Determination of pH and caffeine in carbonated soft drinks

Caffeine is a well-known stimulant which is added as an ingredient to various carbonated soft drinks. Caffeine has drawn more attention due to its physiological effects beyond that of its stimulatory effect. Consumers are interested in knowing the exact amounts of caffeine existing in beverages. Therefore, this study was carried out to determine the pH and levels of caffeine in five brands of carbonated available in local market in Iran. Quantitative analysis of caffeine was performed by a simple and fast standard UV spectrophotometric method, using carbon tetrachloride as the extracting solvent. Results showed that the pH of the beverages were slightly acidic ranging from 2.5 and 2.68. The minimum caffeine level was observed in the carbonated soft drink Brand-4 (36±0.69 ppm), while the Brand-2 showed the highest caffeine content (56.7±0.76 ppm). The caffeine content in all the beverage samples analyzed in this study are well below the maximum allowable limits set by ISIRI.

Keywords:

soft drinks , pH , Caffeine , UV