Vitamin C Lab Report
Vitamin C also known as ascorbic acid is vital to our body. It can strengthen our body to resist against infection. It is known that deficiency of vitamin C can cause scurvy. Vitamin C is present in various fruits. Since vitamin C is a reducing agent, it can be deactivated by a wide range of oxidizing agents including atmospheric oxygen. Therefore, precautions are needed to prevent or minimize the degradation of vitamin C during sample preparation.
The ascorbic acid exists in two forms which are the oxidized form called L-dehydroascorbic acid and reduced form which is L-ascorbic acid. Ascorbic acid lost easily due to various factors such as temperature, presence of oxygen, exposure to the light, pH which it is stable in acidic condition …show more content…
In order to maintain the stability of the vitamin C, the extracting solution should be able to denature and precipitate the protein, to prevent oxidation of vitamin C as well as to remove some of the interferences. Therefore, the analytical procedure needs to be performed at low pH and avoid exposure of the ascorbic acid to the light sources. Metaphosphoric acid is employed for these purposes.
In the titration of vitamin C with 2, 6-dichloroindophenol (DCPIP), the added DCPIP will react with the vitamin C in the sample to form colorless products. During the course of the titration, the solution remains colorless until all the vitamin C has been reacted. A few drops of excess DCPIP will turn the solution to reddish solution. Therefore, DCPIP can serve as its own indicator. DCPIP decomposes with time and the decomposition products may affect the observation of end point.
In this experiment, the objective is to determine the ascorbic acid in the juice sample by using 2, 6-dichloroindophenol (DCPIP) titrimetric method which is from the AOAC Method, 45.1.14 Official Method 967.21 Ascorbic Acid in Vitamin Preparations and Juice, 2,6-Dichloroindophenol Titrimetric
The ascorbic acid exists in two forms which are the oxidized form called L-dehydroascorbic acid and reduced form which is L-ascorbic acid. Ascorbic acid lost easily due to various factors such as temperature, presence of oxygen, exposure to the light, pH which it is stable in acidic condition …show more content…
In order to maintain the stability of the vitamin C, the extracting solution should be able to denature and precipitate the protein, to prevent oxidation of vitamin C as well as to remove some of the interferences. Therefore, the analytical procedure needs to be performed at low pH and avoid exposure of the ascorbic acid to the light sources. Metaphosphoric acid is employed for these purposes.
In the titration of vitamin C with 2, 6-dichloroindophenol (DCPIP), the added DCPIP will react with the vitamin C in the sample to form colorless products. During the course of the titration, the solution remains colorless until all the vitamin C has been reacted. A few drops of excess DCPIP will turn the solution to reddish solution. Therefore, DCPIP can serve as its own indicator. DCPIP decomposes with time and the decomposition products may affect the observation of end point.
In this experiment, the objective is to determine the ascorbic acid in the juice sample by using 2, 6-dichloroindophenol (DCPIP) titrimetric method which is from the AOAC Method, 45.1.14 Official Method 967.21 Ascorbic Acid in Vitamin Preparations and Juice, 2,6-Dichloroindophenol Titrimetric