Construction of a Fe3+ Carbon Paste Electrode Based on Multi-walled Carbon Nanotubes (MWCNTs)/Nanosilica

摘要

The results of our previous studies showed a selective interaction between Di-tert- 3+ butylazodicarboxylate (TBADC) and Fe ions respect to other metal ions. A new carbon paste ionselective electrode for determination of iron amount was prepared. Using multi-walled carbonnanotube (MWCNT) and nanosilica in the composition of carbon paste electrodes (CPEs) causeimprovement in their characterizations. The best performance for nano-composite sensor was obtainedwith electrode composition of 4% TBADC, 0.3% nanosilica, 30% paraffin oil (binder), 62.7% graphite3+ powder, and 3% MWCNT. The new Fe -CPE showed a Nernstian slope of 19.90.4 mV per decade-10 -1 -9 -2 -1 with a detection limit of 8.010 mol L in the range of 1.010 -1.010 mol L . The sensor couldbe used in a pH window of 1.6.3 and the response time of the sensor was at least 5 s, in addition to3+ its very good Fe selectivity over many mono-,di- and trivalent transition and heavy metal ions. Theproposed sensor was successfully applied as an indicator electrode for the potentiometric titration of 25-2 -1 3+ -4 -1 mL of a 1010 mol L Fe ions with a 1010 mol L EDTA and the monitoring of the Fe(III)concentration ions in some cationic mixtures.