Micro-solid phase extraction of benzene, toluene, ethylbenzene and xylenes from aqueous solutions using water-insoluble β-cyclodextrin polymer as sorbent

Water-insoluble β-cyclodextrin polymer was synthesized by chemical cross-linking using epichlorohydrin (EPI) as a cross-linker agent. The produced water-insoluble polymer was used as a sorbent for the micro-solid phase extraction (μ-SPE) of benzene, toluene, ethylbenzene and xylenes (BTEX) from water samples. The μ-SPE device consisted of a sealed tea bag envelope containing 15 mg of sorbent. For the evaluation of the extraction efficiency, parameters such as extraction and desorption time, desorption solvent and salt concentration were investigated. At an extraction time of 30 min in the course of the extraction process, analytes were extracted from a 10 mL aqueous sample solution. The analytes were desorbed by ultrasonication in 200 μL of acetonitrile for 20 min. Analysis of the analytes was done by a gas chromatography-flame ionization detector (GC-FID) system. The enrichment factor (EF) was found to be in the range 23.0-45.4 (EFmax = 50.0). The method provided linearity ranges of between 0.5 and 500.0 ng/mL (depending on the analytes), with good coefficients of determination (r2) ranging between 0.997 and 0.999 under optimized conditions. Detection limits for BTEX were in the range of between 0.15 and 0.60 ng/mL, while corresponding recoveries were in the range of 46.0-90.0%. The relative standard deviation of the method for the analytes at 100.0 ng/mL concentration level ranged from 5.5 to 11.2% (n = 5). The proposed method was concluded to be a cost effective and environmentally-friendly extraction technique with ease of operation and minimal usage of organic solvent.