A fast, simple and cost-effective capillary electrophoresis (CE) method was developed for caffeine determination in different beverages (energy drinks, soft drinks). Because caffeine is neutral from electrophoretic point of view and migrates with the electroosmotic flow (EOF), micellar electrokinetic chromatography (MEKC) was chosen as the separation method. The optimum separation conditions consisted of 25 mM sodium tetraborate, 100 mM sodium dodecyl sulphate, pH 9.30, 20°C temperature, 20 kV voltage, 50 mbar/sec hydrodynamic injection, UV detection at 270 nm. Employing the optimized conditions caffeine was quantified in less than 3 minutes. The analytical performances of the method were verified in terms of accuracy, linearity, limit of detection and quantification, precision and robustness. The method was applied also to detect caffeine in coffee and tea. The advantage of MEKC over other analytical methods, particularly compared with the more frequently used HPLC methods, lies in its lower operating costs and higher environmental friendliness.
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Benzene Determination in Soft Drinks
Objectives: Benzene is a known human carcinogen. We are exposed to benzene mainly through inhalation and a lesser extent through the ingestion of food and water. Benzene is formed in beverages when ascorbic acid coexists with benzoate salts. Certain additional conditions (heat, UV light, metallic ions) are required for detectable levels of benzene to be formed. The aim of this study was to investigate soft drinks for the presence of benzene.
Methods: A GC method was developed to identify and quantify benzene in beverages. Fifteen samples containing benzoate sodium and ascorbic acid were analyzed.
Results: The benzene concentration ranged between the limit of quantification and 8.81 µg/l. The EU guideline limits the benzene concentration at 1 µg/l in drinking water; 6 of the products tested were above this admitted level.
Conclusion: Based on the presented data, the safety of benzene as a preservative agent should be reconsidered.