Quantitation of Caffeine by Capillary Zone Electrophoresis with End-Column Amperometric Detection at a Carbon Microdisk Array Electrode
Open Access
- 1 January 2000
- journal article
- research article
- Published by Oxford University Press (OUP) in Journal of Chromatographic Science
- Vol. 38 (1) , 11-15
- https://doi.org/10.1093/chromsci/38.1.11
Abstract
Capillary zone electrophoresis is employed for the determination of caffeine using end-column amperometric detection with a carbon fiber microdisk array electrode at a constant potential of 1.45 V versus a saturated calomel electrode. The optimum conditions of separation and detection are 0.152mM NaH2PO4−0.648mM Na2HPO4 for the buffer solution, 20 kV for the separation voltage, 5 kV for the injection voltage, and 10s for the injection time. The limit of detection is 2.9 × l0−4mM or 1.2 fmol (signal-to-noise ratio = 2). The relative standard deviation is 0.68% for the migration time and 2.3% for the electrophoretic peak current. The method is applied to determining caffeine in human serum and a cola drink.Keywords
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