title: Fast miniaturised sample preparation for the screening and comprehensive two-dimensional gas chromatographic determination of polychlorinated biphenyls in sludge.
abstract: Polychlorinated biphenyls (PCBs) in sludge are usually extracted by a technique such as Soxhlet with subsequent fractionation prior to long GC runs using GC-ECD or GC-HRMS. In this study, the extraction of selected chlorinated biphenyls (CBs) from a spiked sludge sample by three rapid techniques, i.e. ultrasonic (USE), pressurised-liquid (PLE), and microwave-assisted (MAE) extraction using a domestic microwave, was studied, with subsequent direct GC-ECD, GC-MS, or GC x GC-microECD analysis of the extracts. The main goal was to select an appropriate, and miniaturised, extraction method after only a brief optimisation and demonstrate the power of GC x GC analysis of dirty extracts. For PLE similar CB recoveries were found when extracting with either n-hexane or n-hexane/acetone (1/1). For USE and MAE, n-hexane/acetone (1/1) was the preferred extraction solvent. USE gave the best recoveries (80-95%; except 130% for CB 105). The only clean-up needed prior to GC-MS or GC x GC-gECD analysis was the removal of sulphur-containing compounds. GC-ECD was not suitable for these dirty extracts. The lowest LODs for the CBs (20 fg or 0.1 ng/g sludge) were found when combining USE and GC x GC-microECD, because of the powerful extraction, high separation power and excellent detectability provided by this technique.
authors.affiliation: Vrije Universiteit, Department of Analytical Chemistry and Applied Spectroscopy, de Boelelaan 1083,1081 HV Amsterdam, The Netherlands. maria.kristenson@neoresins.com
authors.forename: E Maria
authors.initials: EM
authors.lastname: Kristenson
authors.forename: Harmen C
authors.initials: HC
authors.lastname: Neidig
authors.forename: René J J
authors.initials: RJ
authors.lastname: Vreuls
authors.forename: Udo A Th
authors.initials: UA
authors.lastname: Brinkman
mesh_terms: D002138:Calibration; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D011078:Polychlorinated Biphenyls / Q000032:analysis* / Q000302:isolation & purification*; D012722:Sewage / Q000032:analysis* / Q000737:chemistry
chemical_list: D012722:Sewage; D011078:Polychlorinated Biphenyls