Spectrophotometric determination of hydrazine

Hydrazine is determined spectrophotometrically by forming the derivative 2,4-dinitrophenylhydrazine from 2,4-dinitrochlorobenzene. The formed dinitro derivative undergoes condensation reaction to form the hydrazone with p-dimethylaminobenzaldehyde (P-DAB). The resulting yellow colored product is stable in acidic medium and has a maximum absorption at 458 nm. The colour system obeys Beer's law in the range 0-7 mu g of hydrazine in an overall volume of 25 mL. The molar absorptivity is calculated to be 8.1 x 10(4) L mol(-1) cm(-1) with a correlation coefficient of 0.998. The relative standard deviation is 1.7% (n = 10) at 6 mu g of hydrazine. Interferences due to foreign ions have been studied and the method has been applied for the determination of hydrazine in boiler feed water. (C) 2007 Elsevier B.V. All rights reserved.