Negative-Ion Chemical Ionization Gas Chromatography–Mass Spectrometry Assay for Enantioselective Measurement of Amphetamines in Oral Fluid: Application to a Controlled Study with MDMA and Driving Under the Influence Cases
Frank T. Peters, Nele Samyn, Thomas Kræmer, Wim J. Riedel, Hans H Maurer
Clinical Chemistry March 2, 2007 DOI: 10.1373/clinchem.2006.081547 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Method validation and application study Peer reviewed |
|---|---|
| Population | Oral fluid samples from a controlled MDMA study and from authentic driving under the influence of drugs cases |
| Topics | MDMA |
| Keywords | Gas chromatography–mass spectrometry Chemical ionization Enantioselective synthesis Selected ion monitoring Analytical chemistry journal Organic chemistry Pharmacology |
| Citations | 36 |
| Key points | The enantioselective GC-NICI-MS assay reliably measures amphetamine, methamphetamine, MDA, and MDMA in oral fluid, but oral fluid data cannot predict plasma concentrations or enantiomer ratios. |
Abstract
Abstract
Background: Enantioselective analysis of amphetamine (AM), methamphetamine (MA), 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA), and 3,4-methylenedioxyethylamphetamine (MDEA) helps interpret toxicological results. Methods have been described for various matrices, but so far not for oral fluid, a matrix of increasing importance in testing for drugs of abuse, especially in the context of driving under the influence of drugs (DUID).
Methods: After dilution with 200 μL carbonate buffer (pH 9), oral fluid samples (10–50 μL) were derivatized with S-heptafluorobutyrylprolyl chloride. The resulting diastereomers were extracted into 100 μL of cyclohexane, separated by gas chromatography (HP-5MS column), and detected by mass spectrometry in the negative-ion chemical ionization mode (GC-NICI-MS). The method was validated and applied to samples from a controlled study with MDMA and from authentic DUID cases.
Results: The derivatized AM, MA, MDA, MDMA, and MDEA enantiomers were well separated from each other. The method was linear from 5–250 μg/L per enantiomer of MDA and from 25–1250 μg/L per enantiomer of AM, MA, MDMA, and MDEA. With the exception of MDEA, analytical recoveries, repeatability, and intermediate precision were within required limits. The analyte concentrations and enantiomer ratios in the application samples correlated only weakly with corresponding published plasma data.
Conclusions: This sensitive, reliable, and fast GC-NICI-MS assay enantioselectively measures AM, MA, MDA, and MDMA in oral fluid samples. Prediction of plasma concentrations and enantiomer ratios from respective oral fluid data is not possible.