Inside-tube solid-phase microextraction as an interlink between solid-phase microextraction and needle device for n-hexane evaluation in air and urine headspace

Monitoring the trace amount of chemicals in various samples remains a challenge. This study was conducted to develop a new solid-phase microextraction (SPME) system (inside-tube SPME) for trace analysis ofn-hexane in air and urine matrix. The inside-tube SPME system was prepared based on the phase separation technique. A mixture of carbon aerogel and polystyrene was loaded inside the needle using methanol as the anti-solvent. The air matrix ofn-hexane was prepared in a Tedlar bag, andn-hexane vapor was sampled at a flow rate of 0.1 L/min. Urine samples spiked withn-hexane were used to simulate the sampling method. The limit of detection using the inside-tube SPME was 0.0003 mu g/sample with 2.5 mg of adsorbent, whereas that using the packed needle was 0.004 mu g/sample with 5 mg of carbon aerogel. Forn-hexane analysis, the day-to-day and within-day coefficient variation were lower than 1.37%, with recoveries over 98.41% achieved. The inside-tube SPME is an inter-link device between two sample preparation methods, namely, a needle trap device and an SPME system. The result of this study suggested the use of the inside-tube SPME containing carbon aerogel (adsorbent) as a simple and fast method with low cost forn-hexane evaluation.