The HI94767A-50 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 chromotropic acid method in which a digestion is required to convert all forms of nitrogen to nitrate. Sodium metabisulfite is added to remove potential interferences. The reaction between nitrate and the reagents causes a yellow tint in the sample. The intensity of color is determined by a compatible photometer and the concentration will be displayed in mg/L (ppm) as total nitrogen. These reagents are designed to be used with samples that have an expected range of 0.0 to 25.0 mg/L (ppm) nitrogen.

Hanna vials contain pre-dosed reagent so the user simply needs to add the sample and provided reagents in accordance with the instructions to achieve the desired reaction. With pre-dosed vials, test preparation time is dramatically reduced and there is no time-consuming reagent preparation procedure or glassware cleaning. The vials and caps of the reagents have been designed to avoid accidental reagent spills. Due to the pre-dosed reagents, the amount of chemicals and handling time is also minimized. These vials feature Hanna’s barcode recognition system exclusive to the HI83224 Wastewater Treatment benchtop photometer. The meter scans each vial to automatically identify sample method and range, however for low range total nitrogen only the reagent vial is recognized, not the digestion vial. The barcode has four digits: the first two digits are for parameter identification and the second two digits are for reagent lot ID. Vials for different methods can be distinguished by a barcode printed on the vial and the cap color.