title: Coupled two-step microextraction devices with derivatizations to identify hydroxycarbonyls in rain samples by gas chromatography-mass spectrometry.
abstract: Coupling a two-step liquid-phase microextraction (LPME) with O-(2,3,4,5,6-pentafluorobenzyl)-hydroxylamine/bis(trimethylsilyl)trifluoroacetamide (PFBHA)/(BSTFA) derivatization was developed to detect hydroxycarbonyls in rainwater samples using gas chromatography-mass spectrometry (GC-MS). LPME provides a fast and inexpensive pre-concentration, and miniaturized extraction to analyze the target compounds rainwater samples. Derivatization techniques offer a clear method to identify target compounds. The hydroxycarbonyls were determined using two-step derivatizations. Dynamic-LPME was applied in the first derivatization, and head-space single drop derivatization was employed in the second reaction. The LODs varied from 0.023 to 4.75 microg/l. The calibration curves were linear for at least two orders of magnitude with R2>or=0.994. The precision was within 6.5-12%, and the relative recoveries in rainwater were more than 89% (the amount added ranged from 0.3 to 15 microg/l). A field sample was found to contain 2.54 microg/l of hydroxyacetone and 0.110 microg/l of 3-hydroxy-2-butanone. Hydroxyacetone was also detected in one of the tested samples at a concentration of 2.39 microg/l.
authors.affiliation: Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan.
authors.forename: Pai-Shan
authors.initials: PS
authors.lastname: Chen
authors.forename: Shang-Da
authors.initials: SD
authors.lastname: Huang
mesh_terms: D002138:Calibration; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D007659:Ketones / Q000032:analysis*; D011891:Rain / Q000737:chemistry*; D012680:Sensitivity and Specificity; D013696:Temperature
chemical_list: D007659:Ketones