Determination of hydrazine in technological water of power facilities

A comparison was made of three spectrophotometric methods of determining hydrazine in technological water used in conventional and nuclear power plants. In two methods an alkali-acid solution and in the third an aqueous-acid solution of p-dimethylamine benzaldehyde was used as a colour reagent. The results showed that owing to the low velocity of colouring when alkali-acid reagents were used it was necessary to accurately observe the time of measurement, otherwise considerable errors occurred in hydrazine determination. This shortcoming was not observed with the aqueous-acid reagent. It was also found that all three methods of measurement were considerably temperature dependent. With regard to the investigated range of hydrazine concentration which amounts to the order of tens of micrograms per kilogram, the detection limit was adequate for all three methods. Alkali-acid reagents have shorter stability times, merely several days, while the aqueous-acid reagent's life exceeds two years. The method based on the aqueous-acid reagent was the least costly when 100 analyses had been done. (Z.M.). 3 figs., 4 tabs., 14 refs