Construction and performance characteristics of new ion selective electrodes based on carbon nanotubes for determination of meclofenoxate hydrochloride

This work offers construction and comparative evaluation the performance characteristics of conventional polymer (I), carbon paste (II) and carbon nanotubes chemically modified carbon paste ion selective electrodes (III) for meclofenoxate hydrochloride are described. These electrodes depend mainly on the incorporation of the ion pair of meclofenoxate hydrochloride with phosphomolybdic acid (PMA) or phosphotungestic acid (PTA). They showed near Nernestian responses over usable concentration range 1.0 × 10−5 to 1.0 × 10−2 M with slopes in the range 55.15–59.74 mV (concentration decade)−1. These developed electrodes were fully characterized in terms of their composition, response time, working concentration range, life span, usable pH and temperature range. The electrodes showed a very good selectivity for Meclo with respect to a large number of inorganic cations, sugars and in the presence of the degradation product of the drug (p-chloro phenoxy acetic acid). The standard additions method was applied to the determination of MecloCl in pure solution, pharmaceutical preparations and biological samples. Dissolution testing was also applied using the proposed sensors.

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► Three different meclofenoxate electrodes were prepared.
► They showed responses over range 1.0 × 10−5 to 1.0 × 10−2 M with slope of 5.15–59.74 mV (concentration decade)−1.
► The electrodes showed good selectivity for Meclo over many inorganic cations and compounds.
► Better sensitivity was obtained on using carbon nanotubes as modifiers.
► The electrodes were used successfully for the assay of dosage forms and in biological samples.