FLOW-INJECTION TITRIMETRIC ANALYSIS OF VITAMIN-C IN PHARMACEUTICAL PRODUCTS

A flow injection titrimetric method for the assay of vitamin C using c erium(IV) was developed. A 157 mul vitamin C solution was injected int o a carrier stream of 7.48 x 10(-3) M cerium(IV) prepared in 0.10 M su lfuric acid flowing at a rate of 5.0 ml/min. A 1.3 ml mixing chamber w as employed for dispersion of the resultant solution which was propell ed through a flow-through cell and detected using the spectrophotomete r at a wavelength monitored at 410 nm. The method was applied to the d etermination of vitamin C in pharmaceutical preparations and a high ac curacy was attained when compared with the British Pharmacoepeia (BP) method. Excellent precision indicated by a relative standard deviation of less than 0.9% was always obtained. No interferences were encounte red and as many as 36 samples per hour were reached for throughput.