Can i use certain volume of juice to determine the vitamin C content or is it necessary to use certain weight of a sample?
Dear Sudarshan Kharal
For the titration of ascorbic acid by the indophenol method I use to pipette directly between 1 to 10 mL of the fruit juice depending on the expected concentration (do a trial and error assay first), should the juice be easily obtained by just squeezing the fruit (oranges, lemons, tangerines or grapefruits). Even so, I'd rather weigh the sample and express final results as mg% Vit.C, but volumes are O.K. as well (you express results as mg Vit.C./100 mL in this case)
If the sample is a semisolid juicy fruit (apple, pineapple, banana or papaya), I weigh about 50 g, add 50-100 mL water and blend the mixture. You can filtrate the juice if the mixture is too pasty or add an excess titrant and then back-titrate with a standard solution of ascorbic acid. Some harder fruits (guava, unipe mangoes, coconut) might require more water and more blending time.
If alternatively you use a 0,01 M iodine solution as titrating agent and starch as indicator, sample volumes have to be larger, at least 50-100 mL (lemon juice, orange juice, etc). However, for strongly colored juice samples, you can't obviously use these two titration methods, though.
Good luck with your research.
Hi,
In attach file, you can found more method for determine the vitamin C
Kazem Alirezalu
Thank you sir. Helped me get and express the results.
Thanks Maynor Alberto Vargas-Vargas . I was able to perform the test easily.
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