A Novel Colorimetric Reagent for Potassium Based on Crown Ether Complex Formation

Abstract

Abstract The extraction study of alkali metal ions was made with a new type of crown ether, 4′-picrylaminobenzo-15-crown-5 (HL). Upon dissociation in alkaline medium orange-colored HL gives blood-red anion, L−, and extracts selectively K+ (and to a lesser extent Rb+) ion into chloroform as a colored complex of composition ML·HL. A colorimetric determination of 10 - 400 ppm K+ in the presence of < 2000 ppm Na+ was possible using this new crown ether reagent.