Modified SBA-15 mesoporous silica as a novel fiber coating in solid-phase microextraction and determination of BTEX compounds in water samples using gas chromatography-flame ionization detection

Nanoporous silica (SBA-15) was prepared, functionalized with 3-(2-aminoethylamino) propyltrimethoxysilane and employed as a novel solid-phase microextraction (SPME) fiber. The prepared nanoporous silica was immobilized onto a copper wire for fabrication of the SPME fiber. The efficiency and reliability of the prepared device was investigated for the extraction of some volatile organic compound such as benzene, toluene, ethylbenzene and xylenes from the headspace of sample solutions. Five experimental parameters consisting of adsorption temperature, adsorption time, stirring rate, salt concentration and headspace volume were evaluated and optimized by using a Taguchi's L-16 (4(5)) orthogonal array experimental design. Under the optimized conditions for all BTEX compounds, the repeatability for one fiber (n = 4), expressed as relative standard deviation was between 5.2 and 9.8% and the reproducibility for four fibers was between 6.83% and 10.9%, the linearity was from 1.5 to 950 mu g L-1 and the limit of detection was between 0.15 and 0.42 mu g L-1. The recovery values were 83.7 to 108.2% for water samples. The proposed method was applied in the determination of the trace level compounds in natural water samples.