Carbon nanotube composite PVC coated stainless steel disc electrode for detection of Ga(III)

Abstract

This study demonstrates the application of the composite of multi-walled carbon nanotube polyvinylchloride (MWCNT-PVC) based on Bismarck Brown R for gallium sensor. MWCNT has a role to enhance the hydrophobicity of the membrane, which leads to a more stable potential signal. In addition by applying polypyrrol on the surface of this sensor a reduction in the drift of potential occurred and equilibrium potential was achieved faster. Compared to previous studies, using a stainless steel disc instead of a wire electrode causes to obtain an easily and more homogeneous coated electrode. The sensor shows a good Nernstian slope of 19.70 ± 0.37 mV decade⁻¹ in a wide linear range concentration of 1.0 × 10⁻⁷ to 1.0 × 10⁻²M of Ga(NO₃)₃. The detection limit of this electrode was 7.7 × 10⁻⁸M of Ga(NO₃)₃. This proposed sensor is applicable in a wide pH range of 2 to 8. It has a short response time of about 8 s and has a good selectivity over twenty four various metal ions. The practical analytical utility of this electrode is demonstrated by measurement of Ga(III) in rock and different water samples.

Keywords:

• sensor
• ion selective electrode
• Ga(III)
• MWCNT
• polypyrrol
• Bismarck Brown R
• coated disk electrode

Acknowledgements

We gratefully acknowledge the support of this work by the Shiraz University Research Council.