Ascorbic acid estimation

Biochemical identification of bacterial isolates


Ascorbic acid estimation is done by 2,6-dichlorophenol indophenolin which molar solutions of dye are reduced by equivalent molar solutions of the organic acid which further depends on

  1. Elimination of interferring reducing substances such as cysteine, glutathione and other compounds containing sulfhydryl group
  2. Inhibition of the oxidation of ascorbic acid that is present in the samples.


  1. 2,6-dichlorophenol indophenol dye
  2. 3% (v/v) Phosphoric acid
  3. 0.1N Sodium Hydroxide
  4. Titration appratus


  1. 10 mL wine sample was taken to which 10 mL phosphoric acid was added to make a final volume of 20 mL.
  2. Samples were centrifuged at 3000 rpm for & minutes.
  3. Supernatant was collected and titration was performed with the help of 0.1N NaOH and 2,6-dichlorophenol indophenol dye was used as an indicator.
  4. On addition of NaOH drop wise to the sample, appearance of pink colour was noted, which shows the end point and reading was recorded.
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