Ammonium nitrogen, determination

Drolc, A., Ros, M., and Cotman, M. (2004), Establishment of traceability of ammonium nitrogen determination in wastewater, Anal. Bioanal. Chem., 378,1243-1250. 

Selmer and Sorenson [52] have described a procedure for extraction of ammonium from seawater for 15N determinations. In this method ammonium nitrogen was converted to indophenol and concentrated onto an octadecylsi-... 

Marsh et al. [47] have described an apparatus based on an autoanalyser system for the automatic preparation of soil extracts for mineral nitrogen determination. It consists of a reagent adder, which adds the correct volume of extractant for an approximately weighed amount of soil, and a sample preparation unit, which mixes, filters, dilutes and loads samples on to an autoanalyser sampler. A labour saving of 60% is achieved in this method compared to manual method. Examples are given of the determination of nitrate plus nitrate nitrogen and ammonium nitrogen. 

Table 12.8 Determination of ammonium-nitrogen in soil after extraction by manual and automatic techniques... 

Discussion 5.6. Determination of organic pius ammonium nitrogen... 

Heat the flask gently until frothing ceases, more strongly until the solution clears, and then for a further 1 h with the sulphuric acid condensing in the lower part of the neck of the flask. Allow to cool, carefully add approximately 100 ml of water and warm to dissolve the soluble material. When cool, transfer quantitatively into a 250-ml volumetric flask and dilute to 250 ml. Retain the diluted digest for the determination of ammonium nitrogen. 

International Standard Organization. 1984. Water quality. Determination of ammonium nitrogen. Distillation and titrimetric method. ISO 5664. International Organization for Standardization, Case Postale 56, CH-1211, Geneva 20 Switzerland. 

Dudek, N., Brzezinski, M. A., and Wheeler, P. A. (1986). Recovery of ammonium nitrogen by solvent extraction for the determination of relative abundance in regeneration experiments. Mar. Chem. 18, 59-69. 

ISO 14255 1998 Soil quality - Determination of nitrate nitrogen, ammonium nitrogen and total soluble nitrogen in air-dry soils using calcium chloride solution as extractant. 

For the determination of ammonium nitrogen, ion-selective electrodes are increasingly used [3, 25, 26]. 

For the gas-diffusion spectrophotometric determination of carbonate, sulfide, sulfite and ammonium nitrogen, the volatile compounds generated under suitable pH conditions penetrate the membrane in a gas-diffusion separator and are collected in acceptor streams containing the appropriate chromogenic reagents. When the separation process is sufficiently selective, the determination may be based on a protolytic reaction, with the... 

An MCFIA system exploiting a gas diffusion device has been developed for the spectrophotometric determination of ammonium nitrogen in surface and tap waters as well as sea and estuarine waters (Figure 7.41). The efficiency of complexing agents to prevent precipitation of metallic hydroxides, due... 

I. Lukkari, J. Ruzicka, G.D. Christian, Determination of total ammonium-nitrogen and free ammonia in a fermentation medium by sequential injection analysis, Fresenius J. Anal. Chem. 346 (1993) 813-818. 

For nitrogen determination (ASTM D-3179 [37]), the pulverized coal is boiled in concentrated sulfuric acid containing K2SO4 and a suitable catalyst. All nitrogen is converted to ammonium sulfete and subsequently, the mixture is made alkaline by the addition of NaOH or KOH. The generated NH3 is distilled, condensed, and absorbed into boric acid, which is titrated with a standard solution. 

Ammonia may be estimated by dissolving the gas in a known volume of standard acid and then back-titrating the excess acid. In a method widely used for the determination of basic nitrogen in organic substances (the Kjeldahl method), the nitrogenous material is converted into ammonium sulphate by heating with concentrated sulphuric acid. The ammonia is then driven off by the action of alkali and absorbed in standard acid. 

As remarked on p. 214, the validity of the nonane pre-adsorption method when adsorptives other than nitrogen are employed for determination of the isotherms, has been examined by Tayyab. Two organic adsorptives, /i-hexane and carbon tetrachloride, which could be used at or near room temperature, were selected and the adsorbents were the ammonium salts of... 

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