Phosphomolybdic acid, also known as dodeca molybdophosphoric acid or PMA is a component of Masson's trichrome stain. Phosphomolybdic acid is a yellow-green compound, freely soluble in water and polar organic solvents such as ethanol. Phosphomolybdic acid is used as a reagent in thin layer chromatography for staining phenolics, hydrocarbon waxes, alkaloids and steroids.