Silica aerogel coated on metallic wire by phase separation of polystyrene for in-tube solid phase microextraction

Abstract

In this research, an attempt was made toward synthesizing a sol-gel-based silica aerogel and its subsequent coating on a copper wire by phase separation of polystyrene. Adaption of this new approach enabled us to coat the metallic wire with powder materials. The use of this method for coating, led to the formation of a porous and thick structure of silica aerogel. The coated wire was placed in a needle and used as the sorbent for in-tube solid phase microextraction of chlorobenzenes (CBs). The superhydrophobicity of sorbent on extraction efficiency was investigated by using different ratios of tetraethylorthosilicate/methyltrimethoxysilane. The surface coated with the prepared silica aerogel by the phase separation of polystyrene showed high contact angle, approving the desired superhydrophobic properties. Effects of major parameters influencing the extraction efficiency including the extraction temperature, extraction time, ionic strength, desorption time were investigated and optimized. The limits of detection and quantification of the method under the optimized condition were 0.1-1.2 and 0.4-4.1ngL^-1, respectively. The relative standard deviations (RSD%) at a concentration level of 10ngL^-1 were between 4 and 10% (n=3). The calibration curves of CBs showed linearity from 1 to100ngL^-1. Eventually, the method was successfully applied to the extraction of model compounds from real water samples and relative recoveries varied from 88 to 115%.

Keywords: Gas chromatography–mass spectrometry; In–tube microextraction; Phase separation; Silica aerogel; Sol–gel process; Superhydrophobicity.