COMMISSION REGULATION (EU) No 231/2012 of 9 March 2012
Synonyms
Cellulose gel
Definition
Microcrystalline cellulose is purified, partially depolymerised cellulose prepared by treating alpha-cellulose, obtained as a pulp from strains of fibrous plant material, with mineral acids. The degree of polymerisation is typically less than 400
Einecs: 232-674-9
Chemical name: Cellulose
Chemical formula: (C 6 H 10 O 5 ) n
Molecular weight: About 36 000
Assay: Not less than 97 % calculated as cellulose on the anhydrous basis
Particle size: Not less than 5 μm (not more than 10 % of particles of less than 5 μm)
Description
A fine white or almost white odourless powder
Identification
Solubility: Insoluble in water, ethanol, ether and dilute mineral acids. Slightly soluble in sodium hydroxide solution
Colour reaction: To 1 mg of the sample, add 1 ml of phosphoric acid and heat on a water bath for 30 minutes. Add 4 ml of a 1 in 4 solution of pyrocatechol in phosphoric acid and heat for 30 minutes. A red colour is produced
Infrared absorption spectroscopy:To be identified
Suspension test: Mix 30 g of the sample with 270 ml of water in a high-speed (12 000 rpm) power blender for 5 minutes. The resultant mixture will be either a free-following suspension or a heavy, lumpy suspension which flows poorly, if at all, settles only slightly and contains many trapped air bubbles. If a free-flowing suspension is obtained, transfer 100 ml into a 100-ml graduated cylinder and allow to stand for 1 hour. The solids settles and a supernatant liquid appears
pH: The pH of the supernatant liquid is between 5,0 and 7,5 (10 % suspension in water)
Purity
Loss on drying: Not more than 7 % (105 °C, 3 hours)
Water soluble matter: Not more than 0,24 %
Sulphated ash: Not more than 0,5 % (800 ± 25 °C)
Starch: Not detectable. To 20 ml of the dispersion obtained in Identification, suspension test, add a few drops of iodine solution and mix. No purplish to blue or blue colour should be produced
Carboxyl groups: Not more than 1 %
Arsenic: Not more than 3 mg/kg
Lead: Not more than 2 mg/kg
Mercury: Not more than 1 mg/kg
Cadmium: Not more than 1 mg/kg