A Novel Glassy Carbon Electrode Modified with Multi-Walled Carbon Nanotubes for Potentiometric Xipamide Determination

Abstract

Solid contact electrodes are widely used in analytical fields due to their outstanding performance over classical ones. However, they showed formation of a water layer affecting stability of those electrodes’ type. Herein, we develop a solid contact ion selective electrode to overcome this common drawback through application of multi-walled carbon nanotubes as a hydrophobic layer between the ion sensing membrane and a glassy carbon electrode. This fine modification improved stability of the electrode via preventing the formation of this water layer. The obtained potential was steady over 30 days with a drift of ∼0.8 mV h−1. The MWCNTs-modified electrode was used for determination of xipamide with a Nernstian slope of −56.01 over a linearity range of 1.0 × 10−5–1.0 × 10−2 mol l−1 and detection limit of 6.0 × 10−6 mol l−1. The proposed sensor was effectively applied for determination of the cited drug in its marketed pharmaceutical dosage form and spiked human plasma.