Fabrication of a Tb3+ Carbon Paste Ion Selective Electrode by Using Nanosilica and Multi-Walled Carbon Nanotubes (MWCNTs)

摘要

A new Tb carbon paste ion selective electrode based on 1,3-Diaminopropane-N,N,N',N'-tetraaceticacid (DAPTA) for determination of trace amount of terbium was prepared. Using nanosilica and multi- walled carbon nanotube (MWCNT) in the composition of carbon paste electrodes cause improvementin their characterizations. The electrode composition of 20% paraffin oil, 52% graphite powder, 3%DAPTA, 3% WCNTs, and 0.3% nanosilica showed the stable potential response to Tb ions and the-1 -10 -1 Nernstian slope of 20.10.3 mV decade with a detection limit of 9.010 mol L in the wide linear-9 -2 -1 concentration range of 10 -10 mol L . It has a fast response time (~6 s) in the pH range of 3.0.2.3+This sensor presented very good selectivity and sensitivity towards the Tb ions over a wide variety ofcations, including alkali, alkaline earth, transition and heavy metal ions. The practical utility of theproposed chemical sensor has been observed by using it as an indicator electrode in the titration ofTb ions with EDTA.