Preparation of ionic liquid based solid-phase microextraction fiber and its application to forensic determination of methamphetamine and amphetamine in human urine.
A new solid-phase microextraction (SPME) procedure using an ionic liquid (IL) has been developed. Reusable IL-based SPME fiber was prepared for the first time by fixing IL through cross-linkage of IL impregnated silicone elastomer on the surface of a fused silica fiber. 1-Ethoxyethyl-3-methylimidazloium bis(trifluoromethane) sulfonylimide ([EeMim][NTf(2)]) ionic liquid was employed as a demonstration and the prepared fiber was applied to the forensic headspace determination of methamphetamine (MAP) and amphetamine (AP) in human urine samples. Important extraction parameters including the concentration of salt and base in sample matrix, extraction temperature and extraction time were investigated and optimized. Combined with gas chromatography/mass spectrometry (GC/MS) working in selected ion monitoring (SIM) mode, the new method showed good linearity in the range of 20-1500 microg L(-1), good repeatability (RSD<7.5% for MAP, and <11.5% for AP, n=6), and low detection limits (0.1 microg L(-1) for MAP and 0.5 microg L(-1) for AP). Feasibility of the method was evaluated by analyzing human urine samples. Although IL-based SPME is still at the beginning of its development stage, the results obtained by this work showed that it is a promising simple, fast and sensitive sample preparation method.
He
Yi
Y
Department of Sciences, John Jay College of Criminal Justice, The City University of New York, 445 West 59th Street, New York, NY 10019, USA. yhe@jjay.cuny.edu
Pohl
Jeremy
J
Engel
Robert
R
Rothman
Leah
L
Thomas
Marie
M
D000661:Amphetamine / Q000652:urine*; D005554:Forensic Medicine / Q000379:methods*; D006801:Humans; D052578:Ionic Liquids / Q000737:chemistry*; D008694:Methamphetamine / Q000652:urine*; D012680:Sensitivity and Specificity; D052617:Solid Phase Microextraction / Q000379:methods*
D052578:Ionic Liquids; D008694:Methamphetamine; D000661:Amphetamine