SOFT 2004 Meeting Abstracts - Society of Forensic Toxicologists

M41
GAS CHROMATOGRAPHY:'HIGH-RESOLUTION MASS SPECTROMETRIC METHOD FOR
DETERMINING METHAMPHETAMINE AND ITS MAJOR METABOLITE AMPHETAMINE
IN HUMAN HAIR
Jin Young Kim* and Moon Kyo In, Drug Analysis Laboratory, Forensic Science Division, Supreme Public
Prosecutors' Office, Seoul 137-730, Korea
Objective: The purpose of this study is I) to effectively eliminate the biological background or interference
by cosmetic treatment and 2) to develop a suitable confirmatory procedure for analyzing methamphetamine
(MA) and amphetamine (AMP) in human hair using a gas chromatography high-resolution mass
spectrometric (GC-HRMS) technique.
Nature ofthe study: GC-HRMS method development for detecting MA and its metabolite AMP containing
an extremely low concentration in human hair, and eliminating co-eluted compounds in cosmetically
treated hair samples.
Material and methods: We measured the total length of hair samples, and noted special features such as
coloring, bleaching, etc. Before we analyzed hair samples, we 1) washed them twice with 10 mL water and
10 mL acetone, 2) then dried them under a fume hood, 3) finely cut the hair with scissors into small
fragments below 1 mm, and 4) weighed each hair sample. We then transferred thirty milligrams of hair to a
Teflon-faced, rubber-lined screw-cap test tube (16 x 100 mm). To extract analytes from the specimens, we
added 2 mL of methanol-5 M hydrochloric acid (20:1, vlv) containing 100 ng of AMP-ds and MA-ds as
internal standards into test tubes. Then, we directly extracted the hair samples under ultrasonication for lh
and left them to stand at room temperature overnight. The hair was filtered off and filtrate was evaporated
under a nitrogen stream in a TurboVap LV evaporator (Zymark Corp., USA). We dissolved the dried
sample in 50 ilL of trifluoroacetic anhydride (TFAA) and 50 ilL of ethyl acetate and placed it in a dry /~,
heating block for the derivatization at 70°C for 30 min. The mixture was allowed to cool to room
temperature. The residue was reconstituted with 40 ilL volume of ethyl acetate. We injected an aliquot (1
ilL) of the sample solution into GC-MS.
Results: With the HRMS method the limits of detection (LOD) were 9 pglmg for MA and 21 pg/mg for
AMP using a 30 mg hair sample, and the SIM responses were linear with coefficients of correlation
ranging from 0.9998 to 0.9999. The recoveries were found to be 91.1-92.3%. By using HRMS (resolution
of 5000), we improved the detection sensitivity due to eliminating the biological background. The LODs
for MA and AMP were 2.4-4.4 times lower than low-resolution mass spectrometry (LRMS). We applied
the described method to hair samples from suspected MA abusers. In nineteen of the thirty hair samples
not detected by the LRMS SIM technique, we confirmed AMP using an accurate HRMS SIM measurement
of diagnostic ions. In cases where there is a low concentration of AMP in the hair, high resolution SIM is
useful to eliminate chemical background, which is present in single-quadrupole LRMS due to solvent
and/or matrix ionization. The HRMS technique makes the detection of rather low concentrations of drugs
in hair samples possible. In this experiment, the hair samples analyzed using GC-HRMS are not specially
prepared and are the same as those analyzed by GC-LRMS.
Conclusion: The proposed GC-HRMS method shows a high sensitivity and specificity. This method can
also be used as a suitable analytical tool for identirying AMP as major metabolite of MA in human hair,
where identirying metabolites at a low amount in hair samples is requested, and especially in cosmetically
treated hair.
Keywords: Hair, GC-HRMS, Methamphetamine, Amphetamine
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