Page 100 - Advances in Forensic Applications of Mass Spectrometry - Jehuda Yinon

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compounds. In biological extracts, the limit of detection was 10 to 40 times
lower for a quadrupole instrument than for an ion trap.
Breindahl and Andreasen applied ESI/LC/MS for determination of THC-
99
COOH in urine. Urine was subjected to basic hydrolysis and solid phase
extraction. THC-COOH and its deuterated analog were analyzed with
HPLC/ESI/MS, using a C8 reversed-phase column, gradient elution in ace-
tonitrile–formic acid, and SIM detection (positive ions). In-source collision-
induced dissociation was applied and protonated quasi-molecular ion as well
as two fragment ions were monitored. LOD was 15 mg/l. Tai and Welch 100
determined THC-COOH with HPLC/ESI/MS (negative ions). The drug was
extracted from urine with SPE and subjected to isocratic separation on an
ODS column in the methanol–ammonium acetate mobile phase. Only depro-
tonated quasi-molecular ions of the drug and its deuterated analog were
monitored. Weinmann et al. used LC/MS/MS for simultaneous determina-
101
tion of THC-COOH and its glucuronide in urine. In this method, the
cleavage of conjugates was omitted. THC-COOH and its glucuronide were
extracted from urine with ethyl acetate–ether (1:1) and separated on C8
column in a gradient of ammonium formate buffer and acetonitrile.
ESI/MS/MS was used for detection using protonated quasi-molecular ions
as precursor ions and two fragment ions for each drug as product ions. The
specificity of the method was checked using enzymatic hydrolysis of THC-
COOH-glucuronide.
In another study, Weinmann et al. developed a fast method for deter-
102
mination of THC-COOH in urine using automated solid phase extraction
after alkaline hydrolysis. HPLC was done in gradient elution on a short ODS
column. THC-COOH was detected with APCI/MS/MS in a negative ioniza-
tion mode. Three product ions, originating from deprotonated quasi-molec-
ular ion, were used for identification and quantitation. The LOD was 2.0 mg/l
and LOQ was 5.1 mg/l.

2.3.5 Hallucinogens
2.3.5.1 LSD
LSD (lysergic acid diethylamide) is an extremely potent hallucinogenic drug.
Its single dose (“trip”) ranges from 30 to 100 mg. The drug is rapidly and
extensively metabolized, and only a very small fraction is excreted unchanged
with urine. In the first phase of application of LC/MS for the analysis of
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LSD, this drug and its demethylated metabolite was determined in urine.
Webb et al. developed an immunoaffinity extraction of LSD from urine
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followed by LC/ESI/MS. Methysergide was used as internal standard for quan-
titation. Protonated molecular ion and two fragments were monitored; the
LOD was 0.5 mg/l at 5 ml urine volume. In the next study of the same group,
methysergide was replaced by a triple deuterated LSD analog used as internal
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