Extraction-spectrophotometric determination of hydrazine with 2-hydroxy-1-naphthaldehyde

An extraction-spectrophotometric method for the determination of hydrazine, based on its reaction with 2-hydroxy-1-naphthaldehyde at 100 °C, is described. Beer's law is obeyed between 35 and 700 ng ml–1 of hydrazine. The molar absorptivity at 412 nm is 27 000 l mol–1 cm–1. The method described has been applied satisfactorily to the determination of hydrazine in feed waters for steam-generating boilers.