Difference between revisions of "サイクリックボルタンメトリー -抗酸化剤分析-"

Revision as of 19:37, 22 January 2014

Figure 1. CV of a cream base with 1.0% sodium ascorbate.

Figure 2. CV of Black Tea

The EChem Startup System can be used to analyse antioxidants using Cyclic Voltammetry

Introduction

サイクリックボルタンメトリ(CV)はオイル、食品、医療、農産業分野で使われている抗酸化剤の評価に用いられています。

CV は抗酸化剤の簡便な定量法として、また必要最小添加量の試験などに広く用いられています。電極に印加電圧を架け、両電圧間をスイープさせます。電圧によって抗酸化剤から電子が失われると電流が発生し、ある電圧で電流シグナルにピークが生じます。これらのピークを示す電圧値から抗酸化物の種類が、ピークの高さと面積から含有量が分かります。. The voltage at which these peaks occur indicates the type of antioxidant, while the current peak height and area reflect the amount of antioxidant present.

Antioxidants in Cosmetics

Antioxidants are a key ingredient with claimed anti-aging effects in many skin care products. They are claimed to provide reparative benefits and to afford protection against exposure to pollution and UV radiation. Quantifying the level of antioxidants in cosmetic raw materials allows the formulator to choose the exact level of protection offered by the product.

Cyclic voltammetry is an affordable, robust tool for measuring the antioxidant capacity of plants, extracts, and formulations. In addition to its role in research, it is well suited for collecting quality control data and optimising extraction procedures. It is a simple way to measure and document the antioxidant capacity of a given substance. Figure 1 shows the voltammogram of a cream base with 1.0% sodium ascorbate.

Antioxidants in Food

Many foodstuffs contain high levels of antioxidants. In fruit juices and plant extracts the main antioxidants are vitamin C (ascorbic acid), and an array of polyphenolic compounds. 'Staleness' of a food is often due to gradual oxidation (by air) leading to loss of the antioxidants, and monitoring of the 'total antioxidant level' in a foodstuff is often an indicator of its freshness and quality. 'Total antioxidant level' is usually quoted by referencing back to an equivalent amount of vitamin C (in aqueous samples) or vitamin E (for fat soluble antioxidants). The EChem Startup System has been used to perform cyclic voltammetry on a range of beverages. Figure 2 shows the antioxidant peaks (due to polyphenolic tannins) in the cyclic voltammogram of black tea.

Antioxidants in Medicine

CV with the EChem Startup System can be used for the analysis of antioxidant levels in blood plasma, which can be used to determine the effects of diet, stress, and infection in suitable animal models. Antioxidant levels can also be quantified in traditional medicines.