Further investigation of array capillary in-tube solid-phase microextraction of trace organic pollutants in water samplesf

摘要

Array capillary in-tube solid-phase microextraction (AC1T-SPME) was demonstrated to be a fast, reproducible and convenient extraction method for trace organic pollutants in water samples. In order to improve the extraction efficiency per unit of extraction time, ACIT-SPME cartridges with capillary tubes of different inner diameters (I.D.), from 0.1 mm to 0.5 mm I.D., were fabricated and compared systematically for the extraction of chlorobenzenes (CBs) and nitrochlorobenzenes (NCBs). The results indicated that the ACIT-SPME cartridges with the largest bore diameter were more suitable for rapid extraction of analytes in abundant water samples, while the ACIT-SPME with the smallest bore diameter resulted in the highest absolute recovery. Thus, ACIT-SPME capillary tubes of 0.5 mm I.D. were applied in the rapid extraction of CBs and NCBs from environmental water. Parameters such as sample volume, extraction time, ionic strength, and thermal desorption conditions were investigated to obtain the optimal operation conditions. The extraction was completed in 1.5 min under gravity using 250 mL of water sample. The desorbed analytes were analyzed by gas chromatography (GC) coupled with electron capture detection (ECD). A linear relationship between the peak areas and the concentrations of the analytes covered 2 orders of magnitude with correlation coefficients higher than 0.9961 for all the compounds being studied. The detection limits were between 0.00041 and 0.047 μg L~(-1) with a relative standard deviation (RSD) of between 1.4% and 4.8%. The proposed method was applied in the extraction and determination of CBs and NCBs in real water samples. Relative recoveries and RSDs for the analysis of real water samples were 87.1-116% and 1.8-9.4%, respectively. These results further proved that ACIT-SPME could be applied as a routine sample preparation method for water analysis both in the field and in the lab.