Item	35%	50%
Purity(m/m) %	≥ 35	≥ 50
Free acid as H2SO4 (m/m) %	≤ 0.04	≤ 0.02
Evaporation residue(m/m)%	≥ 0.08	≤ 0.06
Stability %	≥ 97.	≥ 99
Totalcarbon(as C)(m/m)%	≤ 0.03	≤ 0.01
Nitrate(As NO3 )(m/m)%	≤ 0.02	≤ 0.01