Non-aqueous redox determination of ascorbic acid with copper (II)

Area of Science:

• Analytical Chemistry
• Electrochemistry

Background:

• Ascorbic acid (Vitamin C) is a vital nutrient with various biological roles.
• Accurate determination of ascorbic acid is crucial in food science, pharmaceuticals, and clinical diagnostics.
• Existing methods for ascorbic acid quantification may require complex procedures or specialized equipment.

Purpose of the Study:

• To develop a direct, visual, and potentiometric method for ascorbic acid determination.
• To utilize hydrated copper (II) perchlorate as a titrant in acetic acid-acetonitrile media.
• To establish a simple, accurate, and reliable analytical procedure.

Main Methods:

• Direct titration using hydrated copper (II) perchlorate in acetonitrile.
• Visual endpoint detection with diphenylamine or diphenylbenzidine indicators.
• Potentiometric titration employing a bright platinum wire as the indicator electrode and a modified calomel or antimony electrode as the reference electrode.
• Oxidation of ascorbic acid to dehydroascorbic acid.

Main Results:

• Hydrated copper (II) perchlorate in acetonitrile enables direct visual and potentiometric determination of ascorbic acid.
• Diphenylamine and diphenylbenzidine were identified as suitable indicators for the visual method.
• The method demonstrated simplicity, accuracy, and reliability.
• Reverse titration procedures were also found to be effective.

Conclusions:

• The proposed method offers an efficient and dependable approach for ascorbic acid quantification.
• The use of copper (II) perchlorate provides a straightforward titrant for this analysis.
• Both visual and potentiometric techniques, along with reverse titration, are viable for accurate ascorbic acid measurement.