Determination Of Semivolatile Organic Compounds In Water Samples By Dispersive Liquid-Liquid Microextraction With GC/MS

Abstract Dispersive liquid-liquid microextraction (DLLME) was developed in 2006, which is based on a ternary component solvent system. DLLME has become a very popular environmentally benign sample-preparation technique, because it is fast, inexpensive, easy to operate with a high enrichment factor and consumes low volume of organic solvent. At present, the DLLME technique has been widely applied in various fields, such as environment, food, biology, drug analysis, etc.The studies of this paper focus on the followings:In the first part of this thesis, the progress of sample pretreatment technologies is summarized. A detailed review concerning on the development of DLLME and its applications and developments are presented.In the second part,a novel method for the determination of 64 semivolatile organic compounds (SVOCs) in water samples by DLLME coupled with gas chromatography-mass spectrometry (GC-MS) was developed. Parameters affecting the extraction efficiency (i.e., types and volumes of extraction and dispersive solvents, sample ionic strength, and extraction time and mode) were investigated and discussed in detail. Under optimized conditions, the enrichment factors ranged from 84 to 475. Linearity varied from 0.05 to 100μg/L. The relative standard deviations (RSDs) ranged from 4.1% to 14.7% (n=6). The limits of detection (LODs), based on a signal-to-noise ratio (S/N) of 3, varied from 0.003 to 0.2μg/L. The relative recovery (RR) in the river water and lake water were between 94.6% and 109.5% and between 91.5% and 107.0%, respectively.In the third part, application of DLLME-GC-MS on the determination of three pyrethroid pesticides (bifenthrin, cypermethrin and deltamethrin) in water samples was studied. Extraction conditions and GC-MS conditions were optimized by experiments. Under optimized conditions, the enrichment factors ranged from 318 to 363. Linearity varied from 0.05~50μg/L and 0.5~100μg/L, respectively. The limits of detection (LODs), based on a signal-to-noise ratio (S/N) of 3, varied from 0.002 to 0.04μg/L. The relative standard deviations (RSDs) ranged from 3.7% to 11.2% (n=6). The relative recovery (RR) in the river water and lake water were between 86.0%~117.0%.This method can be used as an alternative approach for determining trace levels of SVOCs in water samples.