In domestic water, nitrate is monitored due to the health effects that it has on newborn babies. High level of nitrates can cause a condition known as methemoglobinemia or "blue-baby syndrome". The EPA has set the maximum contaminant level in water at 10 mg/l. The HI97728 uses cadmium reduction method for measuring nitrate up to 30.0 mg/L (ppm) in water from 0.0 to 30.0 mg/L.
The method uses a reagent with cadmium to reduce the nitrate in the water to nitrite. In an acidic medium the nitrite ion reacts with sulfanilic acid to form a salt that reacts with other reagents to produce a colored solution that is proportional to the concentration of nitrate that was in the sample.
The HI97728 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 LED 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.
HI97728 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 comfortable in the hand for use in the field or on a table for benchtop use. The LCD is 71 mm (2.75") by 37 mm (1.6") and is backlit for easy viewing under all conditions
- LED that generates very little heat
- 8 nm narrowband interference filter that is accurate to +/- 1 nm and offers 25% increase in light efficiency.
- Reference detector that modulates the voltage to LED for consistent light output.
- A concave focusing lens that reduces errors from imperfections in the cuvette
Stable Light Source:
- The internal reference system of the HI97728 photometer compensates for any drifts due to power fluctuations or ambient temperature changes. With a stable source of light the readings are fast and stable between your blank (zero) measurement and sample measurement..
High Efficiency Light Source:
- LED light sources offer superior performance compared to tungsten lamps. LEDs have a much higher luminous efficiency, providing more light while using less power. They also produce little heat, which could otherwise affect electronic stability.
High Quality Filters:
- Improved optical filters ensure greater wavelength accuracy and allow a brighter, stronger signal to be received. The end result is higher measurement stability and less wavelength error.
Greater Light Yield:
A focusing lens collects all of the light that exits the cuvette, eliminating errors from imperfections and scratches that may be present in the glass. The use of the convex lens reduces the need for indexing cuvettes..
CAL Check Functionality:
- Hanna’s exclusive CAL Check feature allows for performance verification and calibration of the meter using NIST traceable standards. Our CAL Check standard vials are developed to simulate a specific absorbance value at each wavelength to verify the accuracy of subsequent readings.
Built-in Reaction Timer:
Waiting the proper reaction time is of key importance when performing colorimetric measurements. The countdown timer displays the time remaining until a measurement will be taken, ensuring consistent results between sample measurements and users.
Large Cuvette Size:
- The sample cell of the HI97728 fits a round, glass cuvette with a 25 mm path length. The relatively long path length of the sample cuvette allows the light to pass through more of the sample solution, ensuring accurate measurements even in low absorbance samples.
Intuitive Dot Matrix Display:
- The HI97728 is designed with a backlit, graphic LCD. With virtual keys, a battery status indicator, and error messages. Users will find the meter interface intuitive and easy to read. A dedicated help key provides information relating to the current meter operation, and can be used at any stage in the setup or measurement process to show contextual help.
The meter uses three common AA batteries that allow for about 800 measurements to be taken. The auto-off feature automatically shuts off the meter after 15 minutes of inactivity in order conserve battery life.
Nitrate Range 0.0 to 30.0 mg/L (NO3-N) Nitrate Resolution 0.1 mg/L Nitrate Accuracy ±0.5 mg/L ±10% of reading Nitrate Method Adaptation of Cadmium Reduction Method Photometer/Colorimeter Light Source Light emitting diode Photometer/Colorimeter Light Detector silicon photocell with narrow band interference filter @ 525 nm Bandpass Filter Bandwidth 8 nm Bandpass Filter Wavelength Accuracy ±1.0 nm Cuvette Type round, 24.6 mm diameter (22 mm inside) GLP date, time of last calibration Display 128 x 64 pixel B/W LCD with backlight Logging Type automatic logging Logging Memory 50 measurement Battery Type/Life 1.5V AA battery (3 pcs.) / > 800 measurements (without backlight) Automatic Shut-Off After 15 minutes of inactivity (30 minutes before a READ measurement) Environment 0 to 50°C (32 to 122°F); relative humidity: 100% (IP67) Weight 380 g (13.4 oz.) with batteries Dimensions 142.5 x 102.5 x 50.5 mm (5.6 x 4.0 x 2.0") Ordering Information HI97728 is supplied with cuvettes (2), caps (2), plastic inserts for cuvettes (2), 1.5V AA batteries (3), instruction manual, and instrument quality certificate. Kit : HI97728C is supplied with CAL-Check standards, cuvettes (2), caps (2), plastic inserts for cuvette, (2), scissors, cuvette cleaning cloth, 1.5V AA batteries (3), instruction manual, and instrument quality certificate Notes Primary Application: The measurement of nitrate in drinking water.