LC-MS analysis of selected food additives and their dietary exposure in some soft drinks sold in Nairobi County, Kenya

Aim The determination of the levels of some food additives (phosphoric acid, sorbic acid and sodium benzoate) and their dietary exposure in soft drinks sold Nairobi, Kenya. Study design: The study used liquid chromatography mass spectrometry (LC-MS) technique in determining the levels of some food additives in soft drinks. The technique was validated using normal parameters. The results obtained were used to calculate the dietary exposure levels of the additives. Methodology: Precision of the procedure was determined by doing replicate measurements from which the mean, standard deviation and coefficient of variation was established. Linearity checking was done by injecting standard solutions in LC-MS and calibration curves obtained for phosphoric acid, sodium benzoate and sorbic acid. The information got was analyzed by applying regression calculations, while one-way ANOVA was used to compare different means in samples at a significant difference of p < 0.05. Results The concentration of sorbic acid in samples, was with a mean of 4.2160 mg/L, ranged between 3.8220 and 6.7140 mg/L, while that of its dietary exposure was 2.6200 mg/L/day. Mean RFD for sorbic acid also analyzed was 3.3690 mg/L/day. The concentration of sodium benzoate was 3.584 and 6.441 ml/L with mean at 4.5991 mg/L. Mean reference dose (RFD) for sodium benzoate analyzed was 0.9631 mg/L/day while its dietary exposure was 1.3633 mg/L/day. Phosphoric acid, ranged between 3.251 and 6.904 mg/L, with a mean value of 4.494 ml/L and its dietary exposure was 0.3180 mg/L. Mean RFD for phosphoric acid was 2.0270 mg/L/day. Conclusion The levels were not significantly different in different soft drinks, and the values were lower than the allowed maximum limit. The dietary exposure levels were below the maximum allowed levels, meaning that the additives levels used were safe.