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Disposable Nafion-modified Screen-printed Graphite Electrodes for the Rapid Voltammetric Assay of Caffeine
Autoři: Valassi Lydia | Tsimpliaras Dimitrios | Katseli Vassiliki | Economou Anastasios | Švancara Ivan | Stočes Matěj | Mikysek Tomáš | Prodromidis Mamas
Rok: 2015
Druh publikace: článek v odborném periodiku
Název zdroje: Insights in Analytical Electrochemistry
Strana od-do: 1-8
Tituly:
Jazyk Název Abstrakt Klíčová slova
cze Jednorázové nafionem modifikované uhlíkové tištěné elektrody pro rychlé voltametrické stanovení kofeinu Cílem práce byl vývoj Nafionem modifikované uhlíkové tištěné elektrody pro voltametrické stanovení kofeinu. Validace metody byla provedena pro vzorky nápojů obsahujících kofein. uhlíkové tištěné elektrody; Nafion; voltametrie; kofein; vzorky nápojů; káva
eng Disposable Nafion-modified Screen-printed Graphite Electrodes for the Rapid Voltammetric Assay of Caffeine Objective: The aim of this work was the development of Nafion-modified disposable screen-printed graphite electrodes for the voltammetric determination of caffeine and the validation of a method for the rapid voltammetric assay of caffeine in drinks and coffee. Methods: A Nafion-coated screen-printed graphite electrode (fabricated by immersion in a 0.25% (w/v) Nafion solution) was used a working electrode and voltammetry was performed in the differential pulse (DP) mode (initial potential, +0.90 V; final potential, +1.70 V vs. Ag/AgCl (sat. KCl)) in 0.2 mol L-1 H2SO4. Results: Modifying the electrode with a Nafion film improved the sensitivity, the repeatability and the resistance of the electrode towards surface-active compounds. The limits of detection (LOD) and quantification (LOQ) were 0.2 and 0.6 mg L-1, respectively, while the % relative standard deviation (n=8) was 1.3% and 2.8% for 2.0 and 10 mg L-1 caffeine, respectively. The proposed sensors were successfully applied to determine caffeine in samples of energy and cola drinks and instant coffee with recoveries between 97 and 103% and satisfactory agreement with the reference HPLC method. Conclusions: The proposed Nafion-coated screen-printed electrodes are inexpensive and easy to fabricate, disposable, resistant to electrode fouling, do not require activation/cleaning or complex modification protocols and are fit-for-purpose for the task of the rapid voltammetric assay of caffeine. Screen-printed graphite electrodes; Nafion; Voltammetry; Caffeine; Drink samples; Coffee