| Property | Specification | Test Method |
|---|---|---|
| Appearance | White crystals or granules | Visual |
| Assay (as C₆H₈O₇·H₂O) | Typically 99.0% – 100.5% (anhydrous) or 99.5% – 101.0% (monohydrate) | Titrimetry |
| Water Content | <= 0.5% (anhydrous) or ~8.0% (monohydrate) | Karl Fischer Titration |
| pH (of a 10% solution) | 3.0 – 3.5 | Potentiometr |
| Loss on Drying | <= 0.1% | Gravimetry |
| Sulfate (as SO₄) | <= 0.015% | Ion Chromatography |
| Chloride (as Cl) | <= 0.001% | Ion Chromatography |
| Insoluble Matter | <= 0.005% | Gravimetry |
| Oxalic Acid | <= 0.036% | Titrimetry |
| Heavy Metals (as Pb) | <= 1 ppm | Atomic Absorption Spectroscopy (AAS) |
| Arsenic (as As) | <= 1 ppm (may not be included in all COA reports) | Inductively Coupled Plasma Mass Spectrometry (ICP-MS) |
