Reflectometric determination after reaction with Nessler’s reagent or by using the indophenol blue method.
Nitrogen in the form of ammonium is an important nutrient to test in wastewater. If there is excessive ammonium left in treated water, it can lead to environmental problems including eutrophication— excessive growth of algae and plants—upsetting marine ecosystems.1 Thus, monitoring ammonium in wastewater is a key step. In this application note, ammonium is determined in wastewater using the Reflectroquant® system and test strips.
The test kit catalog numbers apply for the following methods:
Note: This application note pertains to RQflex® 20 and all discontinued instruments (RQflex® 10, RQflex® plus)
The sample can be analyzed in its original form.
Rinse the test vessel several times with the sample solution and fill to the 5-ml mark. Add 10 drops of reagent NH4-1 and swirl. Add 1 level blue microspoon of reagent NH4-2 and swirl again. Press the reflectometer START button and simultaneously place the test strip in the sample (20 - 30 °C) for 8 min, ensuring that both reaction zones are immersed. Allow excess liquid to run off via the long edge of the strip on to an absorbent paper towel. Measure the strip in the reflectometer. The value [mg/l] will be stored automatically. (Please refer to the RQflex® operating instructions and the instruction for use of the Reflectoquant® Ammonium Test.
Rinse the test vessel several times with the sample solution and fill to the 5-ml mark. Add 10 drops of reagent NH4-1 and swirl. Add 1 level blue microspoon of reagent NH4-2 and swirl again. Press the reflectometer START button and simultaneously place the test strip in the sample (20 - 30 °C) for 4 min, ensuring that both reaction zones are immersed. Allow excess liquid to run off via the long edge of the strip on to an absorbent paper towel. Measure the strip in the reflectometer. The value [mg/l] will be stored automatically. (Please refer to the RQflex® operating instructions and the instruction for use of the Reflectoquant® Ammonium Test.)
Rinse the test vessel several times with the pretreated sample solution and fill to the 5-ml mark. Add 10 drops of reagent NH4-1 and swirl. Press START button and simultaneously immerse both reaction zones of the test strip in the sample solution (15 - 25 °C) for approx. 2 seconds. Allow excess liquid to run off via the long edge of the strip on to an absorbent paper towel. Wait 15 seconds and then measure the strip in the reflectometer. The value [mg/l] will be stored automatically. (Please refer to the RQflex® operating instructions and the instruction for use of the Reflectoquant® Ammonium Test.)
Note: If a semi-quantitative determination is sufficient there is the possibility to use MQuant® test strips, Cat. No. 1.10024; color scale graduation 10 – 30 – 60 – 100 – 200 – 400 mg/l NH4+
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