Determination of ascorbic acid in pharmaceuticals and urine by reverse flow injection

Abstract

Two reverse flow injection (Fl) methods, using spectrophotometric detection, are proposed for the determination of ascorbic acid. Both methods are based on its reaction with the ethylenediaminetetraacetic acid—Co^III complex in a medium of 5% diethylamine. In the first method, using the peak-height Fl technique, ascorbic acid is determined over the range from 2 × 10^–4 to 5 × 10^–3 mol dm^–3 and in the second, using the peak-width Fl method, the working range is extended (2 × 10^–3–5 × 10^–2 mol dm^–3). Both Fl methods were applied to the determination of ascorbic acid in pharmaceuticals while the peak-height Fl technique was also used to determine ascorbic acid in urine.