This part of GB/T 10209 specifies the determination of total nitrogen content for monoammonium phosphate and diammonium phosphate by titrimetric method after distillation.
It is applicable to the determination of total nitrogen content for monoammonium phosphate and diammonium phosphate produced by various processes.
2 Normative references
The following documents contain provisions which, through reference in this part of GB/T 10209, constitute provisions of this part. For dated references, subsequent amendments to (excluding correction to), or revisions of, any of these publications do not apply. However, parties to agreements based on this part are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. For undated references, the latest editions apply to this part.
GB/T 2441.1-2008 Determination of urea - Part 1: Total nitrogen content
HG/T 2843 Chemical fertilizer products - Standard volumetric, standard, reagent and indicator solutions for chemical analysis
3 Principle
Distill ammonia from alkaline solution, absorb it by excess sulfuric acid solution, and conduct back titration with sodium hydroxide standard volumetric solution in the presence of methyl red-methylene blue mixed indicator solution.
