Stable glycopyrronium bromide solid contact ion selective potentiometric sensors using multi-walled carbon nanotubes, polyaniline nanoparticles and polyaniline microparticles as ion-to-electron transducers: A comparative study

Glycopyrronium bromide solid contact ion selective potentiometric sensors using multi-walled carbon nanotubes (MWCNTs), polyaniline nanoparticles (PANI NPs) and microparticles (PANI MPs) as ion-to-electron transducers were fabricated and compared to transducer free blank sensor. Their inclusion in solid contact (SC) sensors offer shorter response time, lower potential drift and longer life time. From a comparative point of view, inclusion of MWCNTs offer longer lifetime (50 days) to the SC sensor compared to PANI based SC sensors. While, the inclusion of PANI showed shorter response times. Hence, PANI-based sensors showed better stability on short term, while MWCNTs offered long term stability. PANI NPs gave faster response than MPs. This may be attributed to the higher surface/volume ratio in NPs which enlarges the contact area with the polymeric membrane, increasing the transduction at the interface. Moreover, PANI NPs showed lower potential drift and relatively longer life time than MPs. Nano-sized particles result in smooth surfaces with a good surface coverage (protection) of the underlying SC. The proposed sensors were successfully applied to content uniformity testing of GLY in a newly approved pharmaceutical dosage form with high accuracy. (C) 2017 Elsevier B.V. All rights reserved.