LAUSR

The calix[4]arene and its mono-, di-, tri-, and tetra-acryloyl esters were used as suitable ionophores for Cr(VI) species to develop poly(vinyl chloride) (PVC) membrane electrodes. The influence of membrane contents and pH on the potentiometric response of the electrodes was described. Five novel chromate-selective PVC membrane electrodes displayed close to Nernstian behavior with slopes of 53–62 mV/decade of hydrogen chromate ion concentration in the dynamic range of 1.0 × 10−6 and 1.0 × 10−2 M at pH 1.0. Other response characteristics of these electrodes such as response time (~10 s), lifetime (>12 months), and detection limit (6.2 × 10−7 M) were identified, and the selectivity coefficients towards various anions were determined by using fixed interference method. Moreover, the proposed electrodes were successfully used for speciation of Cr(VI) and Cr(III) and for the potentiometric titration of Cr(VI) species with standard Fe(II) solution as an indicator electrode.