The HI93731-01 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 Standard Methods for the Examination of Water and Wastewater, 20th edition, Zincon method. The reaction between zinc and the reagents causes a brownish-green to a blue tint in the sample. By simply adding the reagents to the sample, a reaction will take place and a compatible benchtop or portable meter can be used to determine the concentration. The results will be displayed in mg/L (ppm) of zinc. These reagents are designed to be used with samples that have an expected range of 0.00 to 3.00 mg/L zinc.