I was doing research related to the analysis of cyanide with ninhydrin, in some journals mentioned that preparation ninhydrin by dissolving it in sodium carbonate, but I do not understand why. Is there any effect if I dissolved it in any solvent? Thank you anyway :)
Hi I dissolved ninhydrin in citric acid with sodium molybdate, which served as a reagent for amino acids assay. I tried dissolve it in water without citric acid, it still able to develop purplish colour using a same method.
I suppose carbonate was used to prevent cyanide loss as hydrogen cyanide thus the pH of solution was adjusted to alkaline solution.
Anyway here's a reference journal. Hope it helps.
It may be that ninhydrin is more stable in carbonate. I suspect that the condensation with an amine or amino acid to form the Schiff is acid catalysed, so this may be a way of preserving the reagent until it is mixed with the test solution.
Thank you OOi Yan Jie and David Walwyn :)
Yes, I agree that sodium carbonat used to make alkaline solution and more stable. But, what the effect if using sodium phosphate? In some journals explain that sodium carbonate is more stable, but there is no reason why. Or it depends on characteristic or another reason? Anyway, here's the journal
I am only guessing but it may be more stable in carbonate since the dissolved CO2 may drive the equilibrium towards ninhydrin.
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