Page 119 - Advances in Forensic Applications of Mass Spectrometry - Jehuda Yinon

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preparation is more effective due to similar chemical features of the com-
pounds involved.

2.6.1 Group Screening for Pharmacologically Related Substances
188
Finnish authors described an automated LC/ESI/MS/MS screening/confir-
mation method for 16 beta-blocking agents in urine samples. The drugs were
+
tentatively identified on the base of retention time and (M + H) value. For
confirmation, any qualified compounds were automatically subjected to frag-
mentation. The product ions were compared with the library data. The limits
of identification ranged from 0.02 to 1.2 mg/l.
The same group developed a LC/ESI/MS/MS procedure for screening
189
and quantitation of 18 antihistamine drugs in blood. Since the drugs
belong to acidic and basic compounds, two solvent extractions were per-
formed at pH 3 and 11, and the extracts were combined. The chromatography
was done in 5 min in an acetonitrile–ammonium acetate gradient. For pre-
liminary identification, protonated quasi-molecular ion, the most intensive
fragment, and retention time of each peak were used. The confirmation was
done in second run, using the whole product ion spectrum. The limits of
identification for each drug were below the lowest therapeutic concentration.
Rittner et al. established a library of mass spectra of 70 various psy-
190
choactive drugs and metabolites with LC-ESI-MS. In the preliminary study,
the efficiency of various solid-phase extraction methods and various HPLC
columns was tested. The best results were obtained with C18 SPE cartridges
and C18 columns. Chromatographic separation was performed in
ACN–water–methanol–formic acid gradient. Mass spectra of drugs were
recorded at two levels of fragmentation energy in full scan mode (m/z 100
to 650, positive ions). For many drugs, sodium, potassium, and ACN adducts
were observed. The usefulness of the screening procedure was checked on
140 serum samples taken from road traffic offenders. In 9.8% of the cases
various drugs, mostly benzodiazepines, were detected.
Thieme et al. established a method for screening and quantitation of
191
32 diuretic compounds and their metabolites in urine. The method was
developed for doping control and was based on LC/ESI/MS/MS. The drugs
were extracted from urine using XAD columns and separated on C8 columns
in gradient of ACN–ammonium acetate. The library of mass spectra was
developed using positive or negative ionization and optimized fragmentation
conditions for particular compounds. Since diuretics may belong to acidic
and basic drugs, the authors recommended two subsequent chromatographic
runs (in positive and negative mode) in the screening procedure. This was
superior to the polarity switching in one run.
192
Lacassie et al. published a procedure for the determination of 61 pes-
ticides of various classes (organophosphates, carbamates, organochlorines,

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