Chromium(III) Potentiometric Sensor Based on Para-Tertiary- Butyl Calix(4)arene

A new chromium(III) PVC membrane sensor incorporating p-tertiary-butyl calix[4]arene as ionophore, potassium tetrakis as additive and dibutyl phthalate (DBP) as plasticizer was constructed. The electrode exhibited an excellent potentiometric response over a wide concentration range of 1.0 � 10 � 7 –1.0 � 10 � 1 M with a Nernstian slope of 20 � 0.5 mV per decade. The detection limit was 5.0 � 10 � 8 M. The electrode showed a better performance over a pH range of 3.0–8.0, and had a short response time of about < 15 s.The electrode was successfully applied to potentiometric titration of Cr (III) with EDTA and for direct determination of chromium(III) in waste water.