The HI96728 Nitrate Portable Photometer combines accuracy and ease of use in an ergonomic, portable design. A user can accurately determine the concentration of nitrate as nitrogen in samples within a 0.0 to 30.0 mg/L (ppm) range using the HI93728-01 ready made reagents. The HI96728 offers many advanced features including the exclusive CAL Check™ function used for performance verification and calibration of the meter.
The HI96728 portable photometer is for the measurement of nitrate as nitrogen. Hanna's portable photometers feature an advanced optical system; the combination of a special tungsten lamp, a narrow band interference filter, and silicon photodetector ensure accurate photometric readings every time. The Hanna exclusive CAL Check™ feature utilizes ready-made, NIST traceable standards to verify both meter validation and calibration. The exclusive cuvette locking system ensures that the cuvette is inserted into the measurement cell in the same position every time to maintain a consistent path length.
CAL Check™ - Allows for performance verification and calibration of the meter using NIST traceable standards.
GLP - Review of the last calibration date
Auto-shut off - Automatic shut off after 10 minutes of non-use when the meter is in measurement mode. Prevents wastage of batteries in the event the meter is accidentally not turned off.
Battery status indicator - Indicates the amount of battery life left.
Built in timer - Display of time remaining before a measurement is taken. Ensures that all readings are taken at the appropriate reaction intervals for the test being performed.
Error messages - Messages on display alerting to problems including no cap, high zero, and standard to low.
Cooling lamp indicator - To maintain the desirable wavelength to be used for absorbance it is necessary to ensure component are not overheated from the heat generated by the tungsten lamp. Each photometer is designed to allow a minimal amount of time for components to cool. The cooling lamp indicator is displayed prior to a reading being taken.
Units of measure - Appropriate unit of measure is displayed along with reading.
Nitrogen is abundant in the Earth’s atmosphere and is present in water in the form of nitrate, nitrite, and ammonia. Plants use nitrogen as a nutrient to build proteins by tracking it in through their root system. Nitrate is formed in water mainly through rainfall, decomposition of organic matter, and runoff from manmade pollutants such as sewage waste and fertilizers. Almost all surface waters have a measurable level of nitrate, and a moderate amount is considered beneficial. Large amounts of nitrate, however, can lead to eutrophication which may result in decreased levels of dissolved oxygen in the water.
The HI96728 uses an adaptation of the cadmium reduction method to measure nitrate concentrations of less than 30.0 mg/L (ppm) as nitrogen. When the reagent is added to samples containing nitrate, the sample will turn an amber hue; the greater the concentration, the deeper the color. 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 nitrate determination, a narrow band interference filter at 525 nm (green) allows only green light to be detected by the silicon photodetector and omits all other visible light emitted from the tungsten lamp. As the change in color of the reacted sample increases, absorbance of the specific wavelength of light also increases, while transmittance decreases.