Determination of nicotinic acid etc. In human urine and stool (II)

Abstract A routine method is given for the determination of nicotinic acid and trigonelline in normal as well as in highly coloured urine. Both compounds are excreted quite constantly; orally administered nicotinic acid and nicotinamide affect the quantities excreted to different degrees. In faeces it is chiefly nicotinic acid which is encountered; the amounts are not increased by a large dose of nicotinic acid (nicotinamide) taken through the mouth. In order to avoid disturbing secondary colour reactions the nicotinic acid is purified by oxidation and adsorption on franconite; the trigonelline is determined by colorimetry of the dialdehyde which is formed from it by hydrolysis with alkali. A large part of orally taken nicotinic acid (amide) could not be recovered from the excreta. A remarkable reaction of the trigonelline is described. It is found that the colour reaction in the form given until now is not sufficiently specific. A large part of orally taken nicotinic acid (amide) could not be recovered from the excreta. A remarkable reaction of the trigonelline is described. It is found that the colour reaction in the form given is not sufficiently specific.