Extraction of carbonyl derivatives from ozonated wastewater samples using hollow fiber liquid phase microextraction followed by gas chromatography-electron capture detection

摘要

Herein, a simple and sensitive method was successfully developed for the extraction and quantification of seven carbonyl compounds (acetaldehyde, propanal, butanal, pentanal, hexanal, glyoxal, methylglyoxal) in a number of wastewater samples previously treated by ozonation process. The compounds were initially derivatized (derivatizing reagent (PFBHA)) and then extracted by a hollow-fiber liquid-phase microextraction method (HF-LPME) in the aqueous sample solution. Afterwards, the extraction solvent was withdrawn from the fiber and injected to a gas chromatograph equipped with electron capture detection (GC-ECD). Factors affecting the extraction efficiency of the whole procedure were optimized using a univariate approach. Under the optimal conditions obtained (sample solution pH, 4; organic extraction solvent, dihexylether; stirring rate, 1000 rpm; no salt addition; and extraction time of 40 min), limits of quantification were 0.5-0.8 mu g/l for the studied carbonyl compounds. Dynamic linear ranges were 0.5-100 mu g/l for five targets (acetaldehyde, propanal, butanal, pentanal and hexanal) and 0.8-80 mu g/l for two targets (glyoxal and methylglyoxal). The relative standard deviations (RSDs %) representing the precision of the method were in the range of 6.4-11.9 based on the average of three measurements. Accuracy of the method was also tested by the relative recovery experiments on spiked samples, with results ranging from 85 to 113%. Finally, the method could be used for routine screening of carbonyl compounds in complex matrices.