质量吸收系数Mass absorptivity,L/(cm.g)    ≥71.0
乙醇溶液试验Solubility in ethanol              合格
灼烧残渣(以硫酸盐计)Ignition residue,%    ≤0.3

品级Grade                               ACS级 
                                  (ACS reagent, 95 %)
外观Appearance                          暗绿色至棕色、红棕色粉末
红外光谱鉴别Infrared spectrometry       Conforms
染料含量Dye content,                    95%
纯度Purity                              221-224 °C 
Wavelength 595 - 599 nm
消光系数Extinction Coefficient          ≥30000
Wavelength 378 - 382 nm
消光系数Extinction Coefficient          ≥8000
Wavelength 298 - 302 nm
消光系数Extinction Coefficient          ≥12000
  c = 0.01g/l, 0.1N NaOH
变色域visual transition interval：
  acid range：                          pH 1.2 (red) to pH 2.8 (yellow)
  alkaline range：                      pH 8.0 (yellow) to pH 9.2 (blue)