A two-channel chemosensor for the optical detection of carboxylic acids, including cholic acid

Abstract

A neutral receptor, in which a urea fragment has been equipped with two naphthaleneimide subunits, on interaction with acetate, in a DMSO solution, undergoes deprotonation of one of the N–H fragments; an event which is signalled by a yellow-to-red colour change and by the quenching of the blue fluorescence of the naphthalneimide subunit, with no competition by a number of anions (phosphate, nitrate, sulfate, chloride or bromide). This procedure can be employed for the visual and spectroscopic detection of cholic acid, even in presence of the other competing bile acids, such as glycocholic and taurocholic.