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Prepared at the 17th JECFA (1973), published in FNP 4 (1978) and in FNP 52 (1992) |
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SYNONYMS |
INS No. 388 |
DEFINITION | |
Chemical names |
3,3'-Thiodipropionic acid, diethyl sulfide 2,2'-dicarboxylic acid, thiodihydracrylic acid, ß,ß'-thiodipropionic acid |
C.A.S. number |
111-17-1 |
Chemical formula |
C6H10O4S |
Structural formula |  |
Formula weight |
178.21 |
Assay |
Not less than 98.5% |
DESCRIPTION |
White crystalline solid having a slight characteristic odour |
FUNCTIONAL USES |
Antioxidant |
CHARACTERISTICS | |
IDENTIFICATION | |
Solubility |
Soluble in water; freely soluble in ethanol |
Melting range |
130 - 134o |
Sulfur |
Between 17.5% and 18.5% See description under TESTS |
PURITY | |
Sulfated ash |
Not more than 0.2% |
Selenium |
Not more than 30 mg/kg |
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 |
TESTS | |
| IDENTIFICATION TESTS | |
Sulfur |
Weigh 0.700 g of the sample and add 100 ml of acetic acid and 50 ml of ethanol and heat the mixture gently until the sample dissolves completely. Add 3 ml of hydrochloric acid and add 4 drops of p-ethoxychrysoidin TS and immediately titrate with 0.1 N bromide-bromate TS. As the end point is approached (pink colour) add 4 more drops of the indicator solution and continue the titration dropwise, to a colour change from red to pale yellow. Perform a blank determination and make any necessary correction. Each ml of 0.1 N bromide-bromine TS is equivalent to 1.603 mg of S. |
METHOD OF ASSAY |
Dissolve 0.350 g of the sample in 40 ml of water, add phenolphthalein TS and titrate with 0.1 N sodium hydroxide to the first apppearance of a faint pink colour that persists for at least 30 sec. Each ml of 0.1 N sodium hydroxide is equivalent to 8.910 mg of C6H10O4S. |