Determination of Vitamin C Content in Dietary Supplements

Abstract

This research focused on determination of vitamin C content in pharmaceutical preparations using the titrimetic method of analysis. The content of vitamin C (ascorbic acid) was measured in twelve preparations. Pharmaceutical preparations that were used for the analysis were supplied in retail, on the territory of Republic of Srpska. For the determination of a substance content, the volumetric method, iodometry, was used. The method is based on determining the volume of a reagent with a known concentration needed for complete reaction with the test substance. In the iodometry, iodine is reduced by ascorbic acid and when it all is reacted, iodine that is in excess forms a blue-black complex with starch indicator, which marks the ending point of the titration.
Based on the results obtained during the experimental work, it is evident that the percentage content of vitamin C in the compositions is in the interval from 95.24 to 99.64 %. Deviations from the prescribed values are not larger than 5 %. This analysis concluded that the highest percentage of vitamin C include samples of DM (99.64 %), Biofar’s (99.64 %) and Pliva sample tablets with sustained release (99.50 %). The lowest percentage was determined in a sample Eunova-Multi-Vitalstoffe (95.24 %).