Universität zu Köln

Lopez-Avila, Viorica, Cooley, James, Urdahl, Randall and Thevis, Mario (2012). Determination of stimulants using gas chromatography/high-resolution time-of-flight mass spectrometry and a soft ionization source. Rapid Commun. Mass Spectrom., 26 (23). S. 2714 - 2725. HOBOKEN: WILEY. ISSN 1097-0231

Full text not available from this repository.

Abstract

RATIONALE The aim of this study was to investigate the mass spectral fragmentation of a small set of stimulants in a high-resolution time-of-flight mass spectrometer equipped with a soft ionization source using vacuum ultraviolet (VUV) photons emitted from different plasma gases. It was postulated that the use of a plasma gas such as Xe, which emits photons at a lower energy than Kr or Ar, would lead to softer ionization of the test compounds, and thus to less fragmentation. METHODS A set of nine stimulants: cocaine, codeine, nicotine, methadone, phenmetrazine, pentylenetetrazole, niketamide, fencamfamine, and caffeine, was analyzed by gas chromatography/time-of-flight mass spectrometry (GC/TOFMS) in positive ion mode with this soft ionization source, using either Xe, Kr, or Ar as plasma gases. Working solutions of the test compounds at 0.1 to 100 ng/mu L were used to establish instrument sensitivity and linearity. RESULTS All test compounds, except methadone and pentylenetetrazole, exhibited strong molecular ions and no fragmentation with Xe-microplasma photoionization (MPPI). Methadone exhibited significant fragmentation not only with Xe, but also with Kr and Ar, and pentylenetetrazole could not be ionized with Xe, probably because its ionization energy is above 8.44 eV. The Kr- and Ar-MPPI mass spectra of the test compounds showed that the relative intensity of the molecular ion decreased as the photon energy increased. CONCLUSIONS When coupled to a TOF mass spectrometer this soft ionization source has demonstrated signal-to-noise (S/N) ratios from 7 to 730 at 100 pg per injection (depending on the compound), and a dynamic range of three orders of magnitude (100 pg to 100 ng) for some of the test compounds. Copyright (C) 2012 John Wiley & Sons, Ltd.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Lopez-Avila, Viorica UNSPECIFIED UNSPECIFIED UNSPECIFIED Cooley, James UNSPECIFIED UNSPECIFIED UNSPECIFIED Urdahl, Randall UNSPECIFIED UNSPECIFIED UNSPECIFIED Thevis, Mario UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-476664
DOI:	10.1002/rcm.6398
Journal or Publication Title:	Rapid Commun. Mass Spectrom.
Volume:	26
Number:	23
Page Range:	S. 2714 - 2725
Date:	2012
Publisher:	WILEY
Place of Publication:	HOBOKEN
ISSN:	1097-0231
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language SPECTRA Multiple languages Biochemical Research Methods; Chemistry, Analytical; Spectroscopy Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/47666