Simulanteous extraction and determination of carbonyl compounds in ozonated water samples via derivatization using hollow fiber liquid phase microextraction followed by gas chromatography-electron capture detection

Ozonation is regarded as the most popular and effective oxidation process in waste water treatment technology. Ozone reacts with natural organic substances present in water to produce a number of corresponding by-products [1]. The common by-products are short-chained carbonyl compounds such as aldehyde and ketones [2-4]. They are highly volatile and can cause severe respiratory and health-related problems [5]. The present study has centered on the development of a sensitive and reliable HF-LPME method for the GC-ECD quantification of PFBHA-oxime derivatives of selected carbonyl compounds generated following ozonation of the waste water samples. Screening and optimization of the parametrs affecting the HF-LPME procedure such as temperature of solution, stirring rate, extraction time, salt addition and pH of solution was performed by a fractional factorial design and a subsequent central composite design (CCD). Under the optimal conditions (sample solution temperature, 50°; stirring rate, 1000 rpm; pH, 5; salt addition, 4% w/w; and 40 min, extraction time), limits of quantification and dynamic linear ranges of 10-25 ng/ml and 10–500 ng/ml were obtained for the studied carbonyl compounds, respectively. The relative standard deviations (RSDs %) representing the precision of the method were in the range of 4.2-13.8 based on the average of five measurements. Accuracy of the method was also tested by the relative recovery experiments on spiked samples, with results ranging from 87 to 115 %. Finally, the method proved to be simple, rapid, and cost-effective for routine screen of carbonyl compounds in highly complicated ozone-treated waste water samples.