Murexide

• 3051-09-0
• 6032-80-0 (as monohydrate )

Dark brown solid

Fixed

> 300 ° C

• Poorly in water (1 g · l -1)
• Insoluble in ethanol and diethyl ether

Template: Infobox chemical / molecular formula search available

Murexide (acid ammonium salt of the non-existing in the free state purple acid C8H5N5O6 ) is an indicator for the titration of metals. Murexide is also the end product of the murexide reaction, a chemical reaction for the detection of uric acid, xanthine and related substances.

Properties

Murexide forms a red-brown powder that is insoluble in ether and alcohol, and in water at 20 ° C little ( 1 g / l) solves. In hot water, it dissolves better. The color changes with the addition of alkali from red to blue. Murexide is used in the pH range of 9 to 12 as a metal indicator in the titration of nickel, cobalt, copper, and calcium chelation (III ) solutions (color change from yellow or red to blue violet), and for cerimetrischen fluorine determination.

History

That it is the murexide to the acid ammonium salt of purpuric acid, was described by Friedrich Konrad Beilstein in his 1858 custom built with Friedrich Wöhler in Göttingen dissertation "On the murexide "; in Beilstein it says "acid purple ammonia ".