Knowledge Bank

Development of an aqueous colorimetric anion indicator is imperative to the health and well-being of the peoples of remote areas where arsenate, cyanide and sulfide contaminate much of the drinking water. Very few examples exist that retain their anion selectivity in water, so many molecules must be synthesized and analyzed to determine which functional motifs warrant the development of an exhaustive structure-activity relationship for aqueous colorimetric anion indication. Sudan Black B, a commercially available dye, which possesses a crude colorimetric effect in the presence of bromide, inspired the synthesis of similar molecules. A planar support was developed to allow for the time-efficient, parallel synthesis of an array of azo compounds, which could be analyzed, without cleavage, by UV-Vis-NIR spectroscopy for convenient determination of their structure and colorimetric effect.