The esterification degree ≥ 80.0% 
Insoluble ash ≤ 1.0%
Dry weight loss ≤ 20.0%
Arsenic (As) ≤  0.0002 %
Heavy metals (Pb)≤  0.002%
Lead ≤ 0.0005 %
esterification degree ≥ 80.0 %
Insoluble ash ≤  1.0%
Dry weight loss ≤  20.0%
Arsenic (As) ≤ 0.0002 %
Heavy metals (Pb)≤ 0.002%
Lead ≤  0.0005%