ThermaNin is a ninhydrin derivative for developing fingerprints
on thermal paper. Regular ninhydrin and DFO solutions are
either based on polar solvents (like acetone or ether) or contain
them. These turn the top (active) layer of thermal paper gray
or black. Research has found that hemiketals of ninhydrin are
soluble in petroleum ether (or other apolar solvents like pentane,
heptane) without the need for addition of polar solvents.
ThermaNin develop fingerprints on thermal paper without darkening
of the surface.
1g