A standard reference material for the measurement of particle mobility by electrophoretic light scattering

摘要

A standard reference material (SRM) was developed for the calibration and evaluation of light scattering equipment used to measure electrophoretic mobility. SRM 1980 is a positive mobility standard containing 500 mg dm~(-3) microcrystalline goethite (α-FeOOH) and 100 μmol g~(-1) phosphate in 0.05 mol dm~(-3) sodium perchlorate electrolyte solution at pH 2.5. The suspension is diluted prior to use. A certified mobility value (2.53 ± 0.12 μm cm V~(-1) s~(-1)) was determined from a statistical analysis of round robin data from five laboratories according to NIST guidelines. This paper documents the development, characterization and evaluation of this material. Also discussed are the various contributions to measurement uncertainty and inconsistency, and appropriate protocols for dealing with these problems.