棕色晶体(由乙醇重结晶)。为磺酞类色素。在氯化锌存在下,将邻磺基二氯苯甲酸与对二甲酚加热制取。有两种变色范围：pH值1.2～2.8红～黄；pH值8.0～9.6黄一蓝。
熔点  212°C (dec.) 
Merck  14,10083 
BRN  363132 
CAS DataBase Reference 125-31-5(CAS DataBase Reference) 

BS
项目                                                             指示剂级     
                                                                     (IND) 
染料含量Dye content                                ≥90.0% 
灼烧残渣Ignition residue(Sulfate)            ≥1% 
醇溶性实验Solubility in  EtOH(50vol/%)  溶液透明
pH变色范围 pH range                              1.2(红) - 2.8(黄) 
                                                                     8.0(黄)  - 9.8(紫)
项目                                                              高纯级     
                                                                       (High pure grade)
纯度Purity                                                     ≥95.0% (HPLC) 
吸光度Absorbance                                      ≥0.370(10 mg/L, pH 7.0, 433.0 - 437.0 nm) 
PH变色域Transition interval(pH)               1.2(红) - 2.8(黄)
                                                                       8.0(黄)  - 9.6(略带点紫色的蓝色)
醇溶性实验Solubility in EtOH(50vol/%)   溶液透明
灼烧残渣Ignition residue(Sulfate)             ≤0.5 %  

用作酸碱指示剂。
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