This part of GB/T 10209 specifies the determination of the phosphorus content of monoammonium phosphate and diammonium phosphate.
This part is applicable to the determination of water-soluble phosphorus and available phosphorus contents of 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 normative documents indicated below. For undated references, the latest edition of the normative document applies.
HG/T 2843 Chemical fertilizer products - Standard volumetric, standard, reagent and indicator solutions for chemical analysis
3 Principle
After extracting the water-soluble phosphorus and available phosphorus from the monoammonium phosphate and diammonium phosphate with water and ethylenediamine tetraacetic acid disodium solution, the orthophosphoric ions in the extracting solution will react with the quimociac reagent in acidic medium and produce yellow quinoline phosphomolybdate precipitates, then the contents of water-soluble phosphorus and available phosphorus are determined respectively with the quinoline phosphomolybdate gravimetric method (arbitration method) or quinoline phosphomolybdate volumetric method.
