Novel electrode reactions of diazepam, flunitrazepam and lorazepam and their exploitation in a new redox mode LC-DED assay for serum

Honeychurch, Kevin C.; Chong, Ai Teng; Elamin, Khalil; Hart, John P.

Abstract

Previously unreported voltammetric redox behaviour was identified for flunitrazepam, lorazepam and diazepam at a glassy carbon electrode. This was successfully exploited for their determination in serum by high performance liquid chromatography dual electrode detection in the redox mode (LC-DED). Initial studies were performed to optimise the chromatographic conditions and these were found to be 50% acetone, 50% 100 mM pH 2 phosphate buffer at a flow rate of 0.8 ml min -1, employing a Hypersil C 18, 5 μm, 250 mm × 4.6 mm column held at 40 °C. Cyclic voltammetric studies were made to ascertain the redox behaviour of these benzodiazepines over the pH range 2-10. Hydrodynamic voltammetry was used to optimise the applied potential at the amperometric generator and detector cells; these were identified to be -2.45 V (vs. stainless steel) and +1.0 V. (vs. Ag/AgCl). © 2012 The Royal Society of Chemistry.

• Journal Article Type: Article
• Publication Date: Jan 1, 2012
• Journal: Analytical Methods
• Print ISSN: 1759-9660
• Electronic ISSN: 1759-9679
• Publisher: Royal Society of Chemistry
• Peer Reviewed: Peer Reviewed
• Volume: 4
• Issue: 1
• Pages: 132-140
• DOI: https://doi.org/10.1039/c1ay05419h
• Keywords: liquid chromatography, electrochemical detection, diazepam, flunitrazepam and lorazepam
• Public URL: https://uwe-repository.worktribe.com/output/953521
• Publisher URL: http://dx.doi.org/10.1039/C1AY05419H