C) at pH 11, was extracted by benzene at pH 1 and this Irgasan-containing extract, was further purified by sodium sulfate/silica gel adsorption. After preconcentration and diazomethane derivatization of the extract, capillary GC-ECD determination was applied. The procedure yields a routine recovery of 88.1% regardless of the sample concentration. The lower detection limit for Irgasan in the waste water was found to be 8.2 ng l(-1).