In this experiment, as described by scienceprojectlab. You will measure how much of your iodine solution it takes to oxidize a known amount of vitamin C. You can then use your iodine titration solution to determine the amount of vitamin C from test samples of different orange juices.
DCPIP can be used to measure the rate of photosynthesis. If vitamin C, which is a good reducing agent, is present, the blue dye, which turns pink in acid conditions, is reduced to a colorless compound by ascorbic acid. The vitamin C content of food may be reduced by prolonged storage and by cooking because ascorbic acid is water soluble and is destroyed by heat [6,8].
Steaming or microwaving may lessen cooking losses. Fortunately, many of the best food sources of vitamin C, such as fruits and vegetables, are usually consumed raw. Draw up some of the clear liquid into a pipette and then add it, one drop at a time , to a test tube containing a light blue solution of DCPIP.
If the extract is acid the colour will change from blue to red. Continue to add more and see if the colour disappears altogether. A blood test can be taken to measure vitamin C levels and may help to confirm the diagnosis. Your doctor may also suggest some other blood tests to check for other deficiencies in your diet. For example, vitamin C is also needed for the absorption of iron from food.
The direct visual titration of vitamin C with indophenol cannot be used when the vitamin is to be assayed in materials that give deeply coloured extracts. The colorimetric measurement of the large excess of the dye added to the sample-extract in these methods introduces an extra step of photoelectric colorime- try.
Divide the total number of iodine drops by the number of drops per mg of vitamin C from the reference sample. Oxidation and reduction in terms of oxygen transfer Oxidation is the gain of oxygen. Reduction is the loss of oxygen. DCIP 2,6-dichlorophenolindophenol is a dye which is blue in its oxidized form and colorless in its reduced form. The change in absorbance at nm will be used to measure the rate of the Hill reaction.
The change in absorbance will be measured at 1 minute intervals of exposure to an intense light source. This is actually an advantage because it means that the DCPIP can access the thylakoid membranes directly , without having to pass through the outer membranes, to accept electrons directly from the electron transport chain. May be harmful by inhalation, ingestion, or skin absorption.
May cause eye, skin, or respiratory system irritation. This article may be confusing or unclear to readers. Please help us clarify the article. There might be a discussion about this on the talk page. August Learn how and when to remove this template message. Categories : Pages with broken file links Wikipedia articles needing clarification from August Articles with invalid date parameter in template All Wikipedia articles needing clarification Indophenol dyes Redox indicators.
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