Electroanalytical Sensing of Flunitrazepam Based on Screen Printed Graphene Electrodes

Enriqueta Garcia-Gutierrez,Carlos Lledo-Fernandez

doi:10.3390/chemosensors1030068

Abstract

We present a new electrochemical sensor for Flunitrazepam using disposable and economic Screen Printed Graphene Electrodes. It was found that the electrochemical response of this sensor was improved compared to Screen Printed Graphite Electrodes and displayed an excellent analytical performance for the detection of Flunitrazepam. Those characteristics could be attributed to the high Flunitrazepam loading capacity on the electrode surface and the outstanding electric conductivity of graphene. The methodology is shown to be useful for quantifying low levels of Flunitrazepam in a buffer solution. The protocol is also shown to be applicable for the sensing of Flunitrazepam in an alcoholic beverage e.g., Gordon’s Gin & Tonic.

Highlights

Benzodiazepines such as Flunitrazepam have been receiving more attention in relation to their illicit use in assaults and robberies; [1,2,3]
Flunitrazepam is an anxiolytic and hypnotic drug know better under the name “Rohypnol” which is normally administered as a short term treatment for sleeping disorders such as insomnia [4]
The sedative effect of the drug is increased by alcohol consumption which creates psychomotor impairment and causes the victim to suffer from a “blackout”, a type of a short term amnesia that prevents the victim from recalling much, if any, of the attack

Summary

Introduction

Benzodiazepines such as Flunitrazepam have been receiving more attention in relation to their illicit use in assaults and robberies; [1,2,3]. McGuire et al [19] reported the detection of nitrazepam utilising screen printed graphite electrodes (SPGEs) in beverages by adsorptive stripping voltammetry. The drawbacks to these methods are that the times for the analysis are longer than 6 min per sample and a liquid/liquid extraction prior to analysis is needed. Lledo-Fernandez et al [20,21] investigated the behavior and detection of Flunitrazepam in buffer and beverages using SPGE Those methods were not as sensitive as the method described in this manuscript. SPGrE exhibited better electrochemical performance with good stability, high selectivity and reproducibility. With a detection limit of 6 ng/mL (based on 3-sigma) This method exhibited better electrochemical performance with good stability, high selectivity and reproducibility. The applicability of SPGrE was demonstrated through determining Flunitrazepam in real samples

Experimental Section

Optimization of the Electrochemical Protocol

Electroanalytical Applications of ECL in an Alcoholic Beverage

Conclusions