The online community and resource center for all in life science related disciplines (BIOSCIENTISTS)
December 16, 2018, 04:18:12 pm *
Welcome, Guest. Please login or register.

Login with username, password and session length
News: Over 3000 Nigerian Life scientists are on ground & willing to provide answers to your bioscience & research questions/problems; You only need to post it online Now! (Requires very brief registration)

To be kept up to date on interesting posts in this forum,  LIKE our facebook page!
   Home   Help Login Register  
Pages: [1]
Author Topic: ESTIMATION OF ASCORBIC ACID  (Read 11713 times)
0 Members and 1 Guest are viewing this topic.
Francis Umeoguaju
Expert in Bioscience Issues
Posts: 657

« on: April 10, 2010, 08:58:16 am »

Ascorbic acid is oxidized by the blue coloured dye, 2,6-dichlorophenolindophenol
to dehydroascorbic acid; at the same time, the dye is reduced to a colourless compound so that the end point of the reaction can be easily determined.

   2,6-dichlorophenolindophenol, (3.2g of the dye was dissolved in about 40ml of hot  water, this is cooled and made up to 50ml with distilled  water)
   20mg/1000ml solution of standard vitamin C is prepared just before use
   Diluted sample that have vitamin C concentration of about 0.1mg.
   Glacial acetic acid


   5ml of the sample is mixed with 1ml of glacial acetic acid, the mixture is then titrated with the dye solution until the blue dye changes to a permanent pick colour. The titre value is noted. Strove et al suggests an end point of a pink colour that remains visible within 30 seconds.
   The titration is repeated with 5ml of water for the Blank 5ml ascorbic acid standard solution. The vitamin C content of the sample is calculated as follows:
Vit. C of test (mg/100ml)= ((T-Blank) X 2 X dilution)/

T-Titre of samples
St= standard


Chances favours the trained minds
Pages: [1]
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC
SMFAds for Free Forums
Valid XHTML 1.0! Valid CSS!