Appearance: Light yellow crystalline powder
Identification: Meets the requirements
Melting point: 60.0 to 62.0
Assay(HPLC): Not less than 99.0%
Loss on drying: Not more than 0.2%
Residue on ignition: Not more than 0.1%
Polymer content: Not more than 2%
Related Substance(HPLC)
6, 8-Epitrithiooctanoic acid: Not more than 0.2%
Single unknown impurity: Not more than 0.2%
Total unknown impurity: Not more than 0.5%  
Residual solvents(GC)
Toluene: Not more than 30ppm
Ethyl Acetate: Not more than 250ppm
Cyclohexane: Not more than 1000ppm