Method for simultaneously determining content of reduced ascorbic acid, dehydroascorbic acid and total ascorbic acid in fruit

Abstract

The invention discloses a method for simultaneously determining content of reduced ascorbic acid, dehydroascorbic acid and total ascorbic acid in fruit. The method comprises the following steps: adding oxalic acid into a fresh fruit to extract the total ascorbic acid; separating extracting solution into two portions; adding copper sulfate into one portion for oxidization, and determining the content of the total ascorbic acid by means of a 2,4-dinitrophenylhydrazine colorimetric method; adding an antioxidant, thiourea into the other portion, and determining the content of the dehydroascorbic acid by means of the 2,4-dinitrophenylhydrazine colorimetric method; oxidizing the reduced ascorbic acid in a test sample into the dehydroascorbic acid by activated carbon, then adding 2,4-dinitrophenylhydrazine to generate red osazone, and performing colorimetric determination at a position of 500nm; deducting the obtained content of the total ascorbic acid from the obtained content of the dehydroascorbic acid before the oxidization to obtain the content of the reduced ascorbic acid. According to method disclosed by the invention, the contents of three different kinds of ascorbic acids in fruits such as apple and pear are determined, a standard curve is stable, a linear scope is 1-10mu. g / mL, and a correlation coefficient reaches 0.99 or more.

Description

technical field [0001] The invention belongs to the technical field of vitamin detection, in particular to a method for simultaneously determining the content of reduced form, dehydrogenation form and total ascorbic acid in fruits. Background technique [0002] Vitamin C, also known as L-type ascorbic acid, is an antioxidant. It is named as ascorbic acid because it can cure scurvy caused by lack of vitamin C. It mainly comes from fresh fruits and vegetables. An essential nutrient for organisms, because ascorbic acid is unstable under normal conditions, it has physiological functions, and both reduced and oxidized forms have physiological activities. [0003] Commonly used methods for the determination of VC include 2,6-dichloroindophenol indophenol titration, 2,4-dinitrophenylhydrazine colorimetric method, fluorescence method, potential method and high performance liquid chromatography. 2,6-dichloroindophenol titration, potentiometric titration and high performance liquid c...

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Problems solved by technology

[0004] The purpose of the present invention is to provide a method for simultaneous determination of reduced, dehydrogenated and total ascorbic acid content in fruits, aiming to solve the problem that the commonly used methods for measuring VC are only for the determination of a single reduced ascorbic acid or total ascorbic acid content, facing a large number of samples When it is necessary to measure the three contents of reduced ascorbic acid, dehydroascorbic acid and total ascorbic acid in the sample, several different methods are often used together. The experimental process is time-consuming and the error of the experimental results is relatively large.

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