Development of Zeta Potential Reference Materials of Silica Colloid

The accurate measurement of Zeta potential is of great significance for quality control of products in various fields such as biomedicine, industrial production, environmental engineering, and food manufacturing. At present, the research on Zeta potential reference materials in China is still blank. In response to this situation, in this work three zeta potential reference materials of silica colloid were developed. Firstly, reference material candidate meeting the requirements was selected, it was silica hollow particle dispersion colloid with mass content of 2.5%, central particle size of about 80 nm and no precipitation within the validity period. Secondly, the homogeneity and stability of reference material were tested and performed well. Finally, the zeta potential and electrophoretic mobility were jointly determined by nine capable laboratories using electrophoretic light scattering testing method. The zeta potential of three reference materials are −48 mV, −39 mV, and −31 mV, respectively, with expanded uncertainties (k=2) of 5 mV, 4 mV, and 3 mV, respectively; The electrophoretic migration rates are −3.7 × 10⁻⁸ m²V⁻¹s⁻¹, −3.0 × 10⁻⁸ m²V⁻¹s⁻¹, and −2.4 × 10⁻⁸ m²V⁻¹s⁻¹, respectively, with expanded uncertainties (k=2) of 0.4×10⁻⁸ m²V⁻¹s⁻¹, 0.3×10⁻⁸ m²V⁻¹s⁻¹ and 0.3×10⁻⁸ m²V⁻¹s⁻¹, respectively. The reference materials can meet the calibration verification requirements of Zeta potential analyzers in the quantitative analysis process, and provide value guarantee for the analysis of colloidal system stability in scientific research and industry in China.