Ammonium, determination

A cation containing solution is added before ammonium determination to release exchangeable... 

For ammonium determination, two steps of photo-oxidation are needed [21], The first one allows the measurement of TKN as shown above. Then, a second one is carried out in the presence of an oxidant solution (potassium peroxodisulphate K2S208), without buffer. In these particular conditions (acidic medium), only organic nitrogen compounds are converted into nitrate, as will be explained afterwards. 

Figure 9. Comparison of ammonium determination for industrial wastewater (reference method is capillary electrophoresis).

Table 5. Characteristics of the UV method for ammonium determination (without dilution)...

The sample is inserted simultaneously with the reagents required for a given determination thereafter, it is inserted again but with the reagents required for the second determination. In this way, sequential determinations are performed in the same manifold. This approach was exploited initially in the spectrophotometric determinations of ammonium and phosphate in plant digests [20], which required rather different reaction conditions the ammonium determination was carried out in a highly alkaline medium, whereas the phosphate determination was performed... 

M.I.G.S. Almeida, J.M. Estela, M.A. Segundo, V. Cerda, A membraneless gas-diffusion unit — multisyringe flow injection spectrophotometric method for ammonium determination in untreated environmental samples, Talanta 84 (2011) 1244. 

UOP 959-98 by ion chromatography Ammonium determination in aqueous solutions by ion NH4+ wastewater Drinking water. 

Coupling of FIA with GD is the most frequent. For example for ammonium determination several FIA—GD systems have been developed. Different detection methods coupled with GD—FIA system have been compared elsewhere [69]. Other examples are an FIA—GD system exploiting conductometric detection for Kjeldahl-produced ammonia [70], an FIA—GD system [71] applied to clinical blood samples using a bulk acoustic wave impedance sensor, a GD—FIA system using a capacitively coupled contactless conductivity detection (C4D) [72] and a GD—FIA with conductometric detection to monitor the ammonium content in open ocean seawater samples [73]. 

In Table 3.2 are shown the figures of merit of some methods developed for ammonium determination exploiting a gas diffusion ceU. These results demonstrate the various possibilities of hyphenation of gas diffusion cells with different detectors in an FIA approach, but obtaining different limits of detection (LODs) and linear working ranges. Therefore, the choice of method and detector has to be made according to those best suited to the type of samples to be analyzed. 

SIA system for ammonium determination using a gas diffusion cell. FIC holding coil IV injection valve RC reaction coil SV selection valve. 

J. Klimundova, R. Forteza, V. Cerda, A multisyringe flow injection system coupled with a gas diffusion cell for ammonium determination Int, J. Environ. Anal. Chem. 83 (2003) 233—246. 

A. Cerda, M.T. Oms, R. Forteza, V. Cerda, Evaluation of flow injection methods for ammonium determination in wastewater samples. Anal. Chim. Acta 311 (1995) 165-173. 

B.F. Reis, J.A. Vieira, F.J. Krug, M.R Gine, Development of a flow injection system with two analytical paths for ammonium determination in soil extracts by conductometry, J. Braz. Chem. Soc. 8 (1997) 523-528. 

Amides, determination of 102 Aminoacetate, determination of 234 Amino acids, determination of 124 Ammonium, determination of 43, 46,... 

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