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Prepared at the 41st JECFA (1993), published in FNP 52 Add 2 (1993) superseding specifications prepared at the 18th JECFA (1974), published in NMRS 54B (1975) and in FNP 52 (1992) |
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SYNONYMS |
Sodium 5'-inosinate, sodium inosinate, IMP, INS No. 631 |
DEFINITION | |
Chemical names |
Disodium inosine-5'-monophosphate |
C.A.S. number |
4691-65-0 |
Chemical formula |
C10H11N4Na2O8P · x H2O (x = approximately 7) |
Structural formula |  |
Formula weight |
392.17 (anhydrous) |
Assay |
Not less than 97.0% and not more than 102.0% on the anhydrous basis |
DESCRIPTION |
Odourless, colourless or white crystals, or a white crystalline powder |
FUNCTIONAL USES |
Flavour enhancer |
CHARACTERISTICS | |
IDENTIFICATION | |
Solubility |
Soluble in water, sparingly soluble in ethanol, practically insoluble in ether |
Spectrophotometry |
A 1 in 50,000 solution of the sample in 0.01 N hydrochloric acid exhibits an absorbance maximum at 250±2nm. The ratio A250/A260 is between 1.55 and 1.65, and the ratio A280/260 is between 0.20 and 0.30. |
Test for sodium |
Passes test |
Test for ribose |
Passes test |
Test for organic phosphate |
Passes test Test 5 ml of a 1 in 20 soln
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PURITY | |
Water |
Not more than 29% (Karl Fischer Method) |
pH |
7.0 - 8.5 (1 in 20 soln) |
Amino acids |
Not detectable by the following test: To 5 ml of a 1 in 1,000 solution add 1 ml of ninhydrin TS and heat for 3 min. No colour is produced. |
Related foreign substances |
Chromatographically not detectable Test 1 µl of a 1 in 200 soln |
Arsenic |
Not more than 3 mg/kg (Method II) |
Lead |
Not more than 10 mg/kg |
Heavy metals |
Not more than 20 mg/kg Test 1 g of the sample as directed in the Limit Test (Method II) |
METHOD OF ASSAY |
Weigh accurately about 500 mg of the sample, dissolve in and make to 1,000 ml with 0.01 N hydrochloric acid. Take 10.0 ml of this solution and dilute with 0.01 N hydrochloric acid to 250 ml. Determine the absorbance A of the solution in a 1-cm cell at the wave length of 250 nm using 0.01 N hydrochloric acid as the reference blank. Calculate the content of C10H11N4Na2O8P, in % in the sample by the formula:
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