title: Microwave-assisted steam distillation with simultaneous liquid/liquid extraction of pentachlorophenol from organic wastes and soils.
abstract: An efficient method for extracting pentachlorophenol (PCP) from organic solid matrices and soils using direct excitation of the fresh samples by microwave energy is presented. Steam-volatile PCP partitioned into the organic solvent n-hexane within the closed extraction vessel, resulting in recovery rates of 85-92% from aged samples. Condensed water provided a boundary layer between extract and sample thus preventing any contact of PCP with and re-partitioning into the sample. Duration of the microwave-assisted process was 35 min. Crude extracts were derivatized by heptafluorobutyric anhydride (HFBA) to improve selectivity and sensitivity resulting in detection limits of 1-2 micro g kg(-1). GC-MS/MS analyses proved that suitable extracts with only minor impurities were obtained. Common sample treatment steps like drying, thorough grinding, frequent transferring, and tedious clean-up, and concentration procedures which all can cause certain losses of analyte were minimized. The efficiency of the method was verified by comparison with an established ultrasonic extraction procedure. This microwave-assisted pressurized steam distillation with simultaneous partition into an organic phase thus provides a streamlined and efficient strategy which requires no additional investment in standard equipment for microwave-assisted extractions (MAE). Degradation of analytes at longer extraction times must be taken into account.
authors.affiliation: Institute of Landscape Ecology and Resources Management, Division of Waste Management and Environmental Research, Justus-Liebig-University, Heinrich-Buff-Ring 26-32, 35392, Giessen, Germany. rolf-alexander.duering@agrar.uni-giessen.de
authors.forename: Rolf-Alexander
authors.initials: RA
authors.lastname: Düring
authors.forename: Xiaolei
authors.initials: X
authors.lastname: Zhang
authors.forename: Hans E
authors.initials: HE
authors.lastname: Hummel
authors.forename: Janusz
authors.initials: J
authors.lastname: Czynski
authors.forename: Stefan
authors.initials: S
authors.lastname: Gäth
mesh_terms: D005591:Chemical Fractionation; D004785:Environmental Pollutants / Q000302:isolation & purification*; D006801:Humans; D007220:Industrial Waste / Q000032:analysis; D008872:Microwaves; D010416:Pentachlorophenol / Q000302:isolation & purification*; D012722:Sewage / Q000032:analysis; D012987:Soil / Q000032:analysis; D013227:Steam
chemical_list: D004785:Environmental Pollutants; D007220:Industrial Waste; D012722:Sewage; D012987:Soil; D013227:Steam; D010416:Pentachlorophenol