| Property | Specification | Test Method | Units |
|---|---|---|---|
| Appearance | White flakes or prills | Visual | – |
| Assay (as NaOH) | Typically Min 98.5% or Min 99.0% | Titrimetry | wt% |
| Sodium Carbonate (Na₂CO₃) | Max 0.4% – 1.0% | Gravimetry or Ion Chromatography | wt% |
| Sodium Chloride (NaCl) | Range (e.g., 6.0 – 8.0) | Potentiometry | – |
| Iron (as Fe) | Max 50 ppm – 20 ppm | Atomic Absorption Spectroscopy (AAS) | ppm |
| Mercury (as Hg) | Max 1 ppm (may not be included in all COA reports) | Cold Vapor Atomic Absorption (CVAA) | ppm |
| Loss on Drying (LOD) | Max 0.5% | Gravimetry | wt% |
