Sequential Injection Spectrophotometric Determination of Ascorbic Acid in Pharmaceutical Preparations Using Potassium Permanganate
Abstract: A reliable and sensitive indirect sequential injection method with spectrophotometric detection for the determination of ascorbic acid in various pharmaceutical preparations is proposed in this paper. The method is based on a redox reaction between ascorbic acid and permanganate in 0.1 mol L–1 sulphuric acid medium. The fading permanganate color as a result of the proposed reaction, was measured at 548 nm. The method involved the injection of 250 μL of ascorbic acid sample or standard, into the holding coil containing potassium permanganate as carrier solution. In the next step the injected volume of standard or sample is dispensed through the detector. This simple two step procedure enables high sample throughput of 240 h–1. The relative standard deviation was calculated to be 0.35 %. The obtained results by the proposed method were found to be in good agreement with the standard titrimetric method. The proposed method is simple and cost-effective and also can be an alternative to more sophisticated methods. The method is suitable for a quick and sensitive quantitative analysis of ascorbic acid in pharmaceutical preparations.
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