Gold Number is a term used in colloidal chemistry. It is defined as the minimum amount of lyophilic colloid in milligrams which prevents the flocculation of 10mlgold sol by the addition of 1 ml of 10%NaCl solution.
Coagulation of gold sol is indicated by colour change from red to blue when particle size just increases. More is the gold number less is the protective power of the lyophilic colloid since it means that the amount required is more.It was first used by Zsigmondy.The amount is taken in terms of weight in milligrams.
The gold number of some colloids is given below.
| Protective Colloids | Gold Number |
|---|---|
| Gelatin | 0.005-.01 |
| Haemoglobin | 0.03-0.07 |
| Egg Albumin | 0.15-0.25 |
| Potato Starch | 25 |
| Gum arabic | 0.15-0.25 |
| Caseinate | 0.01 |
| Sodium Oleate | 1-5 |
| Dextrin | 6-20 |
No comments:
Post a Comment