In situ hydrothermal growth of polyaniline coating for in-tube solid-phase microextraction towards ultraviolet filters in environmental water samples

•The basalt fiber with excellent environmental and chemical properties was first used for in-tube SPME.•The polyaniline coating was first grown on the basalt fiber by in situ hydrothermal.•This method showed high extraction efficiency compared with other reported methods.•The fibers-in-tube SPME extraction device is shown good durability and repeatability.

A facile, low cost, sensitive and environmentally friendly polyaniline (PANI) coating was prepared onto the basalt fibers (BFs) by in situ hydrothermal growth method. PANI functionalized BFs were placed into a poly(ether ether ketone) (PEEK) tube as a fibers-in-tube solid-phase microextraction (SPME) device. The extraction and analysis processes were carried out by connecting it to high performance liquid chromatography (HPLC). Three ultraviolet filters including 2-hydroxy-4-methoxybenzophenone, phenyl salicylate and 2,4-dihydroxybenzophenone were employed as model analytes. Under the optimal extraction and desorption conditions, online in-tube SPME-HPLC analysis method was established and afforded satisfactory enrichment factors (1323-1555), wide linear ranges (0.06-100 μg L−1) with correlation coefficients ranging from 0.9995 to 0.9999, low limits of detection (0.02-0.05 μg L−1) and acceptable extraction repeatability (RSD < 7.8%, n = 6) and preparation repeatability (RSD < 9.7%, n = 3). The proposed method was successfully applied to the determination of the three ultraviolet filters in two environmental water samples.