Ascorbic acid oxidation in SDS micellar systems

Abstract

In this contribution the results of atmospheric and electrochemical oxidation of AA in the SDS micellar solutions and in the microemulsions pentanol/water stabilized by SDS are presented. The hydrophilic vitamin C readily dissolves in water and O/W microemulsions as well as undergoes the irreversible two-electron oxidation reaction. It was found that the atmospheric oxidation of AA is accelerated by the SDS up to the CMC and inhibited in the concentrated SDS solutions. We also found that the rate of atmospheric oxidation of ascorbic acid is higher in the water-in-oil (W/O) than in the oil-in-water (O/W) microemulsions and increases with the increasing oil content. The influence of the SDS on the electrochemical behavior of vitamin C was also studied. The general conclusion emerging from this investigation is that the increasing surfactant concentration shifts the ascorbic acid oxidation potential to higher values whereas the corresponding peak current values diminish. In the microemulsions the AA oxidation is slowed down by increasing the pentanol amount in the system.

MWNT-modified electrodes for voltammetric determination of lipophilic vitamins

“…The electrooxidation of α-tocopherol in microemulsions stabilized by the anionic surfactant sodium dodecyl sulfate [19] and the redox reactions of α-tocopherol in 1,2-dichloroethane with NO and MnO 4 − in water at the water/1,2-dichloroethane interface [20] have been studied by different types of voltammetry. Differential pulse voltammetry (DPV) has been used to evaluate the antioxidant properties of tocopherol monoglucoside towards reactive oxygen species [21].…”

Nitrogen‐protected microwave‐assisted extraction of ascorbic acid from fruit and vegetables

“…As a powerful reducing agent in aqueous solutions, AA can be easily oxidized to dehydroascorbic acid in the presence of some potential factors such as oxygen, heat, light, alkali, trace minerals and hydroperoxides [31]. Solvent extraction (SE) with freezing and mild-temperature-drying procedure was applied to the extraction of AA from plant samples [32].…”

Voltammetric Antioxidant Analysis in Mineral Oil Samples Immobilized into Boron‐Doped Diamond Micropore Array Electrodes

“…Also, the antioxidant properties of drugs can be assessed with voltammetric measurements in organic solvent media such as acetonitrile or ethanol [9]. The use of surfactant stabilized oil-in-water emulsions in voltammetric analysis has been reported for antioxidants that are able to partition into the water phase [10] and for highly water-insoluble oil components with microwave activation [11].…”