Related Experiment Video
Updated: Jun 28, 2026
11:56
A Rapid and Specific Microplate Assay for the Determination of Intra- and Extracellular Ascorbate in Cultured Cells
Published on: April 11, 2014
Coulometric determination of ascorbic acid with electrogenerated octacyanomolybdate(V)
R Cordova-Orellana1, F Lucena-Conde
1Department of Chemistry, Catholic University of Valparaíso, Valparaíso, Chile.
Talanta
|February 1, 1977
Summary
A new electrochemical method accurately measures ascorbic acid using electrolytically generated octacyanomolybdate(V). This coulometric-potentiometric technique offers precision comparable to existing methods for vitamin C analysis.
Area of Science:
- Analytical Chemistry
- Electrochemistry
- Biochemistry
Background:
- Ascorbic acid (vitamin C) is an essential nutrient with various biological roles.
- Accurate quantification of ascorbic acid is crucial for nutritional and clinical assessments.
- Existing analytical methods for ascorbic acid may have limitations in accuracy or precision.
Purpose of the Study:
- To develop and validate a novel coulometric-potentiometric method for ascorbic acid determination.
- To utilize electrolytically generated octacyanomolybdate(V) as a titrant.
- To assess the accuracy and precision of the developed method.
Main Methods:
- A coulometric-potentiometric titration system was employed.
- Octacyanomolybdate(V) was generated in situ via electrochemical reduction.
- The method involved the quantitative reaction between ascorbic acid and the generated titrant.
Main Results:
- The developed method provides a reliable means for ascorbic acid estimation.
- The accuracy and precision of this method were found to be comparable to other established coulometric techniques.
- Successful application of the method for ascorbic acid quantification was demonstrated.
Conclusions:
- Electrolytic generation of octacyanomolybdate(V) offers an efficient approach for coulometric titrations.
- The described coulometric-potentiometric method is a viable alternative for accurate ascorbic acid analysis.
- This technique contributes to the advancement of electrochemical analytical methods for biomolecules.
Related Concept Videos
03:38Polyprotic Acids
Acids are classified by the number of protons per molecule that they can give up in a reaction. Acids such as HCl, HNO3, and HCN that contain one ionizable hydrogen atom in each molecule are called monoprotic acids. Their reactions with water are:
01:18Controlled-Current Coulometry: Coulometric Titration
Coulometric titrations are a form of titrimetric analysis where the reagent is generated electrically, and its amount is evaluated based on current and generating time. The electron serves as the standard reagent. The procedure is similar to conventional titrations, such as endpoint detection.
The fundamental requirements for coulometric titrations are (1) 100% efficiency in the reagent-generating electrode reaction and (2) a stoichiometric and preferably rapid reaction between the generated...
The fundamental requirements for coulometric titrations are (1) 100% efficiency in the reagent-generating electrode reaction and (2) a stoichiometric and preferably rapid reaction between the generated...
01:17Controlled-Potential Coulometry: Electrolytic Methods
Controlled-potential coulometry, also known as potentiostatic coulometry, employs a three-electrode system in which the working electrode's potential is precisely regulated using a potentiostat. Platinum working electrodes are utilized for positive potentials, while mercury pool electrodes are favored for extremely negative potentials. The platinum counter electrode is separated from the analyte using a membrane or salt bridge to avoid interference in the analysis.
The chosen potential ensures...
The chosen potential ensures...
01:20Complexometric EDTA Titration Curves
EDTA titration curves determine the free metal ion concentration. The titration curve represents the change in concentration of free metal ions (p function) as a function of the volume of EDTA added. This curve consists of three regions: before, at, and after equivalence points. Excess free metal ions are present before the equivalence point. Equal concentrations of metal ions and EDTA are present at the equivalence point. After the equivalence point, excess EDTA exists. This means slight...
01:27Controlled-Current Coulometry: Overview
Controlled current coulometry, also known as amperostatic coulometry, is a technique used in electrochemical analysis to measure the quantity of a substance through the controlled passage of current. It involves the application of a constant current to an electrochemical cell containing the analyte of interest. As the current flows through the cell, the analyte undergoes a redox reaction at the electrode surface, resulting in a charge transfer. By monitoring the time required for a certain...
01:23EDTA: Indirect and Alkalimetric Titration
Unlike direct titration, back-titration, and displacement titration, indirect titration is an EDTA titration method for quantifying anions. In the indirect titration method, anions are precipitated as their insoluble salts with excess metal ions. The filtrate containing the excess metal ions is directly titrated with standard EDTA until the endpoint is achieved. Another approach involves extracting the metal ion and back-titrating with standard EDTA to obtain the endpoint. In this way, the...