The HI93704-03 are high quality reagents that are pre-measured, allowing for users to achieve fast and accurate colorimetric measurements. These reagents follow the ASTM Manual of Water and Environmental Technology, Method D1385-88 in which the reaction between hydrazine and p-dimethylaminobenzaldehyde reagent causes a yellow tint in the sample. By simply adding the reagent to the sample, a reaction will take place and a compatible benchtop or portable meter can be used to determine the concentration from the color that is produced. The results will be displayed in µg/L (ppb) of hydrazine. These reagents are designed to be used with samples that have an expected range of 0 to 400 µg/L hydrazine.