This Standard Reference Material (SRM) is intended for use in the evaluation of equipment, and the validation of methodology used to measure electrophoretic mobility.

• Packaging of 500 mg/L

A unit of SRM 1980 consists of a single 60 cm³ polyethylene bottle containing 40 cm³ of suspension, which is to be diluted prior to analysis. The suspension consists of 500 mg/l goethite (a-FeOOH) suspension saturated with 100 μmol/g phosphate in a 5×10⁻² mol/L sodium perchlorate electrolyte solution at a pH of 2,5.

The goethite powder consists of acicular particles with an average dimension of 60×20 nm as determined from electron microscopy.