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Published:
Journal of Analytical Toxicology,
ISSN 0146-4760,
Volume 27, Number 3, April 2003,
pp. 156-161
TECHNICAL NOTE: 1H NMR Spectroscopy and GC–MS Analysis
of a-Chloralose. Application to Two Poisoning Cases
Sandrine Savin[1], Bernard Cartigny[1], Nathalie
Azaroual[2], Luc Humbert[1], Michel Imbenotte[3], Djamel Tsouria[4], Gaston Vermeersch[2],
and Michel
Lhermitte[1],[3]
[1]Laboratoire de Biochimie et Biologie Moléculaire, Hôpital Albert
Calmette, Lille, France;
[2]Laboratoire de Physique, UPRESA CNRS 8009, Laboratoire
d’Application RMN de l’Université de Lille 2, Lille, France;
[3]Laboratoire de Toxicologie, Faculté des Sciences Pharmaceutiques et
Biologiques,
Lille, France; and
[4]Service de Réanimation Médicale, Hôpital
Provo, Roubaix, France
a-Chloralose, a compound
widely used as a rodenticide and in the control of bird pests, is readily
available. Two cases of intentional
poisoning are reported. Both patients became comatose and presented hypersialorrhea
and myoclonal crises in the legs. They were discharged from hospital after
several days. As clinical signs of a-chloralose poisoning lack specificity,
anamnesis might be difficult, particularly in the case of delayed diagnosis.
Toxicological analysis is therefore critical, and this article reports the
investigation of serum and urine samples by gas chromatography–mass
spectrometry (GC–MS) in the electron-impact mode, and by 1H nuclear
magnetic resonance (1H NMR) spectroscopy. Non-hydrolyzed urinary samples
and those hydrolyzed by b-glucuronidase were taken into consideration. After
acetylation, GC–MS analysis was based on characteristic mass-to-charge
ratio values of 272 for a-chloralose and 206 for b-hydroxyethyltheophylline,
which was used as internal standard. Characterization of a-chloralose species
by 1H NMR spectroscopy was performed taking two parameters into account:
chemical shift and coupling-constant values. Without any pretreatment, 1H
NMR spectroscopy revealed the presence of free (5.50 and 6.15 ppm) and conjugated
forms of a-chloralose by characteristic resonances of H1 and chloral-type
protons, respectively. Quantitative analysis was performed by relative integration
of peak areas. Serum a-chloralose showed concentrations below the quantitation
limit of both methods. In urine samples, the free chemical species rapidly
decreased. GC–MS analysis revealed the predominence of conjugation
after a b-glucuronidase hydrolysis step. 1H NMR analysis directly showed
that on admission of the first patient, average urinary concentrations were
1.73 mmol/L (535 mg/L) for the free form and 13.72 and 6.25 mmol/L for the
two conjugated forms. A later enzymatic treatment confirmed the total concentration
of a-chloralose chemical species. Analysis of a-chloralose in urine by either
GC–MS or 1H NMR spectroscopy methods proved to be comparable. Reproduction
of editorial content of this journal is prohibited without publisher’s
permission.
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