The HI93728-03 are high quality reagents that are pre-measured, allowing for users to achieve fast and accurate colorimetric measurements. The method is an adaptation of the cadmium reduction method in which the reaction between nitrate and the reagent causes an amber tint in the sample. The intensity of color is determined by a compatible photometer and the nitrate concentration will be displayed in mg/L (ppm) as nitrate-nitrogen (NO3--N). These reagents are designed to be used with samples that have an expected range of 0.0 to 30.0 mg/L (ppm) nitrate-nitrogen.