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

© 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

Prospectus, December 6, 2017

WPCD celebrates 40 years of operation; Bad Moms Christmas a passable, sometimes tedious sequel; On Black Friday we stay out all night: a family\u27s tale; Giertz Gallery holds mug and dessert fundraiser; Antique naturalism exhibit at KAM closing soonhttps://spark.parkland.edu/prospectus_2017/1032/thumbnail.jp

Prospectus, November 15, 2017

Dodds Park hosts scholarship fundraiser run; Review: Hansel and Gretel at KCPA; 2017\u27s Pokemon film relives 1998 classic series; Tyler Oakley talks about journey as YouTube LGBTQ activist; Cobra\u27s men\u27s basketball wins against REnd Lake on Nov. 8.https://spark.parkland.edu/prospectus_2017/1030/thumbnail.jp

On Free-Electron Laser Growing Modes and their Bandwidth

Free-electron lasers play an increasing role in science, from generating unique femtosecond X- ray pulses for single short recording of the protein structures to amplifying feeble interactions in advanced cooling systems for high-energy hadron colliders. While modern Free-electron laser codes can describe their amplification mechanism, a deep analytical understanding of the mechanism is of extreme importance for a number of applications. Mode competition, their growth rates and amplification bandwidth are among the most important parameters of a free-electron laser. A dispersion relation, which defines these important characteristics, can be solved analytically only for a very few simple cases. In this letter we show that for a typical bell-shape energy distribution in electron beam there is no more that one growing mode. We also derive an analytical expression which determines the bandwidth of the free-electron laser.Comment: 4 pages, submitted to PR

Prospectus, October 29, 20175

AgEST host annual career, tech education open house; PC astronomy club visits renowned observatory in Wisconsin; Parkland not just for traditional students; Students say thanks to those who\u27ve helped out; PC music ensembles come together for fall concert;https://spark.parkland.edu/prospectus_2017/1027/thumbnail.jp

Prospectus, October 18, 2017

Parkland police talk face-to-face with students; Parkland to show off at upcoming open house; Blade Runner 2049 a worthy sequel to the sci-fi classic; Midway of Madness serves up frights to the CU area; SciCommons offers one-on-one experience for students; Help us help you: mental health at Parklandhttps://spark.parkland.edu/prospectus_2017/1026/thumbnail.jp

Prospectus, November 29, 2017

Parkland organizations here to help with finals; Murder on the Orient Express a modern adaptation of a fantastic mystery; PC students discuss Starbucks cup controversy; Cobras men\u27s basketball wins against Lake Land on Nov. 18; Surveying a viable career option for PC students;https://spark.parkland.edu/prospectus_2017/1031/thumbnail.jp