HI97751 is an advanced portable photometer for the measurement of sulfate in water. This meter offers a superior optical system that utilizes a reference detector and narrow band interference filters for extremely fast and repeatable measurements.
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Sulfate is widely present within natural waters in different concentrations. Sulfate concentration is to be kept within a strict range for drinking water, especially since this value can be high near mine drainage points. Sulfate is also rigorously tested in the production of beverages such as beer, due to its significant effect upon odor and taste.
The HI97751 uses an adaptation of the turbidimetric method to measure sulfate concentrations of less than 150 mg/L (ppm). When the reagent is added to a sample containing sulfate, it will cause turbidity in the sample; the greater the concentration, the greater the color and turbidity change. 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 sulfate determination, a narrow band interference filter at 466 nm allows only blue light to be detected by the silicon photodetector and omits all other visible light emitted from the LED. As the change in color of the reacted sample increases, absorbance of the specific wavelength of light also increases, while transmittance decreases.
The HI97751 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.
HI97751 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.

Backlit Display
Backlit dot matrix LCD that offers an exceptionally intuitive user interface that is easy to read and understand.

Tutorial Mode
Tutorial mode for step-by-step instructions to guide a first-time user in how to perform a measurement correctly.

Reaction Timer
Built-in reaction timer that ensures consistency amongst multiple users.
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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