Nitrogen determination method
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Let’s discuss the methods for nitrogen testing, including ammonia, nitrate, organic matter, as well as those cases where the concentration is low; we will also explore the differences and reasons regarding the digestion methods, catalysts, distillation equipment, and absorption solutions used for various types of samples.
Use that semi-automatic Kjeldahl nitrogen analyzer
Gentlemen, please explain in detail – mainly the differences and why, not so briefly!
Check the national standards; it’s all specified there
I work in wastewater testing; I’ve been in this field for only half a year. Now I’m dealing with statistical tasks, so if my explanations aren’t good enough, I hope experts can give me some guidance. In organic analysis, volatilization and distillation separation methods are commonly used; for example, in the determination of elements such as C, H, O, N, and S. Whether it is the determination of nitrogen in organic or inorganic substances, the nitrogen in the compound is first converted into ammonia through certain treatment, then into ammonia gas in the presence of strong alkalis, and finally absorbed by sulfuric acid. Another method for determining nitrogen involves the formation of corresponding weak bases from formaldehyde and ammonium salts under neutral conditions. Titrated with hydrochloric acid.
To correct this: In organic analysis, volatilization and distillation methods are commonly used for separation; for example, in the determination of elements such as C, H, O, N, and S. Whether it is the determination of nitrogen in organic or inorganic substances, the nitrogen in the compound is first converted into ammonia through certain treatment, and then into ammonia gas in the presence of strong alkalis. Finally, it is absorbed using boric acid. It’s not sulfuric acid; titration is carried out using 0.02 mol/L sulfuric acid.
The measurement of elements is generally carried out indirectly by converting them into some substance that is easier to measure through chemical reactions
I’m not quite sure what you mean by the second part of your sentence. Could you give some suggestions regarding nitrogen testing? You can use TPD-MS for this purpose: heat the sample gradually, and use mass spectrometry to determine the nitrogen content.
The topic raised by the original poster is quite extensive; it’s enough to justify a review of tens of thousands of words. If one wants a comprehensive understanding of the various forms of nitrogen present in water, it would be advisable to read carefully the book \"Methods for the Monitoring and Analysis of Water and Wastewater\", compiled by the Environmental Protection Administration.