Microwave-assisted steam distillation with simultaneous liquid/liquid extraction of pentachlorophenol from organic wastes and soils.
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.
Düring
Rolf-Alexander
RA
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
Zhang
Xiaolei
X
Hummel
Hans E
HE
Czynski
Janusz
J
Gäth
Stefan
S
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
D004785:Environmental Pollutants; D007220:Industrial Waste; D012722:Sewage; D012987:Soil; D013227:Steam; D010416:Pentachlorophenol