| Synonyms | Sodium carboxymethyl cellulose, enzymatically hydrolysed |
| Definition | Enzymatically hydrolysed carboxymethylcellulose is obtained from carboxymethylcellulose by enzymatic digestion with a cellulase produced by Trichoderma longibrachiatum (formerly T. reesei) |
| Chemical name | Carboxymethyl cellulose, sodium, partially enzymatically hydrolysed |
| Chemical formula | Sodium salts of polymers containing substituted anhydroglucose units with the general formula: |
| [C6H7O2(OH)x(OCH2COONa)y]n |
| where n is the degree of polymerisation |
| x = 1,5 to 2,8 |
| y = 0,2 to 1,5 |
| x + y = 3,0 |
| (y = degree of substitution) |
| Formula weight | 178,14 where y = 0,2 |
| 282,18 where y = 1,5 |
| Macromolecules: Not less than 800 (n about 4) |
| Assay | Not less than 99,5 %, including mono- and disaccharides, on the dried basis |
| Description | White or slightly yellowish or greyish, odourless, slightly hygroscopic granular or fibrous powder |
| Identification | |
A.Solubility | Soluble in water, insoluble in ethanol |
B.Foam test | Vigorously shake a 0,1 % solution of the sample. No layer of foam appears. This test distinguishes sodium carboxymethyl cellulose, whether hydrolysed or not, from other cellulose ethers and from alginates and natural gums |
C.Precipitate formation | To 5 ml of a 0,5 % solution of the sample add 5 ml of a 5 % solution of copper or aluminium sulphate. A precipitate appears. This test distinguishes sodium carboxymethyl cellulose, whether hydrolysed or not, from other cellulose ethers and from gelatine, carob bean gum and tragacanth gum |
D.Colour reaction | Add 0,5 g of the powdered sample to 50 ml of water, while stirring to produce a uniform dispersion. Continue the stirring until a clear solution is produced. Dilute 1 ml of the solution with 1 ml of water in a small test tube. Add 5 drops of 1-naphthol TS. Incline the tube, and carefully introduce down the side of the tube 2 ml of sulphuric acid so that it forms a lower layer. A red-purple colour develops at the interface |
E.Viscosity (60 % solids) | Not less than 2,5 kgm-1s-1 at 25 oC corresponding to an average molecule weight of 5 000 D |
| Purity | |
| Loss on drying | Not more than 12 % (105 oC to constant weight) |
| Degree of substitution | Not less than 0,2 and not more than 1,5 carboxymethyl groups per anhydroglucose unit on the dried basis |
| pH of a 1 % colloidal solution | Not less than 6,0 and not more than 8,5 |
| Sodium chloride and sodium glycolate | Not more than 0,5 % singly or in combination |
| Residual enzyme activity | Passes test. No change in viscosity of test solution occurs, which indicates hydrolysis of the sodium carboxymethyl cellulose |
| Lead | Not more than 3 mg/kg |
