Griess reagent is a crystalline powder of white, gray or purplish-pink color.
Griess reagent was used to detect organic compounds that are released during heating of HNO2. Today the selection so nitrite is also called the method of Griess, after the English chemist who developed it.
Griess reagent made can only be used on the day when the two components were mixed solution thereof. A components themselves can be made in advance.
A solution of a-naphthylamine require storage in a dark place, where there is no access to sunlight. Properly prepared solution has a light gray color. If another shade - red or pink, then Griess reagent is unfit for use in the initial reagents were nitrogenous compounds.
According to the degree of danger Griess reagent refers to the 2-3 class. Work with the substance should be allowed only to experts with specialized skills and knowledge.