Determination of Methamphetamine and Amphetamine in Urine by Headspace Gas Chromatography/Mass Spectrometry

Abstract

The sensitivity of combined headspace gas chromatography (HSGC) and mass spectrometry (MS) for a stimulant (methamphetamine) and its urinary metabolite (amphetamine) was investigated. The analytical methods consisted of a combination of (1) HSGC and electron impact (EI)-MS, (2) HSGC, on-column trifluoroacetyl (TFA) derivatization of stimulants and El-MS and (3) HSGC and chemical ionization (CI)-MS using isobutane as a reagent gas. The combination of HSGC and El-MS after on-line TFA-derivatization of stimulants (2) was the most informative method in these three procedure, but HSGC/ CI-MS (3) was the most sensitive method. Detection limits of methamphetamine (MA) and amphetamine (AP) in urine by HSGC/ CI-MS were found to be about 10 ng/ ml (S/ 1V>l0) by monitoring quasimolecular ions of these compounds; m/z 150 and 136 observed on their mass spectra, respectively. Furthermore, the most sensitive CI-MS method was applied to quantivative analysis of these drugs excreted in urine by the selected ion monitoring (HSGC/ CI-SIM).

Development of a two-step injector for GC–MS with on-column derivatization, and its application to the determination of amphetamine-type stimulants (ATS) in biological specimens

“…To cope with a large number of samples, we have used MBTFA as an on-column derivatization reagent, which allows the injection of an easy-to-prepare free-base ATS extract, and its instant trifluoroacetylation, without any tedious manual handling [7,8]. This derivatization method, especially in combination with the headspace technique, provides significant time savings in the GC-MS determination of ATS in urine [7,9]. Although no paper has described the use of MBTFA for the on-column derivatization of drugs in hair, Hidvegi et al [10] recently reported its use for the on-column derivatization of ATS in serum.…”

3,4-Methylenedioxyamphetamines

“…In the SIM mode, the ions at m/z 180, 194 and 208 should be selected for MDA, MDMA and MDEA, respectively. e) For the TFA-derivatization, N-methylbis(trifl uoroacetamide) (MBTFA) is also applicable as an on-column derivatization reagent [23,24]; MBTFA is injected immediately aft er the sample injection. Upon applying to a high concentration of a sample, a part of the injected analytes, however, may be underivatized.…”