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Novel reductive-reductive mode electrochemical detection of Rohypnol following liquid chromatography and its determination in coffee

Honeychurch, Kevin C.; Davidson, Gwen M.; Brown, Emma; Hart, John P.

Novel reductive-reductive mode electrochemical detection of Rohypnol following liquid chromatography and its determination in coffee Thumbnail


Authors

Gwen M. Davidson

Emma Brown



Abstract

© 2014 Elsevier B.V. Rohypnol (flunitrazepam) has been successfully determined in coffee by high performance liquid chromatography dual electrode detection (LC-DED) in the dual reductive mode. Initial studies were performed to optimise the chromatographic conditions and these were found to be 50% acetonitrile, 50% 50mM pH 2.0 phosphate buffer at a flow rate of 0.75mLmin-1, employing a Hypersil C18, 5μm, 250mm×4.6mm column. Cyclic voltammetric studies were made to ascertain the redox behaviour of Rohypnol at a glassy carbon electrode over the pH range 2-12. Hydrodynamic voltammetry was used to optimise the applied potential at the generator and detector cells; these were identified to be -2.4V and +0.8V for the redox mode and -2.4V and -0.1V for the dual reductive mode respectively. A linear range of 0.5-100μgmL-1, with a detection limit of 20ngmL-1 was obtained for the dual reductive mode. Further studies were then performed to identify the optimum conditions required for the LC-DED determination of Rohypnol in beverage samples. A convenient and rapid method for the determination of Rohypnol in beverage samples was developed using a simple sample pre-treatment procedure. A recovery of 95.5% was achieved for a sample of white coffee fortified at 9.6μgmL-1 Rohypnol.

Citation

Honeychurch, K. C., Davidson, G. M., Brown, E., & Hart, J. P. (2015). Novel reductive-reductive mode electrochemical detection of Rohypnol following liquid chromatography and its determination in coffee. Analytica Chimica Acta, 853, 222-227. https://doi.org/10.1016/j.aca.2014.09.033

Journal Article Type Article
Acceptance Date Sep 19, 2014
Online Publication Date Sep 22, 2014
Publication Date Jan 1, 2015
Deposit Date Dec 8, 2014
Publicly Available Date Mar 2, 2016
Journal Analytica Chimica Acta
Print ISSN 0003-2670
Electronic ISSN 1873-4324
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 853
Pages 222-227
DOI https://doi.org/10.1016/j.aca.2014.09.033
Keywords liquid chromatography dual electrode detection, drug facilitated assault, cyclic voltammetry, beverages, Rohypnol
Public URL https://uwe-repository.worktribe.com/output/839714
Publisher URL http://dx.doi.org/10.1016/j.aca.2014.09.033
Additional Information Additional Information : Published in the journal Analytica Chimica Acta: http://www.sciencedirect.com/science/journal/00032670