An organic-inorganic hybrid silica aerogel prepared by co-precursor method for solid-phase microextraction coating.

In order to improve the extraction performance of silica aerogel, an organic-inorganic hybrid silica aerogel was developed as the coating of solid-phase microextraction (SPME). It was prepared via the co-precursor reaction between tris(triethoxysilylpropyl)amine and tetraethyl orthosilicate. Coupled with gas chromatography, the hybrid silica aerogel-coated SPME fiber was evaluated using polycyclic aromatic hydrocarbons (PAHs). Compared to silica aerogel, the hybrid silica aerogel displayed better extraction performance, peak areas of PAH analytes were increased by about 2 times. The affecting parameters including extraction time, extraction temperature, ionic strength, stirring rate and desorption time were optimized, and an analytical method was established with wide linear ranges (0.005-20 μg L-1, 0.010-20 μg L-1, 0.100-20 μg L-1), good correlation coefficients (0.9967-0.9994), low limits of detection (0.001-0.030 μg L-1) and limits of quantitation (0.005-0.100 μg L-1). Satisfactory extraction repeatability (RSD≤6.1%, n = 3) and preparation repeatability (RSD ≤ 9.8%, n = 3) were also obtained. Compared to the reported coatings and the commercial coating, the organic-inorganic hybrid silica aerogel has higher or comparable sensitivity, better repeatability, and shorter extraction time and longer service life. The established method was used for the detection of lake water and rain water, and some targets were quantified successfully.