Erichrome Black

Objective Examination of the effect of ultrasound on the degradation of Indicators (Murexide, Erichrome black T, Xylenol orange and Fast sulphone black F)... 

Rare earths EDTA Erichrome black T Hexamethylene tetraamine buffer [114]... 

EDTA Erichrome black T Microdetermination at pH 8-9 in presence of tartaric or citric acid [116]... 

The now familiar alternatives of visual and potentiometric detection are available. A number of organic dyes form coloured chelates with many metal ions. These coloured chelates are often discernible to the eye at concentrations of 10" t° 10 7 moldin 3 and can function as visual indicators. Most metal ion indicators will also undergo parallel reactions with protons bringing about similar colour changes. Hence, a careful consideration of pH is prudent when selecting an indicator. Some typical indicators appear in table S.9. Of these, erichrome black T, which forms red complexes with over twenty metal ions, is amongst the most widely used. Its behaviour will serve as a general example of indicator function. 

Erichrome Black T or Calmagite can be used as indicators. If a small quantity of indicator is added to a water sample containing Ca and Ng ions at pH 10, the solution becomes wine-red. The indicator forms complexes with Ca and Mg ions, which give the solution a wine-red color (reaction (21))... 

Direct complexlmetrlc tltratron of lead with 0.07 N complexon III in.the presence of Erichrome Black T as an. indicator has been proposed (Zl). The equivalence point is reached when the color changes from violet to bluegreen. 

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