Potentiometric polymeric membrane electrodes for mercury detection using calixarene ionophores

It is here established that potentiometric polymeric membrane electrodes based on electrically neutral ionophores are a useful analytical tool for the detection of heavy metal ions from environmental and industrial waste water. PVC based membrane containing p-tert-butyl-calix[4]arenethioether derivative as active material along with sodiumtetraphenylborate (NaTPB) as solvent mediator and dibutylphthalate as a plasticizer in the ratio 45:9:460:310 (w/w%) (I:NaTPB:DBP:PVC) exhibits good properties with a Nernstian response of 29.50±1.0 mV per decade of activity and a working concentration range of 7.2 × 10⁻⁸–1.0 × 10⁻¹ M. The electrode gave more stable potential readings when used around pH 2.5–6.8 and exhibits fast response time of 14 s. The sensors were found to work satisfactorily in partially non-aqueous media up to 40% (v/v) content of acetone, methanol or ethanol and could be used over a period of 7–9 months. Excellent selectivity for Hg²⁺ ions is indicated by match potential method and fixed interference method. The sensors could be used successfully in the estimation of mercury in different sample.