Use of direct-probe mass spectrometry as a toxicology confirmation method for demoxepam in urine following high-performance liquid chromatography

• Published in: Journal of chromatography. B, Biomedical applications Vol. 683; no. 2; pp. 199 - 208
• Main Authors: Essien, Herbert, Jason Lai, S., Binder, Steven R., King, David L.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 30-08-1996; Elsevier
• Subjects: Anti-Anxiety Agents - chemistry; Anti-Anxiety Agents - urine; Benzodiazepines; Benzodiazepinones - chemistry; Benzodiazepinones - urine; Biological and medical sciences; Biotransformation; Chlordiazepoxide - analysis; Chlordiazepoxide - chemistry; Chromatography, High Pressure Liquid; Demoxepam; Gas Chromatography-Mass Spectrometry; Humans; Immunoassay; Mass Spectrometry - methods; Medical sciences; Neuropharmacology; Pharmacology. Drug treatments; Psycholeptics: tranquillizer, neuroleptic; Psychology. Psychoanalysis. Psychiatry; Psychopharmacology; Demoxepam; Human; Urine; Metabolite; HPLC chromatography; Benzodiazepine derivatives; Mass spectrometry; Quantitative analysis
• ISSN: 0378-4347; 1572-6495
• DOI: 10.1016/0378-4347(96)00119-3

The identification of the metabolite demoxepam in human urine establishes that chlordiazepoxide, a common benzodiazepine, has been administered. Like N-oxide metabolites of other drugs, demoxepam cannot be detected by gas chromatography—mass spectrometry (GC-MS), due to thermal decomposition, and the product, nordiazepam, is a metabolite common to many benzodiazepines. Demoxepam can be readily screened using a high-performance liquid chromatography (HPLC) system such as REMEDi HS; at 35°C, no thermal decomposition will occur. Currently, there is no confirmation method available for the detection of demoxepam in urine samples. In this study, we demonstrated that following collection of the HPLC fraction, demoxepam can be confirmed using the technique of direct-probe MS. The mass spectra of demoxepam and nordiazepam differ and are easily distinguishable from each other. Ten urine samples that were analyzed by HPLC and determined to contain demoxepam were evaluated; demoxepam was confirmed in each case by direct-probe MS.