title: The redox behaviour of diazepam (Valium®) using a disposable screen-printed sensor and its determination in drinks using a novel adsorptive stripping voltammetric assay.
abstract: In this study we investigated the possibility of applying disposable electrochemical screen-printed carbon sensors for the rapid identification and quantitative determination of diazepam in beverages. This was achieved utilising a previously unreported oxidation peak. The origin of this peak was investigated further by cyclic voltammetry and gas chromatography/mass spectroscopy. At pH 6 the voltammetric behaviour of this oxidation process was found to involve adsorption of the drug allowing for the development of an adsorptive stripping voltammetric assay. Experimental conditions were then optimised for the determination of diazepam in a beverage sample using a medium exchange technique. It was shown that no elaborate extraction procedures were required as the calibration plots obtained in the absence and presence of the beverage were very similar.
authors.affiliation: Centre for Research in Biosciences, Faculty of Health and Life Sciences, University of the West of England, Bristol, Frenchay Campus, Coldharbour Lane, Bristol, BS16 1QY, UK.
authors.forename: Kevin C
authors.initials: KC
authors.lastname: Honeychurch
authors.forename: Adrian
authors.initials: A
authors.lastname: Crew
authors.forename: Hannah
authors.initials: H
authors.lastname: Northall
authors.forename: Stuart
authors.initials: S
authors.lastname: Radbourne
authors.forename: Owian
authors.initials: O
authors.lastname: Davies
authors.forename: Sam
authors.initials: S
authors.lastname: Newman
authors.forename: John P
authors.initials: JP
authors.lastname: Hart
mesh_terms: D000327:Adsorption; D000434:Alcoholic Beverages / Q000032:analysis*; D014151:Anti-Anxiety Agents / Q000302:isolation & purification*; D002138:Calibration; D002244:Carbon / Q000737:chemistry; D002253:Carbonated Beverages / Q000032:analysis*; D003975:Diazepam / Q000302:isolation & purification*; D055664:Electrochemical Techniques / Q000592:standards*; D004566:Electrodes; D006801:Humans; D006863:Hydrogen-Ion Concentration; D057230:Limit of Detection; D010084:Oxidation-Reduction
chemical_list: D014151:Anti-Anxiety Agents; D002244:Carbon; D003975:Diazepam
keywords: Beverages; Cyclic voltammetry; Diazepam; Drug screening; Electrochemical sensor; Screen-printed