溴甲酚绿

Bromocresol green

CAS号: 76-60-8

分子式: C21H14Br4O5S

分子量: 698.01

别名: 溴甲酚蓝；四溴间甲酚磺酚酞

白色到微黄色结晶或浅褐色粉末。易溶于醇及稀碱液，微溶于水，不溶于醚及苯；其钠盐能溶于水。内酯型为无色，醌型为砖红色无定型水合物。各文献报告色泽不一。熔点225℃(内酯型)。
密度：0.79
0.1%的溴甲酚绿-乙醇溶液： ***溴甲酚绿指示液（1g/L）配制：称取0.1克溴甲酚绿，溶解在20毫升无水酒精里，加水稀释到100克（粗略一点，100毫升也行），配好后 ,检测pH变换范围 (yellow)3.8 to 5.4(blue) 就可。 ***溴甲酚绿-甲基红指示液配制：将溴甲酚绿乙醇溶液（1g/L）与甲基红乙醇溶液（2g/L）按3+1体积比混合，摇匀。

GB/T 15349-94
项目Item                                       分析纯
                                                (AR)
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
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


品级Grade                               ACS级  
                                (ACS reagent, Dye content 95 %)
外观Appearance                          褐色至棕色粉末
红外光谱鉴别Infrared spectrometry       Conforms
纯度Purity                              ≥95.0% (HPLC)
λ  422 - 426 nm
Extinction Coefficient                  ≥17000
  c = 0.03g/l; Acified Methanol  
Appearance (Clarity) Pass
Visual Interval                        Pass
                                       pH 3.8 Yellow
Visual Interval                        Pass
                                       pH 4.5 Green
Visual Interval                        Pass
                                       pH 5.4 Blue


品级Grade                               ACS级  

外观Appearance                         褐色至棕色粉末
红外光谱鉴别Infrared spectrometry      Conforms
Visual Interval                        Pass
                                       pH 3.8 Yellow
Visual Interval                        Pass
                                       pH 4.5 Green
Visual Interval                        Pass
                                       pH 5.4 Blue