An analytical method has been developed to determine long-chain n -alkan-2-ones (C-10-C-33 ) in atmospheric particulate matter. This involves (1) solvent extraction with a Dionex Accelerated Solvent Extractor (ASE 200), followed by nitrogen blowdown; (2) a clean-up procedure using silica-gel chromatography to separate fractions of different polarities; and (3) gas chromatography with mass-selective detector (GC/MSD) identification and gas chromatography with flame ionization detector (GC/FID) quantitation. The recovery rates in the extraction/blowdown steps were quantified at different extraction and blowdown temperatures. The maximum recoveries for the selected ketones, obtained at 40degreesC for both extraction and blowdown, are 70-100% for the extraction step and 92-101% for the combined steps of blowdown and silica gel separation depending on the chain length of the ketones. The overall analytical instrumental detection limits for the ketones are <0.24 ng/muL in the GC/FID.
The degradation characteristics of four phthalic acid esters (PAEs), i.e. di-methyl phthalate (DMP), di-ethyl phthalate (DEP), di-n-butyl phthalate (DBP) and di-n-octyl phthalate (DOP) in the soil augmented with acclimated sludge was investigated in order to assess the efficacy of bioaugmentation as a strategy for remediating PAEs-contaminated soil and correlate the degradation rate of PAEs with their alkyl chain length. The results demonstrated that PAEs with shorter alkyl chain, that is, DMP and DEP could be degraded more quickly than DBP and DOP. The degradation of four PAEs in the soil conformed to a first-order reaction kinetic equation. The half-lives of PAEs degradation decreased significantly with increasing carbon number of the alcohol moiety. Half-lives decreased from 2.29 days for DMP to 28.4 days for DOP when the carbon number of alkyl chain increased from one for DMP to eight for DOP. The degradation rate of PAEs and the corresponding half-lives could correlate with the alkyl chain length and their octanol-water partition coefficients (K,,) quite well for the four PAEs tested in this study. (C) 2003 Elsevier Ltd. All rights reserved.