Table 1.
Colloidal polystyrene and silica reference and test materials used during method validation, and their relevant properties.
| Material | Type | Dispersant | Nominal Particle Diameter (nm) | Reference Zeta Potential (mV) 1 | Mass Fraction (g/kg) | Metrological Status |
|---|---|---|---|---|---|---|
| DTS 1235 | PS | NDA, pH 9 | 300 | −42.0 ± 4.2 | 2 × 10−4 | RM |
| PS-A | PS | 10 mM NaCl | 150 | −70.3 ± 7.0 | 0.01 | RM |
| PS-B | PS | 10 mM NaCl | 150 | −70.3 ± 7.0 | 10 | RM |
| AWP4-A | SiO2 | 10 mM borate, pH 9 | 140 | N/A | 15 | Test sample |
| AWP4-B | SiO2 | 10 mM borate, pH 9 | 140 | N/A | 30 | Test sample |
| ERM-FD305 [32] | SiO2 | 10 mM borate, pH 9 | 140 | −58 ± 5 | 1.5 | CRM |
| ERM-FD306 [33] | SiO2 | 10 mM borate, pH 9 | 140 | −56 ± 4 | 22 | CRM |
1 Uncertainty value corresponds to a confidence level of approximately 95%; N/A: not available; NDA: identification and composition of buffer is subject to a non-disclosure agreement between Malvern Panalytical and the JRC; PS: polystyrene.