Investigation of Pencil Leads Fiber Efficiency for SPME of Trace Amount of Methamphetamine from Human Saliva Prior to GC-MS Analysis

The efficiency of pencil lead fiber was investigated for effective head-space solid-phase microextraction (HS-SPME) of methamphetamine (MAMP) from aqueous standard solutions without chemical derivatization prior to gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) analyses. Most effective experimental parameters such as extraction temperature and time, sample pH, and salting out were studied and optimized. At the optimum conditions, the efficiency of this fiber was compared with polyacrylate (PA) commercial fiber, which is most selective for volatile and semi-volatile compounds. The results obtained prove the suitability of modified pencil-lead fiber for sampling of the studied compound from aqueous solutions. Under optimum conditions, the calibration plot was linear in the range of 40-8000 ng/mL (r = 0.998), and the detection limit was 27 ng/mL (n = 3). The proposed method was successfully applied for HS-SPME of MAMP from 200 mu L human saliva, which has been spiked with trace amounts of MAMP (160 ng/mL) followed by GC-MS monitoring.