OPTODE FOR 2-PHENETHYLAMINE USING CALIXARENE AS HOST MOLECULE

Calixarene ethoxycarbonyl ester is synthesized and used as a host mole cule in optical detection of 2-phenethylamine. A plasticized poly(viny l chloride) membrane containing the calixarene and a fluorescent dye r esponds to 2-phenethylamine reversibly, and the sensitivity of an opto de is increased by substitution of the ethoxycarbonyl ester for a hydr oxy group in calixarene. However, a large interference response to pH is observed when the membrane contains calixarene. A phenolic proton i s dissociated with an increase of pH, and fluorescence from the membra ne is quenched by deprotonated calixarene, which causes the interferen ce response to pH. The guest molecule of 2-phenethylamine is incorpora ted inside the calixarene, and the proton dissociation in calixarene o ccurs upon complexation. It results in the optode response to the gues t molecule. The response to alkyl ammonium ions is also investigated, and the selectivity of the optide is discussed.