A Modified Nanoporous Silica Aerogel as a New Sorbent for Needle Trap Extraction of Chlorobenzenes from Water Samples

In this work, a modified nanoporous silica aerogel was used as a new sorbent for headspace needle trap extraction of chlorobenzenes from aqueous samples. The needle trap extraction is derived from solid-phase microextraction and the sorbent is inside the needle. The thermal stability and functional groups of the sorbent were studied by TG/DTA and FT-IR, respectively. The modified silica aerogels, characterized by field emission scanning electron microscopy, showed a three-dimensional network containing a homogeneous pore structure with pore sizes of a few tens of nm and a sponge-like microstructure. The developed method was applied to the trace level extraction of some chlorobenzene compounds from aqueous samples. The influential parameters on the extraction efficiency, including the extraction temperature, ionic strength and extraction time were investigated and optimized. Under optimized conditions, the detection and quantification limits were in the range of 0.4-0.8 and 1-3 ng L-1, respectively. The relative standard deviation values for water spiked with chlorobenzenes at 100 ng L-1 under optimum conditions were 3-7%. The dynamic linear range of the method in the range of 3-3000 ng L-1 was investigated. Finally, the current method for the analysis of real water samples containing spiked chlorobenzenes was applied and the relative recovery values were found to be in the range of 96-101%.