An organically modified silica aerogel for online in-tube solid-phase microextraction

•An organically modified silica aerogel was developed as the coating for IT-SPME.•Basalt fiber was modified with aerogel coating by a facile method.•IT-SPME device was easily connected into HPLC for online analysis.•IT-SPME device showed good durability, repeatability and extraction selectivity.•Online analysis method was built and applied to the detection of estrogens in water samples.

Aerogels have received considerable attentions because of its porous, high specific surface, unique properties and environmental friendliness. In this work, an organically modified silica aerogel was functionalized on the basalt fibers (BFs) and filled into a poly(ether ether ketone) (PEEK) tube, which was coupled with high performance liquid chromatography (HPLC) for in-tube solid-phase microextraction (IT-SPME). The aerogel was characterized by scanning electron microscopy (SEM) and fourier transform infrared spectrometry (FT-IR). The extraction efficiency of the tube was systematically investigated and shown enrichment factors from 2346 to 3132. An automated, sensitive and selective method was developed for the determination of five estrogens. The linear range was from 0.03 to 100 μg L−1 with correlation coefficients (r) higher than 0.9989, and low detection limits (LODs) were 0.01-0.05 μg L−1. The relative standard deviations (RSDs) for intra-day and inter-day were less than 4.5% and 6.7% (n = 6), respectively. Finally, the analysis method was successfully applied to detect estrogens in sewage and emollient water samples.