Amino‐Montmorillonite Crystalline Clay as Electrode Modifier for Electrochemical Detection of Ciprofloxacin in Presence of Cetyltrimethylammonium Bromide

Abstract

This research focused on harnessing amino‐functionalized montmorillonite (Mt) clay, achieved through the grafting of [3(2‐aminoethyl)amino]propyltrimethoxysilane (AEP‐TMS), as carbon paste electrode (CPE) modifier for the electroanalysis of ciprofloxacin (CF). The characterization of both Mt and the amino‐functionalized (Mt‐NH2) materials was carried out using various techniques including Fourier‐transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X‐ray diffraction (XRD). Afterwards, various CPEs modified using Mt and Mt‐NH2 were prepared and characterized employing SEM‐energy dispersive X‐ray (EDX), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). By EIS, Mt‐NH2‐CPE exhibited significantly faster electron transfer with lower charge‐transfer resistance (438.5 Ω) compared to Mt‐CPE (3572.1 Ω) and to the bare CPE (2066.1 Ω). Additionally, CV experiments performed by using redox probes demonstrated the excellent accumulation capability of [Fe(CN)6]3− ions on Mt‐NH2‐CPE surface. The Mt‐NH2‐CPE was subsequently applied using square wave voltammetry to determine CF in the presence of cetyltrimethylammonium bromide (CTAB), yielding an impressive linear range from 30 to 240 μM (R=0.999) and a low detection limit of 0.07 μM (23.2 μg L−1). The method exhibited stable and reproducible responses (RSD=3.25 %; n= 6) under optimized conditions. Following interference studies, the optimized method was effectively applied to quantify CF concentrations in pharmaceutical and water samples.