Abstract
This paper describes the application of solid-phase microextraction
(SPME) with subsequent injection in a gas chromatograph–mass
spectrometer (GC–MS) (electron impact, full scan) for the
screening analysis of stimulants and narcotics in urine. Several
d i fferent kinds of fibers were preliminarily tested and
comparatively evaluated considering the influence on the overall
analytical performance of the method; other experimental
parameters; and, primarily among them, the volume of urine, the
pH value, and the time of adsorbtion. The optimal experimental
conditions have been recorded using 0.5 mL of urine with the pH
value adjusted to 10 with carbonate buffer, and in which is
immersed a polydimethylsiloxane/divinylbenzene fiber, with a
sampling time of 30 min; the fiber is then directly desorbed in the
injection port of the GC–MS equipment. All the analytes show a
good linearity (R2 > 0.99 for most substances) and a good
reproducibility at the concentration corresponding to the minimum
performance requirement limit or at the cut-off value fixed by the
World AntiDoping Agency (CV% < 11). The limit of detection of
the method is 50 ng/mL for the majority of the substances
investigated. Imidazole-based drugs (e.g., naphazoline) and local
anesthetics can also be included in this screening method.
Whenever necessary, confirmation analyses may also be performed
by following the same pre-chromatographic procedure. Integrating
the SPME process and the GC–MS analysis with a dedicated
autosampler that combines the microextraction and injection
capacities maximizes the overall analytical capacity of a single
GC–MS system and reduces the human labor necessary for and the
environmental impact of screening for stimulants and narcotics
excreted free in urine.
Lingua originale | Inglese |
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pagine (da-a) | 217-222 |
Numero di pagine | 6 |
Rivista | Journal of Analytical Toxicology |
Volume | 29 |
Stato di pubblicazione | Pubblicato - 2005 |
Keywords
- SPME, GC/MS
- narcotics
- stimulants
- urine analysis