Sem ttulo de diapositivo

1
Some relevant data regarding the detection
of 1-benzyl-piperazine
Carmo Manzoni (?)1 , Douwe de Boer1, Marta
Calçada1, Irina J. Póvoa1 Carla Martins1, João M.
Franco2, Mário J. Dias2, Lesseps J.A.L. dos
Reys1 1-Laboratório de Análises de Dopagem e
Bioquímica 2-Instituto de Medicina Legal de Lisboa
Laboratório de Análises de Dopagem e Bioquímica
Introduction
Several examples of compounds that contain a
piperazine moiety in their molecule bind to
serotonin receptors. Apparently the structures of
piperazine-like compounds have good interaction
possibilities with these receptors, which can be
understood if orientations of for example
1-aryl-piperazines are compared with that of
serotonin (Figure 1). Although as a group, the
piperazine-like compounds can not be considered
as selective compounds for serotonin receptors,
they may be made more site selective with the
appropriate substituents. An illustration of the
phenomenon of the piperazine-like compounds is
1-benzyl-piperazine, which roughly mimics the
psychoactive effects of the phenylalkylamine
(S)-amphetamine (Figure 1), although at a higher
dosage. 1-Benzyl-piperazine is also of special
interest, because it is being promoted as a
drug-of-abuse on the Internet. It is since
January 2000 commercially available on a European
Internet website as a so-called synthetic
stimulant. It is sold in capsules under the name
of A2 in a dosage of 125 mg of its
dihydrochloride salt. As this development may
have consequences for drug-of abuse and forensic
cases, we studied some relevant analytical
aspects of 1-benzyl-piperazine. Studied were the
cross reactivity in several amphetamine
immunoassays and the potential use of the GC/NPD
screening and GC/MS confirmation analysis.
Figure 2. Cross reactivity between
1-benzyl-piperazine and amphetamine in the
Abuscreen Online assay
Figure 3. GC/NPD analytical conditions and
chromatogram
Figure1. Structure similarities
Experimental
The immunoassays evaluated were the Amphetamines
Abuscreen Online (Roche Diagnostics), the
Enzyme-multiple Immunoassay Technique (EMIT)
d.a.u. Amphetamine assay (Dade Behring
Diagnostics), the AxSYM Fluorescence
Polarization Immunoassay (FPIA)
Amphetamine/Methamphetamine II Immunoassay
(Abbott Diagnostics Systems) and the Amphetamine
MICRO-PLATE Enzyme Immunoassay (EIA) (OraSure
Technologies). GC/NPD analysis was performed
after basic extraction with tert.-butyl methyl
ether at pH 12. GC/MS analysis was performed
after N,O-trifluoroacetylation gt 50 ?L
of trifluoroacetic anhydride 50 ?L of ethyl
acetate gt incubation for 30 min at 65
?C
Figure 4. Mass spectrum and fragments of 1-
benzyl-piperazine
Conclusion
Results
Immunoassay 1-Benzyl-piperazine showed a low
cross reactivity (lt 1) using the Amphetamines
Abuscreen Online assay (Figure 2) and the
EMIT d.a.u. Amphetamine assay. The FPIA
Amphetamine/Methamphetamine II Immunoassay and
the Amphetamine MICRO-PLATE Enzyme Immunoassay
did not show any cross reactivity. GC/NPD
analysis The analysis of 1-benzyl-piperazine
resulted in a good response and peak shape. The
extraction recovery was gt 80 (Figure 3). GC/MS
confirmation The analysis of the N-TFA derivative
of 1-benzyl-piperazine resulted in a
characteristic mass spectrum (Figure 4).
Not every immunoassays showed cross reactivity
for 1- benzyl-piperazine The implementation of
1-benzyl-piperazine in relevant analytical
procedures can easily be achieved using a GC/NPD
analysis. As a confirmation procedure the use of
the N,O-trifluoroacetylation derivatisation step
results in a characteristic mass spectrum
Laboratório de Análises de Dopagem e Bioquímica -
Instituto Nacional do Desporto Centro de Medicina
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