title: Microwave-assisted phase-transfer catalysis for the rapid one-pot methylation and gas chromatographic determination of phenolics.
abstract: Microwave-assisted phase-transfer catalysis (PTC) is reported for the first time, for the one-step extraction-derivatization-preconcentration and gas chromatographic determination of twenty phenols and ten phenolic acids. The well established phase-transfer catalytic methylation is largely accelerated when heating is replaced with the "greener" microwave irradiation. The overall procedure was thoroughly optimized and the analytes were determined by GC/MS. The method presented adequate analytical characteristics being more sensitive in analyzing phenols than phenolic acids. The limits of detection without any additional preconcentration steps (e.g. solvent evaporation) were adequate and ranged from 0.4 to 15.8ng/mL while limits of quantitation were between 1.2 and 33.3ng/mL. The method was applied to the determination of phenols, in spiked environmental samples and phenolic acids in aqueous infusions of commercially available pharmaceutical dry plants. The recoveries of fortified composite lake water samples and Mentha spicata aqueous infusions ranged from 89.3% to 117.3% for phenols and 93.3% to 115.2% for phenolic acids.
authors.affiliation: Laboratory of Analytical Chemistry, Department of Chemistry, University of Ioannina, Ioannina 45110, Greece. yfiameg@cc.uoi.gr
authors.forename: Yiannis C
authors.initials: YC
authors.lastname: Fiamegos
authors.forename: Andreas
authors.initials: A
authors.lastname: Karatapanis
authors.forename: Constantine D
authors.initials: CD
authors.lastname: Stalikas
mesh_terms: D005591:Chemical Fractionation / Q000379:methods*; D002849:Chromatography, Gas / Q000379:methods*; D052244:Endocrine Disruptors / Q000032:analysis; D005618:Fresh Water / Q000737:chemistry; D062385:Hydroxybenzoates / Q000032:analysis*; D031337:Mentha spicata / Q000737:chemistry; D008745:Methylation; D008872:Microwaves; D010636:Phenols / Q000032:analysis*; D010936:Plant Extracts / Q000737:chemistry; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012722:Sewage / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D052244:Endocrine Disruptors; D062385:Hydroxybenzoates; D010636:Phenols; D010936:Plant Extracts; D012722:Sewage; D014874:Water Pollutants, Chemical; C017616:phenolic acid