Seeking the calibration method for ammonia nitrogen standard solution
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What is the calibration method for the standard solution of ammonia nitrogen specified in GBZ/T 160.29-2004 (Determination of toxic substances in workplace air – Inorganic nitrogen compounds)? The ammonia nitrogen standard solution is prepared using sulfuric acid; there is only information on the preparation method, but no information on the calibration method. I would appreciate it if some teacher could explain how to carry out the calibration
This post was last edited by qugd on 2018-1-3 at 13:19. Since a standard solution has already been prepared using sulfuric acid, the ammonia nitrogen content can certainly be determined using acid-base titration. By utilizing the property of forming hexamethylenetetrammonium salts with an excess of formaldehyde and ammonia, the basicity of ammonia is increased to some extent; titration can then be carried out using a standard acid. This reaction is based on equivalent calculations, that is, one hydrogen atom neutralizes one ammonia molecule. This method is described in detail in many basic textbooks on analytical chemistry or analytical methods. As a basic standard solution, the ammonia nitrogen concentration of sulfuric acid an should not be lower than 1000 mg/L; thinner standard solutions can be appropriately diluted.
This post was last edited by sunshineda_VGMP on 2019-1-4 at 09:15. Is the original poster trying to determine whether the ammonia nitrogen standard solution they prepared is reliable? A more reliable and conventional method would be to use a potentiometric titrator for the titration as mentioned above. Additionally, it’s possible to use an ammonia nitrogen detector to measure the concentration of the standard solution prepared by the user and compare it with the desired standard value; of course, due to the design and performance of the instruments, there may be slight errors within a certain range.