A near-infrared croconium dye-based colorimetric chemodosimeter for biological thiols and cyanide anion

A near-infrared colorimetric chemodosimeter based on a croconium dye, 1,3-bis(4-N,N-diethylamino-2-hydroxyl-phenyl) croconine, was developed to selectively and sensitively probe cysteine, homocysteine, or cysteine–glycine at pH 5.7 and cyanide anion at pH 9.0 in aqueous ethanol solutions.