HI97779 is an advanced portable photometer for the measurement of chlorine dioxide in water. This meter offers a superior optical system that utilizes a reference detector and narrow band interference filters forextremely fast and repeatable measurements.
Used primarily as a disinfectant in drinking water and in various industrial processes, chlorine dioxide is a highly effective, environmentally friendly microbiocide. Chlorine dioxide is safe, potent, and does not produce trihalomethanes, the disinfection byproduct characteristic of chlorine use.
The HI97779 uses an adaptation of Standard Methods for the Examination of Water and Wastewater, 23rd Edition, 4500 ClO2D to measure chlorine dioxide concentrations of less than 2.00 mg/L (ppm). When the chlorophenol red reagent is added to samples containing chlorine dioxide, the purple hue from the reagent will lessen. The greater the concentration, the greater the discoloration. The associated color change is then colorimetrically analyzed according to the Beer-Lambert Law. This principle states that light is absorbed by a complementary color, and the emitted radiation is dependent upon concentration. For chlorine dioxide determination, a narrow band interference filter at 525 nm allows only green-yellow light to be emitted and passed through the sample cuvette. As the change in color of the reacted sample increases, absorbance of the specific wavelength of light also increases, while transmittance decreases. Using a pre-programmed curve a result is then displayed.
The HI97779 has an innovative optical system that offers superior performance in accuracy, repeatability, and the short amount of time it takes to perform a measurement. This compact, waterproof meter is extremely user friendly with a tutorial mode that walks the user graphically, step by step, in performing a measurement. The use of a backlit dot matrix LCD allows the use of virtual keys which makes the operation of the meter very intuitive including selecting different units of measure, reviewing GLP data, recalling the last 50 measurements, and customizing the meter to user preferences.
HI97779 is completely waterproof including the cuvette holder that is designed with ridges to protect the optical path from getting scratched by the cuvette and a gasketed battery compartment that holds three common AA batteries. The compact design fits comfortably in the hand for use in the field or on a table for benchtop use. The LCD is backlit for easy viewing under all conditions.


CAL Check
Advanced features including CAL-Check to verify performance and if necessary, recalibrate.

Setup Options
Setup options for meter personalization include date and time format, language, and enabling the tutorial mode.

Tutorial Mode
Tutorial mode for step-by-step instructions to guide a first-time user in how to perform a measurement correctly.
Stable Light Source:
High Efficiency Light Source:
High Quality Filters:
Greater Light Yield:
CAL Check Functionality:
Large Cuvette Size:
Intuitive Dot Matrix Display:
Auto-off Protection:
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