Determination of Synthetic Food Colors, Caffeine, Sodium Benzoate and Potassium Sorbate in Sports Drinks

Purpose: To employ high performance liquid chromatography (HPLC) techniques to determine edible additives in commercial sports drinks.
Methods: A total of 105 samples including 21 different brands of sports drinks were purchased from markets in Tehran, Iran. The process conditions included a C18 column, a mobile phase consisting of aqueous ammonium acetate buffer (pH = 4.2) and acetonitrile (80:20 v/v) at a flow rate of 0.8 ml min^–1. The injection volume was 20 μL and the UV detector was set at 225 nm.
Results: Mean recovery was between 95 and 106 %. The mean concentrations of sodium benzoate and potassium sorbate in Iranian brands (147.72 and 11.54 ppm, respectively) were significantly higher than in foreign brands (19.43 and 4.91 ppm, respectively, p < 0.05). The maximum amount of sodium benzoate and potassium sorbate was 251.50 ± 18.69 and 96.38 ± 38.56 ppm, respectively, while caffeine content was in the range of 293.48 ± 14.33 - 607.32 ± 135.33 ppm.
Conclusion: HPLC permits the detection of sodium benzoate and potassium sorbate at very low concentrations. Furthermore, caffeine was detected in all the sport drinks. Only Brilliant Blue and Allura Red were detected in the drinks.

Keywords
Edible additives; Sports drinks; Sodium benzoate; Potassium sorbate; Caffeine; Brilliant Blue; Allura Red