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

摘要

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~(-2)M of Ga(NO_3)_3. The detection limit of this electrode was 7.7 × 10~(-8)M of Ga(NO_3)_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.