Effect of ascorbic acid on neurochemical, behavioral, and physiological systems mediated by catecholamines

Potentiometric Titration of Very Weak Acids: Titration with Hydroxides in Nonaqueous Media Using Glass-Calomel Electrode System

A facile and sensitive spectrophotometric determination of ascorbic acid.

Spectrophotometric determination of micro amounts of ascorbic acid in citrus fruits.

A simple and selective method for the determination of ascorbic acid in pharmaceutical preparations and fresh fruit juices is described. The procedure is based on the reaction of ascorbic acid with the zinc chloride salt of diazotized 1-aminoanthraquinone (Fast Red AL salt) in an acidic medium, followed by development of a blue colour (λmax 630 nm) in alkaline solution. Different variables affecting the colour development were studied and optimized. The method was used to determine between 5 and 25 µg ml–1 of ascorbic acid in the final measured solution. The simplicity of the method permits rapid analysis, suitable for routine control. The method is highly specific for the determination of ascorbic acid in the presence of dehydroascorbic acid and all other vitamins normally encountered with it in pharmaceutical dosage forms. Moreover, the proposed method can also be applied to the determination of ascorbic acid in some fresh fruit juices without interference from coloured and other substances present in the fruit extracts. The reliability of the method was established by parallel determinations against the official British pharmacopoeial method.

C. W. Pifer

Papers

Determination of Ascorbic Acid by New Colorimetric Reaction

Titrations in Nonaqueous Solutions

Colorimetric Determination of Ascorbic Acid

Extraction and Determination of Salts of Organic Bases and Acids

Potentiometric Differentiation of Certain Inorganic Cations