Potentiometric Responses of Ion-Selective Electrodes Doped with Diureidocalix[4]arene towards Un-dissociated Benzoic Acid

Diureidocalix[4]arene have been applied as new ionophore in liquid membraneelectrode (ISE) sensitive towards un-dissociated benzoic acid. The electrode demonstratedresponse towards benzoic acid with the detection limit 2.0 x 10-4 M which is sufficient forthe determination of benzoic acid added to beverages as preservative in milimolarconcentration. The selectivity coefficients measured by the matched potential method(MPM) showed its good selectivity against common anions present in drink samples. Allmeasurements were made in presence of 1.0 x 10-2 M NaHSO4 pH 3.0 in order to reducethe influence of OH-. The applicability of diureidocalix[4]arene incorporated ISE has beenchecked by recovery test of benzoic acid in the presence of artificial drink matrix and bystandard addition method.