Sensitive spectrophotometric determination of trace quantities of phenylhydrazine

A method for the rapid and accurate determination of trace quantities of ph enylhydrazine based on its inhibition effect in the reaction between bromat e and hydrochloric acid is developed. The decolorization of methyl orange b y the reaction products was used to monitor the reaction spectrophotometric ally at 525 nm. The method allows the determination of phenylhydrazine in t he range 4.60 x 10(-7)-7.40 x 10(-5) M. The relative standard deviation for 10 determinations of 1.10 X 10(-5) M phenylhydrazine is 0.97% and the dete ction limit of the method is 1.85 x 10(-7) M. The method is applied to the determination of phenylhydrazine in water. (C) 2001 Elsevier Science B.V. A ll rights reserved.