摘要
2-(4-chloro-2-phosphonophenylazo)-7-(4-nitrophenylazo)-1,8-dihydroxy-3,6-napht-halenedisulfonic acid (Chlorophosphonazo-Pn) has been proposed as a sensitive color reagent for the determination of metal ions by spectrophotometry,1,2 but the determination of IO4-by fading reaction of chlorophospho nazo-Pn has not been reported.
