A new fluorogenic benzothiazolyl ionophore based upon calix[4]arene-crown-5 ether for calcium determination in aqueous media

A new benzothiazolyl functionalized ionophore based upon the calix[4]arene-crown-5 ether has been prepared and its fluoroionophoric properties toward Ca2+ ions were investigated. The compound exhibited a pronouncedly selective fluoroionophoric behavior toward Ca2+ ions among the surveyed physiologically important metal ions of Na+, K+, and Mg2+. Detection limit for Ca2+ ions was found to be 9×10−5 M in dioxane–water (80:20, v/v) solution.