pH is an important factor, together with oxygen

Dear Abolfaz, As you know, stabilizing is a multi factors process. At first let me know, about the sample which you want stable Vitamin-C in it. Your sample is liquid or solid? if liquid, solvent is water? distilled water? buffer?if it is buffer, its pH? Concentration? kind of buffer?  The solution is only vitamin-C solution or it has other components? other components is clear for you or not? other components are simple molecules or macro molecules? they have oxidation reduction activity or not?  if you give us more information, I think, vitamin-C stabilizing is possible.

best

mehdi

Thanks for your answers.

My mean is in vivo.