项目Item                                                                  分析纯

•                                                                                 (AR)
  
• 质量吸收系数Absorbance,L/cm·g
  
•     α1(λ1,pH 3.8,干样)                                           24-28
  
•     α2(λ2,pH 5.4,干样)                                           53-58
  
• 乙醇溶解试验Solubility in ethanol                      合格
  
• 干燥失重Drying loss,%                                       ≤3.0
  
• 灼烧残渣(以硫酸盐计)Ignition residue,%         ≤0.25
  
• 变色域Visual transition interval        　             3.8(黄绿)～5.4(蓝)
  
• 最大吸收波长(nm)Wave length of
  
• max absorbance
  
•     λ1 (pH 3.8)                                                       440-445
  
•     λ2 (pH 5.4)                                                       615-618

• 指示剂，但pH=3.8时呈黄色，pH=5.4时呈蓝绿色，pH=4.5时开始有颜色的明显变化。