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Published:
Journal of Analytical Toxicology,
ISSN 0146-4760,
Volume 24,
Number 4, May/June 2000, pp. 257-265
Simple
and Rapid Determination of Amphetamine, Methamphetamine, and Their Methylenedioxy
Derivatives in Urine by Automated In-Tube Solid-Phase Microextraction Coupled
with Liquid Chromatography–Electrospray Ionization Mass Spectrometry A
simple and rapid method for the determination of amphetamine, methamphetamine,
and their 3,4-methylenedioxy derivatives in urine samples was developed using
automated in-tube solid-phase microextraction (SPME) coupled with liquid chromatography–electrospray
ionization mass spectrometry (LC–ESI-MS). In-tube SPME is an extraction
technique for organic compounds in aqueous samples in which analytes are extracted
from the sample directly into an open tubular capillary by repeated draw/eject
cycles of sample solution. LC–MS analyses of stimulants were initially
performed by liquid injection onto an LC column to determine spectra. Five stimulants
tested in this study gave very simple ESI mass spectra, and strong signals corresponding
to [M+H]+ were observed for all stimulants. The stimulants were well separated
with a Supelcosil LC–CN column using acetonitrile/50mM ammonium acetate
(15:85) as a mobile phase. In order to optimize the extraction of stimulants,
several in-tube SPME parameters were examined. The optimum extraction conditions
were 15 draw/eject cycles of 35 µL of sample in 50mM Tris-HCl (pH 8.5)
at a flow rate of 100 µL/min using an Omegawax 250 capillary column. The
stimulants extracted by the capillary were easily desorbed by mobile phase flow,
and carryover of stimulants was not observed. Using in-tube SPME–LC–ESI-MS
with selected ion monitoring, the calibration curves of stimulants were linear
in the range from 2 to 100 ng/mL with correlation coefficients above 0.9985
(n = 18) and detection limits (S/N = 3) of 0.38–0.82 ng/mL. This method
was successfully applied to the analysis of human urine samples without interference
peaks. The recoveries of stimulants spiked into urine samples were above 81%.Hiroyuki
Kataoka, Heather L. Lord, and Janusz Pawliszyn*
Department of Chemistry, University of Waterloo, Waterloo, Ontario, N2L 3G1, Canada Reproduction
of editorial content of this journal is prohibited without publisher’s
permission.
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