Spectrophotometry Determination of Micro Amounts of Ascorbic Acid in Citrus Fruits Using Iron (III) and Dimethylglyoxime Reagent

I. Z. Al-Zamil, M. A. Al-Hajjaji, S. A. Al-Tamrah, A. M. Aziz-Alrahman and S. M. Sultan

Department of Chemistry, College of Science, King Saud University, Riyadh, Saudi Arabia.

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ABSTRACT:

The described method depends on quantitative oxidation of ascorbic acid, naturally present in citrus fruits with a standard iron (III), followed by complexing the resultant iron (II) with dimethy-Jglyoxime. Forming the stable bisdimethylglyoxime-iron (II) complex. The distinctive red colour of this complex which was extracted with chloroform permits the determination of 0.04-0.50 mole of ascorbic acid with a relative standard deviation of 3%. Expected interferences were eliminated and comparison of the method with the standard iodimstric method gave satisfactory results and the advantages gained are discussed.

KEYWORDS:

Acid; Ascorbic; Dimethylglyoxime; Reagent