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HomePhotometry & ReflectometryPhotometric Determination of Ammonium in Manure

Photometric Determination of Ammonium in Manure using Indophenol Blue

Abstract

This protocol describes the photometric determination of ammonium in manure using the indophenol blue method, utiliizing Spectroquant® test kits. Ammonium is extracted and made to react with hypochlorite ions in an alkaline solution and phenol to produce a blue indophenol derivative. This procedure allows for the accurate assessment of ammonium levels for agricultural applications.

Section Overview:

three models of Spectroquant® spectrophotometers: Prove 100 plus, Prove 300 plus, and Prove 600 plus. Each device has a sleek, modern design with a rectangular body. The largest model in the foreground, Prove 600 plus, is green with a black top and features a touchscreen interface displaying measurement data, as well as a slot for sample insertion. The top right corner of the device has a yellow "M" logo and "600+" printed in bold yellow on the front corner. Two smaller models, Prove 100 plus and Prove 300 plus, are placed in the background. Prove 100 plus is light green with a black top, while Prove 300 plus is yellow with a black top. Both also feature touchscreens and the "M" logo.

Spectroquant® spectrophotometers - Prove 100 plus, Prove 300 plus, & Prove 600 plus

Introduction

Ammonium (NH4+) is one of the most important sources of nitrogen for plant nutrition and it is formed with the mineralization of decomposed organic matter1. Research also has established that ammonium is the naturally preferred source of nitrogen for plant growth2. With increasing demand for organic food products globally, farmers are resorting to the use of compost and manure. While ready-made ammonium fertilizers have defined concentration of the cation and related compounds in them, it is important to analyze composts and manure for their accurate concentration of ammonium. For, early phases of decomposition accounts for loss of nitrogen as ammonia, and there is natural loss of ammonium as the compost manure matures3. Excess ammonium has also been reported to be toxic in higher plants4.

This application note details a photometric ammonium test method for manure samples, using the indophenol blue method. Post the sample extraction and in a strongly alkaline solution, ammonium nitrogen is present almost entirely as ammonia, which reacts with hypochlorite ions to form monochloramine. This in turn reacts with a phenol compound to form a blue indophenol derivative that is determined photometrically.

Reagents, Instruments and Materials

Ammonium Test Kits/Reagents

For the measurement, one of the following Spectroquant® test kits is necessary:

  • Spectroquant® Ammonium Cell Test (1.14544)*
  • Spectroquant® Ammonium Cell Test (1.14559)
  • Spectroquant® Ammonium Test (1.14752)
  • Spectroquant® Ammonium Test (1.00683)

*not compatible with Move 100

Instrument(s) & Devices

For the measurement, one of the following Spectroquant® photometers is necessary:

  • Spectroquant® VIS Spectrophotometer Prove 100 Plus (1.73026)
  • Spectroquant® UV/VIS Spectrophotometer Prove 300 Plus (1.73027)
  • Spectroquant® UV/VIS Spectrophotometer Prove 600 Plus (1.73028)
  • Spectroquant® Colorimeter Move 100 (1.73632)

Also, legacy systems

  • Spectroquant® Spectrophotometer Prove 100/300/600
  • Spectroquant® Photometer NOVA 30/60/60A

Software for Data transfer

  • Optional Spectroquant® Prove Connect to LIMS software package (Y.11086) to transfer your data into an existing LIMS system.

Instrument Accessories

  • Rectangular cells 10 mm (1.14946) and/or
  • Rectangular cells 20 mm (1.14947) and/or
  • Rectangular cells 50 mm (1.14944)

Other Reagents and Accessories

  • Water for analysis (1.16754)
  • Membrane filter with 0.45 µm pore diameter
  • Folded filter

Experimental Procedure

Sample Preparation

  • Put 10 mL of the sample into a 1000 mL volumetric flask, fill up to volume with water for analysis, and mix.
  • After the solid parts have settled, take 10 mL of the supernatant solution and, mixed with a spatula–tip full of charcoal activated for soil tests, put it into a 50 mL volumetric flask and fill up to volume with water for analysis.
  • Before determination filter the charcoal through a folded filter. In case the solution remains cloudy, filter again through a membrane filter.

Analysis

Determine with one of the above-mentioned test kits.

Calculation

Ammonium content in mg/kg NH4+ = analysis value in mg/L NH4+ x 2000

See more applications for photometry at Protocols and Application Notes

Related Products
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References

1.
Zhang W, Zhang R, Yang Y, Huang T, Wen G. Removal of High Concentrations of Ammonium from Groundwater in a Pilot-Scale System through Aeration at the Bottom Layer of a Chemical Catalytic Oxidation Filter. IJERPH. 16(20):3989. https://doi.org/10.3390/ijerph16203989
2.
2011 Jun 27. Guidelines for drinking-water quality, 4th edition, pp. 398–403. [Internet]. Who.int. Available from: https://www.who.int/publications/i/item/9789241548151
3.
2024 Mar 26 . Compost interpretation. [Internet]. Clemson.edu.[cited 07 Aug 2024]. Available from: https://www.clemson.edu/public/regulatory/ag-srvc-lab/compost/interpretation
4.
Britto DT, Kronzucker HJ. 2002. NH4+ toxicity in higher plants: a critical review. Journal of Plant Physiology. 159(6):567-584. https://doi.org/10.1078/0176-1617-0774
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