COMMISSION REGULATION (EU) No 231/2012 of 9 March 2012
Synonyms
Cross-linked carboxymethyl cellulose; Cross-linked CMC; Cross-linked sodium CMC;
Definition
Cross-linked sodium carboxymethyl cellulose is the sodium salt of thermally cross-linked partly O-carboxymethylated cellulose
Einecs:
Chemical name: Sodium salt of the cross-linked carboxymethyl ether cellulose
Chemical formula: The polymers containing substituted anhydroglucose units with the general formula:
C 6 H 7 O 2 (OR 1 )(OR 2 )(OR 3 ) where R 1 , R 2 and R 3 may be any of the following:
— H
— CH 2 COONa
— CH 2 COOH
Molecular weight:
Assay:
Description
Slightly hygroscopic, white to off white, odourless powder
Identification
Precipitate formation: Shake 1 g with 100 ml of a solution containing 4 mg/kg methylene blue and allow to settle. The substance to be examined absorbs the methylene blue and settles as a blue, fibrous mass
Colour reaction: Shake 1 g with 50 ml of water. Transfer 1 ml of the mixture to a test tube, add 1 ml water and 0,05 ml of freshly prepared 40 g/l solution of alpha-naphthol in methanol. Incline the test tube and add carefully 2 ml of sulphuric acid down the side so that it forms a lower layer. A reddish-violet colour develops at the interface
Test for sodium: Passes test
pH: Not less than 5,0 and not more than 7,0 (1 % solution)
Purity
Loss on drying: Not more than 6 % (105 °C, 3 hours)
Water soluble matter: Not more than 10 %
Degree of substitution: Not less than 0,2 and not more than 1,5 carboxymethyl groups per anhydroglucose unit
Sodium content: Not more than 12,4 % on anhydrous basis
Arsenic: Not more than 3 mg/kg
Lead: Not more than 2 mg/kg
Cadmium: Not more than 1 mg/kg
Mercury: Not more than 1 mg/kg