Development of a specific detection method for Cl-containing drugs

<p>[Introduction] Chlorine (Cl) is a group 17 element with a specific isotopic pattern (³⁵Cl:³⁷Cl = 76:24), and consists of antihistamines and antidepressants. Unfortunately, these drugs are often used in suicide. In suicide cases, identification of the taken drug or post-mortem metabolites (PMs) is important form forensic toxicology. However, PMs are oftentimes different from pre-mortem metabolites. Thus, the specific detections of Cl-containing drugs and their PMs would be effective to identify a causative drug. In this study, we developed a specific detection method for Cl-containing drugs (Cl isotope pattern screening, Cl-IPS) and detected their PMs transformed via the Fenton reaction by hemoglobin (Hb). [Methods] First, Diazepam (DZP) and Triazolam (TZL) were used as model compounds, respectively. DZP and TZL solutions were analyzed by Cl-IPS with LC-Q-Orbitrap-MS. The artificially prepared blood and urine containing DZP and TZL were extracted, and analyzed by Cl-IPS. DZP and TZL were reacted with Hb, and the reaction mixtures were analyzed by Cl-IPS. Additional 20 Cl-containing drugs were also analyzed by Cl-IPS. [Results and Discussion] DZP and TZL were specifically and quantitatively detected by Cl-IPS, and were also detected in the presence of matrices such as blood and urine. PMs of DZP and TZL were identified by Cl-IPS. Because the additional 20 Cl-containing drugs were also specifically detected by Cl-IPS, Cl-IPS was an effective technique to selectively detect Cl-containing drugs and their PMs. Therefore, Cl-IPS could be of useful in forensic toxicology.</p>