All-Solid-State PVC-Membrane Cu(II)-Selective Potentiometric Microsensor Based on a Novel Calix[4]arene Derivative

Abstract

In this study, 25,27-dihydroxy-26,28-bis(ethoxycarbonylbutyoxy)-5,11,17,23-p-tert-butylcalix[4]arene was used as an ionophore for the preparation of a novel all-solid-state type microsensor to make a selective potentiometric response towards Cu(II) ions. The optimum membrane composition of the microsensor was determined as 2% (w/w) ionophore, 67% (w/w) bis (2-ethylhexyl) sebacate (DOS), 30% (w/w) polyvinylchloride (PVC), and 1%(w/w) potassium tetrakis 4-chlorophenyl borate (KTpClPB). The Cu(II)-selective microsensor exhibited a highly selective Nernstian response of 31.3±2.1 mV slope (R2: 0.997) with a short response time (15 s) over the concentration range of 10−5 to 10−1 mol L−1 of Cu(II) ions for 8 weeks with no significant difference in potentials. The microsensor was effectively performed in the pH range of 5.0–8.0, with low detection limit as 7.63×10−7 mol L−1, and a temperature range of 15−40 °C. The prepared microsensor was successfully used both as an indicator electrode in the potentiometric titration of Cu(II) ions with EDTA and also in the determination of the Cu(II) content of environmental water samples. When the potentiometric results were compared with ICP-OES, they were found to be in good agreement with ICP-OES results at a 95% confidence level.