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DL-TARTARIC ACID

 

Prepared at the 53rd JECFA (1999) and published in FNP 52 Add 7 (1999), superseding specifications prepared at the 21st JECFA (1977), published in NMRS 57 (1977) and in FNP 52 (1992). No ADI allocated at the 21st JECFA in 1977.

SYNONYMS

dl-Tartaric acid

DEFINITION

 

Chemical names

DL-Tartaric acid, 2,3-dihydroxybutanedioic acid; 2,3-dihydroxysuccinic acid

C.A.S. number

133-37-9

Chemical formula

C4H6O6

Structural formula

 

Formula weight

150.09

Assay

Not less than 99.5% on the dried basis

DESCRIPTION

Colourless or translucent crystals, or a white crystalline powder; odourless

FUNCTIONAL USES

Synergist for antioxidants, acid, emulsifier, sequestrant, flavouring agent (see "Table of specifications of flavouring agents")

CHARACTERISTICS

 

IDENTIFICATION

 

Solubility (FNP 5)

Freely soluble in water; sparingly soluble in ethanol

Optical rotation (FNP 5)

A 1 in 10 solution has no optical activity

Test for tartrate (FNP 5)

Passes test

PURITY

 

Loss on drying (FNP 5)

Not more than 0.5% (over P2O5, 3 h)

Melting range (FNP 5)

200 - 206 with decomposition when heated rapidly in a sealed capillary-tube

Sulfated ash (FNP 5)

Not more than 0.1%

Readily oxidizable substances

Dissolve 1 g of the sample in 25 ml dilute sulfuric acid TS. Add 4 ml of 0.1 N potassium permanganate while keeping the solution at 20. The colour of the solution does not disappear within 3 min.

Sulfates (FNP 5)

Not more than 0.05%
0.4 g of the sample meets the requirements of the Limit Test, using 0.5 ml of 0.01 N sulfuric acid in the control

Lead (FNP 5)

Not more than 2 mg/kg
Prepare a sample solution as directed for organic compounds in the Limit Test and determine the lead content by atomic absorption spectroscopy (FNP 5).

METHOD OF ASSAY

Weigh accurately about 2 g of the dried sample, dissolve it in 40 ml of water, add phenolphthalein TS, and titrate with 1 N sodium hydroxide. Each ml of 1 N sodium hydroxide is equivalent to 75.04 mg of C4H6O6.

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