Forensic electrochemistry: the electroanalytical sensing of Rohypnol® (flunitrazepam) using screen-printed graphite electrodes without recourse for electrode or sample pre-treatment

Abstract

The electroanalytical sensing of Rohypnol® (flunitrazepam) is reported for the first time utilising screen-printed graphite electrodes without the requirement for any additional pre-treatment or modification. The methodology is shown to be useful for quantifying low levels (μg mL(-1)) of Rohypnol® in not only buffered solutions but also two internationally favoured drinks: Coca Cola™ and the alcopop WKD™ without any sample pre-treatment. The current analytical approaches for the sensing of Rohypnol® are also summarised within this paper. The niche of this electroanalytical protocol is the lack of the requirement of any pre-treatment of the sample/beverage or electrode modification (cleaning, pre-treatment etc.) for the determination of Rohypnol® in beverages and offers a potential rapid, cost-effective, yet suitably sensitive and accurate screening solution to the problem posed by coloured drinks to products such as the colour changing 'Smart Cup'.

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

“…We were partially interested in investigating this type of beverage, containing a large portion of possible interferences such as fats and phenolic compounds as many other beverages can be readily assayed by simply diluting the sample with mobile phase or supporting electrolyte [17]. Figure 4 shows the LC-DED chromatograms for extracts of coffee spiked with 9.6 µg/ml (i) and (ii) for unspiked coffee (iii).…”

“…A number of methods have been developed, such as immunoassay [9], GC/MS [10] and HPLC [11,12]. However, there are relatively few reports on the determination of benzodiazepines in beverage samples [13][14][15][16][17][18]. One powerful technique, which has received little attention for the determination of benzodiazepines, is high performance liquid chromatography with dual electrode detection (LC-DED).…”

The Mediatorless Electroanalytical Sensing of Sulfide Utilizing Unmodified Graphitic Electrode Materials

“…Screen-printing technology permits the mass production of highly reproducible electrode configurations and, due to its scales of economy, inexpensive electrochemical sensing platforms can be readily fabricated [19][20][21].…”

Pharmaceutical electrochemistry: The electrochemical detection of aspirin utilising screen printed graphene electrodes as sensors platforms

“…In contrast, suggesting of electrochemical sensors is an attractive alternative method for electroactive species detection, because of its inherent advantages of simplicity, high sensitivity and relatively low cost [10].…”

“…The utilisation of screen-printed electrodes as sensors platforms have attracted great interest since they provide a low cost, single-shot disposable yet highly reproducible and reliable electrochemical measurement of the target analyte [10].…”