Re: Testing Vitamin C in Orange Juices using Acid/Base Titration

You have a very creative idea, but there are some practical consideration 
which may make what you propose very tricky.

Vitamin C is found in orange juice in milligram quantities (about 60 
milligrams per glass).  One glass of juice is about 250 grams by weight, 
and may contain several grams of citric acid.

This means the magnitude of the vitamin C relative to citric acid is very 
small.  Even if you could titrate the citric acid first, because the 
amount of vitamin C is so small, you run the risk of titrating that too!

I think your best bet is to try to find another way to assay for vitamin C.

Good luck!