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Hair analysis for illicit drugs by using capillary zone electrophoresis-electrospray ionization-ion trap mass spectrometry
In forensic toxicology, hair analysis has become a well established analytical strategy to investigate retrospectively drug abuse histories. In this field, gas chromatography–mass spectrometry and high-performance liquid chromatography–mass spectrometry are currently used, often after preliminary sc...
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Published in: | Journal of Chromatography A 2007-08, Vol.1159 (1), p.185-189 |
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Main Authors: | , , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | In forensic toxicology, hair analysis has become a well established analytical strategy to investigate retrospectively drug abuse histories. In this field, gas chromatography–mass spectrometry and high-performance liquid chromatography–mass spectrometry are currently used, often after preliminary screening with immunoassays. However, on the basis of previous applications to pharmaceutical analysis, capillary zone electrophoresis coupled to ion trap mass spectrometry looks also highly promising. The purpose of the present work was the development of a simple and rapid CZE–MS method for sensitive and quantitative determination of the main drugs of abuse and their metabolites (namely, 6-monoacetylmorphine, morphine, amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethampthetamine (MDMA), benzoylecgonine, ephedrine and cocaine) in human hair. Hair samples (100
mg) were washed, cut and incubated overnight in 0.1
M HCl at 45
°C, then neutralized with NaOH and extracted by a liquid–liquid extraction method. CZE separations were carried out in a 100
cm
×
75
μm (I.D.) uncoated fused silica capillary. The separation buffer was composed of 25
mM ammonium formate, pH 9.5; the separation voltage was 15
kV. Electrokinetic injections were performed at 7
kV for 30
s under field amplified sample stacking conditions. ESI-ion trap MS detection was performed in the ESI positive ionization mode using the following conditions: capillary voltage 4
kV, nebulizer gas (nitrogen) pressure 3
psi, source temperature 150
°C and drying gas (nitrogen) flow rate 8
l/min. A sheath liquid, composed of isopropanol–water (50:50, v/v) with 0.5% formic acid, was delivered at a flow rate of 4
μl/min. The ion trap MS operated in a selected ion monitoring mode (SIM) of positive molecular ions for each drug/metabolite. Collision induced fragmentation was also possible. Nalorphine was used as internal standard. Under the described conditions, the separation of all compounds, except amphetamine/methamphetamine, MDA/MDMA and morphine/6-MAM was achieved in 20
min, with limits of detection lower than the most severe cut-offs adopted in hair analysis (i.e. 0.1
ng/mg). Linearity was assessed within drug concentration ranges from 0.025 to 5
ng of each analyte/mg of hair. Analytical precision was fairly acceptable with RSD's ≤3.06% for migration times and ≤22.47% for areas in real samples, in both intra-day and day-to-day experiments. On these grounds, the described meth |
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ISSN: | 0021-9673 |
DOI: | 10.1016/j.chroma.2007.01.011 |