Determination of phthalates in crude extracts of sewage sludges by high-resolution capillary gas chromatography with mass spectrometric detection

A simple solvent extraction by ethyl acetate without subsequent cleanup was used to determine 16 phthalic acid esters (PAEs), including bis(a-ethylhex yl) phthalate (DEHP), in sewage sludge samples from different catchment are as. The compounds were separated on a gas chromatographic capillary column with a nonpolar HT-8 stationary phase. For most of the PAEs, internal stand ard quantification with deuterated dibutyl phthalate (DBP) and deuterated D EHP was best achieved by using electron ionization mass spectrometry in the selected-ion monitoring mode, Because of its high concentrations in the sl udges, DEHP was quantified in the full-scan acquisition mode, Molecular wei ght and ester-type information for the PAEs was obtained in the positive ch emical ionization mode with methane as the reagent gas. Finally, selected s ewage sludges containing different amounts of industrial wastewater were an alyzed by the proposed method. DEHP was the most abundant compound found at 21-114 mg/kg(.)dm, followed by the lower-molecular weight PAEs diethyl pht halate, diisobutyl phthalate, and DBP and the higher-molecular weight compo unds butylbenzyl phthalate, dicyclohexyl phthalate, di-n-octyl phthalate, a nd dinonyl phthalate, which were present mostly at <1 mg/kg(.)dm.