Jd. Berset et R. Etter-holzer, Determination of phthalates in crude extracts of sewage sludges by high-resolution capillary gas chromatography with mass spectrometric detection, J AOAC INT, 84(2), 2001, pp. 383-391
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.