Appearance 外观 White to off-white powder 白色至类白色粉未 Specific Rotation [25/D] 旋光 -14.0 to -15.3 º Chloride (Cl) 氯 Not more than 0.10% 不高于0.10% Heavy Metals (Pb) 重金属（以铅计） Not more than 10 ppm 不高于10ppm Ammonium (NH4) 铵 Not more than 0.02% 不高于0.02% Iron (Fe) 铁 Not more than10ppm 不高于10ppm Sulfate (SO4) 硫化物 Not more than 0.02% 不高于0.02% Other amino acid 其它氨基酸 Not more than 0.5% 不高于0.5% Loss on Drying 干燥失重 Not more than 0.20% 不高于0.20% Residue on Ignition (Sulfated) 灼烧残渣 Not more than 0.2% 不高于0.20% Assay 含量 98.5 to 101.0%