SODIUM POLYPHOSPHATES, GLASSY
Prepared at the 46th JECFA (1996), published in FNP 52 Add 4 (1996) superseding specifications prepared by the 20th JECFA (1976), published in FNS 1B (1977) and in FNP 52 (1992). Metals and arsenic specifications revised at the 55th JECFA (2000). A group MTDI of 70 mg/kg bw, as
phosphorus from all food sources, was established at the 26th JECFA (1982)
SYNONYMS Sodium hexametaphosphate, sodium tetrapolyphosphate, Graham's salt; INS No 452(i)
DEFINITION Obtained by fusion and subsequent chilling of sodium orthophosphates; a class of compounds consisting of several amorphous, water-soluble polyphosphates composed of linear chains of metaphosphate units, (NaPO3)
x where x=2, terminated by Na2PO4 groups; usually identified by their Na2O/P2O5 ratio or their P2O5 content. The Na2O/P2O5 ratios vary from
about 1.3 for sodium tetrapolyphosphate, where x = approximately 4; to
about 1.1 for Graham's salt, commonly called sodium hexametaphosphate,
where x = 13 to 18; and to about 1.0 for the higher molecular weight sodium polyphosphates, where x = 20 to 100 or more. The pH of their solutions
varies from about 3 to 9.
Chemical names Sodium tetrapolyphosphate, sodium hexametaphosphate, sodium polyphosphate
C.A.S. number 68915-31-1, 10124-56-8, 10361-03-2
Assay Not less than 60.0% and not more than 71.0% of P2O5
DESCRIPTION Colourless or white, transparent platelets, granules, or powders
FUNCTIONAL USESEmulsifier, sequestrant, texturizer
