An improved procedure for application of the Fujiwara reaction in the determination of organic halides

Abstract

Fujiwara discovered that when chloroform or other organic halides are heated with pyridine and sodium hydroxide a red colour is formed. Some halides react very sensitively, others weakly or not at all, depending on many factors.A standard procedure involving this reaction is recommended for use in analytical toxicology and information on sensitivities of twenty-two organic halides when using this procedure is presented. This information permits accurate interpretation concerning the presence or absence of organic halides.Some commercial samples that gave a positive Fujiwara test reacted negatively after being purified by distillation or gas-liquid chromatography and the literature on positive Fujiwara reactions should therefore be consulted.Methods for the determination of an organic halide on the basis of the Fujiwara reaction should be used only when all other reactive halides are absent.