Characters  .
White crystal or crystalline powder.
Meet the requirement
A:
Identification
A violet-red color is produced
Gives postive reaction
B:
Infrared absorption
According with IR reference spectrum
Meets the requirement

Loss on drying≤ 0.5%
Not more than 0.5% of weight0.13%

Readily carbonizable substanceQ
No more color than M. F. Q  M. F. Q
No more color than M. F. Q

Residue on ignition≤ 0.05%
Not more than 0.05% of weight0.02%

Substances insoluble in sodium carbonate
The solution is clear
Clear

Chloride  ≤ 0.014%
Not more than 0.014%<0.014%

Sulfate  ≤ 0.04%
Not more than 0.04% <0.04%

Heavy metals≤ 10ppm
The limit is 10ug per g<10ppm

Free salicylic acid≤ 0.1%
Not more than 0.1%  <0.1%

Organic volatile impurities
Meets the requirement
Meets the requirement