Microheterometric titrations of large organic nitrogen-containing compounds and of heteropoly acids

Micro amounts of nitron, quinine, strychnine, papaverine, yohimbine, nicotine, atropine, morphine or phenanthroline were titrated heterometrically with silicotungstic, phosphotungstic or phosphomolybdic acids at pH 1 or 7. The heterometric curves and the compounds obtained were studied. The reverse titrations were also studied. Microheterometric determinations of large nitrogen-containing compounds and heteropoly acids are suggested.