Simultenious Estimation of Sodium Benzoate and Caffeine in Soft Drinks by UV Spectroscopy

Abstract

A simple spectrophotometric methods have been developed for the simultaneous estimation of sodium benzoate and caffeine from the food products Method-I simultaneous equation method involves the measurement of absorbance at two wavelengths 224nm (λ max of sodium benzoate) and 274nm (λ max of caffeine) using Water as diluent. Method – II Absorption ratio method involves the measurement of absorbance at two wavelengths 274nm (λ max of caffeine) and 241nm (λ max of Isobestic point). The method was validated as per ICH guideline rules in terms of accuracy (recovery study), precision, ruggedness, robustness and the validation parameters were within acceptable limits. The percentage recovery at various concentration levels varied from 99.5 to 100.6% for sodium benzoate and 99.3 to 98.3% for caffeine. Two popular soft drink brands were purchased from supermarket and evaluated for sodium benzoate and caffeine by simultaneous equation method and Q-absorption ratio method. The amount of sodium benzoate and caffeine found in sample 1is 150µg/ml and139µg/ml and in sample 2 is 179µg/ml and 190µg/ml respectively.