Spectrophotometric determination of trace amounts of hydrazine in polluted water

A sensitive spectrophotometric method is proposed for the determination of trace amounts of hydrazine by a one-step condensation reaction with vanillin. The dye thus formed gives a yellow colour in acidic medium, has a maximum absorbance at 400 nm and obeys Beer's law in the range 0.65–5 µg of hydrazine in 10 ml of the final solution. The optimum reaction conditions, such as time, temperature, pH, reagent concentration and effect of interferents, were determined for full colour development. The method has been applied successfully to the determination of hydrazine in polluted river water and in a biological fluid.