purity                    ≥98%
CL                   ≤0.050%
NH4                 ≤0.020%
SO4                ≤0.030%
Fe                 ≤30ppm
Pb               ≤10ppm

As                    ≤1ppm
Other Amion Acids  negative

loss on drying               ≤0.5%
ignition residue(H2SO4)            ≤0.10%
PH                        6.0～7.0