Define titrimetric method - 2, 6 dichlorophenol indophenol, Biology

Define Titrimetric Method - 2, 6 Dichlorophenol Indophenol Method?

The titrimetric method is a redox titration method which depends on the reduction of the blue dye 2,6 dichlorophenolindophenol to a colourless leuco compound by ascorbic acid in solution or in extracts made out of foodstuff. Ascorbic acid, as you have already studied, is a strong reducing agent because of which it reduces the dye 2,6 dichlorophenolindophenol and itself gets converted to dehydro ascorbic acid. After equivalence point is reached the next drop of dye gives a pink colour to the solution indicating the end point. The dye in this titration is coloured in the oxidized form and colourless in the reduced form. Also the dye is pink in acidic solution and blue in alkaline solution.

The reaction involved in this method is highlighted in Figure

2396_Define Titrimetric Method - 2, 6 Dichlorophenol Indophenol Method.png

Figure: Conversion of ascorbic acid to dehydro ascorbic acid

In acidic solution the pink dye is reduced to a colourless substance in presence of ascorbic acid. The solution remains colourless as more dye is added until all the ascorbic acid has reacted. As soon as the next drop of dye solution is added the solution becomes light pink due to excess dye indicating that the end point of the titration has reached. The solution of ascorbic acid or its extracts are prepared in metaphosphoric acid or glacial acetic acid or a mixture of the two. The acid prevents the oxidation of   ascorbic acid due to oxygen in the atmosphere which is faster in presence of metal ions like Fe3+ and Cu2+. Metaphosphoric acid can also form complexes with metal ions which reduces the catalytic oxidation of ascorbic acid. In foods, metaphosphoric acid releases the ascorbic acid from proteins and inactivates ascorbic acid oxidase.

Posted Date: 6/18/2013 1:24:47 AM | Location : United States







Related Discussions:- Define titrimetric method - 2, 6 dichlorophenol indophenol, Assignment Help, Ask Question on Define titrimetric method - 2, 6 dichlorophenol indophenol, Get Answer, Expert's Help, Define titrimetric method - 2, 6 dichlorophenol indophenol Discussions

Write discussion on Define titrimetric method - 2, 6 dichlorophenol indophenol
Your posts are moderated
Related Questions
What are some examples of the energetic function of organic molecules? As they are complex molecules, presenting lots of chemical bonds, organic molecules keeps large amount of

Explain Microbiological Apparatus and Equipments? It provides an orientation to the various basic equipments, i.e., instruments, tools, glassware and miscellaneous items used i

In humans, starch digestion begins in the buccal cavity, but stops in the stomach .Why?

Explain Poor growth - clinical signs of kwashiorkor? Growth retardation is the earliest manifestation of kwashiorkor, the child will be lighter and shorter than its normal peer

what are the unique characteristics of a flatworm

Illustrate briefly about titanium It is generally accepted that pure titanium has little cytotoxicity and it is suggested that the plaque induced inflammation may be due to cr

what is tissue

Clinical Manifestations Early Symptoms Symptoms are episodic in nature or continuous with very little response to bronchodialators. Productive cough especially on awake

How do biodiversity, the total number of living beings and the biomass respectively vary during the ecological succession? Biodiversity, the number of living beings and the bio