After nitrate was reduced by copper-coated cadmium granules,the nitrite produced was determined by diazotization of fuchsin acid and coupling to resorcinol.

• 采用镀有铜的镉还原硝酸盐(NO-3 )为亚硝酸盐(NO-2 )后,于酸性条件下,将品红与NO-2 进行重氮化,再与间苯二酚在弱碱介质中偶合成稳定的橙色染料。