Two fabricated carbon paste electrodes for novel potentiometric determination of probenecid in dosage form and human plasma

Solid contact ion selective electrodes are extensively utilized owing to their marvelous performance over traditional liquid contact ones. The main drawback of those solid contact electrodes is aqueous layer formation which affects their constancy. Herein and to overcome this common drawback, a carbon paste electrode containing poly(3,4-ethylenedioxythiophene) was constructed and used for determination of probenecid at variant pH values. This modification decreased the potential drift down to 0.8 mV/h and improved its stability over 30 days. A Nernstian slope of - 57.8 mV/decade associated with a linear range of 1.0 x 10(-6)-1.0 x 10(-2) mol/L was obtained. The modified carbon paste electrode successfully detected up to 8.0 x 10(-7) mol/L probenecid. Results of this modified carbon paste electrode were also compared to unmodified one.

Automated summary

Solid contact ion selective electrodes are widely used due to their excellent performance compared to traditional liquid contact electrodes. However, their main drawback is the formation of aqueous layer, which affects stability. This study successfully overcomes this drawback by using a modified carbon paste electrode.