Ionic Liquid-Mediated Multi-Walled Carbon Nanotube-Polydimethylsiloxane Fiber for Headspace Solid-Phase...

An ionic liquid-mediated multi-walled carbon nanotube (MWCNT)-polydimethylsiloxane (PDMS) sorbent was developed for headspace solid-phase microextraction (HS-SPME) of phenolic compounds from human urine samples. Sol-gel method was used to prepare this sorbent. For this purpose, MWCNTs were functionalized covalently and were attached chemically to the hydroxyl-terminated PDMS. Prepared fiber showed high thermal stability (over than 320°C) and good lifespan (>210 times). These good performances can be attributed to the performance of carbon nanotubes and sol-gel method. Affecting parameters on the efficiency of HS-SPME were investigated and optimized. Under the optimal conditions, linear dynamic ranges were observed over a range of 0.002-200 ng mL^-1 with limits of detection from 0.0005 to 0.005 ng mL^-1 and limits of quantitation between 0.002 and 0.02 ng mL^-1 The relative standard deviations for one fiber (repeatability) (n = 5) at three different concentrations (0.05, 2 and 100 ng mL^-1) were obtained from 4.6 up to 6.7% and between fibers or batch to batch (n = 3) (reproducibility) in the range of 5.7-7.8%. Urine samples were used as real samples. All real samples were spiked at 0.5 ng mL^-1 of understudy analytes and the relative recovery percentages obtained from 90.7 to 102.1%.