Page 16 - Advances in Forensic Applications of Mass Spectrometry - Jehuda Yinon

1522_C01.fm Page 3 Tuesday, December 2, 2003 10:05 AM

are necessary that allow the simultaneous detection of as many toxicants in
biosamples as possible. As already mentioned, GC/MS procedures are most
often used today. HPLC coupled to diode array detectors (DAD) 33–39 have
also been described for general screening purposes, but the specificity is lower
40
than that of full-scan EI MS. Valli et al. combined GC/MS blood screening
26
with urine REMEDi testing and Saint-Marcoux et al. combined GC/MS,
HLPC-DAD, and LC/MS. LC/MS procedures in this field were several times
41
42
reviewed in the last years, e.g., by Maurer, Van Bocxlaer et al., Marquet, 28
and Bogusz. 31,43
Most of the STA procedures cover basic (and neutral) drugs, which
include the majority of toxicants. For example, most of the psychotropic
drugs have basic properties like neurotransmitters. Nevertheless, some classes
of acidic drugs or drugs producing acidic metabolites, like cardiovascular
drugs such as angiotensin converting enzyme (ACE) inhibitors and angio-
tensin II AT receptor blockers, dihydropyridine-type calcium channel block-
1
ers (metabolites), diuretics, coumarin anticoagulants, antidiabetics of the
sulfonylurea type, barbiturates, or nonsteroidal antiinflammatory drugs
(NSAIDs), are relevant to clinical and forensic toxicology or doping. There-
fore, GC/MS screening procedures are described here not only for detection
of basic and neutral, but also acidic drugs in biosamples. After the unequiv-
ocal identification, reliable quantification of the drugs can also be performed
by GC/MS, especially if stable isotopes are used as internal standards (for
example, see References 44, 45), or in case of rather polar or unstable com-
pounds, by LC/MS, even using universal internal standards like deuterated
trimipramine. 22,24,25,46 However, whatever technique is used, quantification
procedures must be validated according to international guidelines, which
have recently been reviewed by Peters and Maurer. 47

1.1.1 Matrices for Drug Screening
Blood (plasma, serum) is the sample of choice for quantification. However,
if the blood concentration is high enough, screening can also be performed
herein. This is especially advantageous if only blood samples are available
and/or the procedures allow simultaneous screening and quantifica-
tion. 6,9,32,48,49 In driving under the influence of drugs (DUID) cases, blood
analysis is even mandatory. A GC/MS screening procedure has been
described for about 100 acid, neutral, and basic drugs in horse plasma. 50
Methods for postmortem drug analysis have been reviewed recently. 51
GC/MS analysis of drugs in alternative matrices like hair, 8,19,52 sweat and
saliva, 7,19 meconium, or nails have also been described, but a comprehen-
54
53
sive screening for a series of various drugs has not yet been described in
alternative matrices, probably because the concentrations are too low for

© 2004 by CRC Press LLC