Ammonia is a common byproduct from the breakdown of proteins and is excreted by animals as ammonia, urea or uric acid. Ammonia is also a commonly found in fertilizer and used as a nitrogen source for plant growth. It is effective in cleaning chemical and can be found in glass and floor cleaners. Ammonia exists in two forms. One is the ionized form ammonium (NH4+) and the other is the gaseous form ammonia (NH3). The relationship in which form is present is based on the pH of the solution with ammonium becoming more predominate at pH’s less than 8. Since most naturally occurring water is pH 8 or less, ammonium is the most common form present. For aquatic life, as the pH increases this can be lethal as the ammonium is converted to ammonia, which is more toxic since it can diffuse back into the animal. In surface and groundwater, unless there is some contamination, the concentration is very low. In drinking water it is common to add ammonia to water at concentrations less than 0.4 mg/L to extend the effectiveness of chlorine as a disinfecting agent. Using the Nessler method the HI 97700 is designed to measure ammonia in the low range at levels from 0 to 3.00 mg/L ammonia – nitrogen. The results can be displayed as ammonia or ammonium as well.
The HI97700 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.
HI97700 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
Advanced features including CAL-Check to verify performance, GLP for last calibration date, setup options and the ability to see all accessories used with the meter.
When enabled, the tutorial mode will guide the user step by step through the measurement process .
Results can be displayed in multiple chemical forms
Stable Light Source:
- The internal reference system of the HI97700 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.
Mulitple Measurement Methods:
- Users can select the use of powder reagents supplied in packets or the use of low cost liquid reagents supplied in a dropper bottle.
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 HI97700 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 HI97700 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.