Ninhydrin recipe

The higher the alcoholic solvent boiling point, the higher the temperatures during TLC development, can be achieved  and therefore, the better the staining is supposed to be. But of course, this depends on the desired working conditions. Besides and for similar reasons, the ninhydrin content may vary within 0.2 - 0.3% w/w.

For spray purpose: 0.25% w/w ninhydrin solution in n-butanol.
For test tube purpose: 0.25% w/w aqueous ninhydrin solution.

0.3% ninhydrin in 95% ethanol has work OK for us.