Ecofriendly Long Life Nanocomposite Sensors for Determination of Carbachol in Presence of Choline: Application in Ophthalmic Solutions and Biological Fluids.

Eman A Al-Harbi,Amira M El-Kosasy,Mona H Abdelrahman

doi:10.3390/s19102357

Eman A Al-Harbi, Amira M El-Kosasy + Show 1 more

Open Access

https://doi.org/10.3390/s19102357

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Abstract

Several emerging nano scale forms of carbon are showing great promise in electrochemical sensing such as graphene and multi-walled carbon nanotubes (MWCNTs). Herein we present an ecofriendly method to fabricate long life and sensitive ion selective sensors based on graphene and MWCNTs nanocomposites with no need for volatile organic solvents. Both sensors were fabricated, for the analysis of carbachol in ophthalmic solutions, plasma and urine where ion- association complex was formed between cationic carbachol and anionic Sodium tetra phenyl borate (NaTBP) in a ratio 1:1. Both sensors were evaluated according to the IUPAC recommendation data, revealing linear response in the concentration range 10−7 M to 10−2 M with near Nernstian slopes 50.80 ± 5 and 58.14 ± 3 mV/decade and correlation coefficients 0.9992 and 0.9998 for graphene and MWCNTs based sensors, respectively. Both sensors were successfully applied as stability indicating method for the analysis of carbachol in presence of its metabolite choline, in ophthalmic preparations, in plasma and urine showing good recovery percentage values. MWCNTs based sensor showed some advantages over graphene sensor regarding lower limit of detection (LOD), longer life time and higher selectivity towards carbachol. Statistical comparison of the proposed sensors with the official method showed no significant difference for accuracy and precision.

Highlights

Both graphene and carbon nanotubes are considered to be excellent candidates as second-phase fillers in composite materials as they have exceptional electrical conductivity [1]
We demonstrate for the first time eco-friendly, long-life potentiometric nanocomposite sensors for the accurate, precise, and selective determination of carbachol in ophthalmic solutions, in presence of choline, and in biological fluids
The sensing of thepart of theproposed proposed sensors was the carbon paste formed from incorporating ion-association complex sensors wassetup the carbon paste formed incorporating ion-association of

Summary

Introduction

Both graphene and carbon nanotubes are considered to be excellent candidates as second-phase fillers in composite materials as they have exceptional electrical conductivity [1]. Graphene has been the subject of extensive scientific research since its discovery was reported in 2004 in the journal Science, outlining the isolation of a single atomic layer of graphite [2,3,4] It completes the family of different carbon allotropes that are stable at ambient conditions and is considered as the thinnest, most flexible material known. Graphene is a two-dimensional (2D) sheet of carbon atoms bonded by sp bonds It is a fantastic material for use in electrochemical analysis, owing to the combination of its interesting chemical properties and its unique assortment of physicochemical properties [5,6,7,8].

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