项目Item                                                         优级纯   分析纯   化学纯
                                                                         (GR)     (AR)    (CP)
含量(C₂H₂O₄·
2H₂O)Assay,%                                              ≥99.8     99.5     99.5
澄清度试验Clarity                                             合格     合格     合格
水不溶物Insoluble matter in water,%            ≤0.002    0.005    0.01
灼烧残渣（以硫酸盐计）Ignition residue,%≤0.01     0.02     0.05
氯化钠(Cl)Chloride,%                                    ≤0.0005   0.002    0.005
硫酸盐(SO₄)Sulfate,%                                   ≤0.001    0.002    0.005
总氮量(N)Total nitrogen,%                            ≤0.001    0.002    0.005
钙(Ca)Calcium,%                                          ≤0.001    0.003    0.005
铁(Fe)Iron,%                                                 ≤0.0002   0.0005   0.002
重金属(以Pb计)Heavy metals,%                  ≤0.0002   0.0004   0.001
易碳化物质Readily carboniz-able substance      合格     合格     合格