title: Simultaneous and rapid determination of caffeine and taurine in energy drinks by MEKC in a short capillary with dual contactless conductivity/photometry detection.
abstract: A method has been developed for the simultaneous determination of taurine and caffeine using a laboratory-made instrument enabling separation analysis in a short 10.5 cm capillary. The substances are detected using a contactless conductometry/ultraviolet (UV) photometry detector that enables recording both signals at one place in the capillary. The separation of caffeine and taurine was performed using the MEKC technique in a BGE with the composition 40 mM CHES, 15 mM NaOH, and 50 mM SDS, pH 9.36. Under these conditions, the migration time of caffeine is 43 s and of taurine 60 s; LOD for caffeine is 4 mg/L using photometric detection and LOD for taurine is 24 mg/L using contactless conductometric detection. The standard addition method was used for determination in Red Bull energy drink of caffeine 317 mg/L and taurine 3860 mg/L; the contents in Kamikaze drink were 468 mg/L caffeine and 4110 mg/L taurine. The determined values are in good agreement with the declared contents of these substances. RSD does not exceed 3%.
authors.affiliation: Faculty of Science, Department of Analytical Chemistry, Charles University in Prague, Albertov, Prague, Czech Republic.
authors.forename: Blanka
authors.initials: B
authors.lastname: Vochyánová
authors.forename: František
authors.initials: F
authors.lastname: Opekar
authors.forename: Petr
authors.initials: P
authors.lastname: Tůma
mesh_terms: D002110:Caffeine / Q000032:analysis*; D020374:Chromatography, Micellar Electrokinetic Capillary / Q000191:economics / Q000295:instrumentation*; D003217:Conductometry / Q000191:economics / Q000295:instrumentation; D004553:Electric Conductivity; D061215:Energy Drinks / Q000032:analysis*; D004867:Equipment Design; D057230:Limit of Detection; D010783:Photometry / Q000191:economics / Q000295:instrumentation; D013654:Taurine / Q000032:analysis*
chemical_list: D013654:Taurine; D002110:Caffeine
keywords: Caffeine; Dual detection; Energy drinks; Micellar electrokinetic chromatography; Short capillary separation; Taurine