Electrochemical stripping voltammetrical sensor based on polypyrrole exfoliated polyetheramine-montmorillonite nanocomposite for nanomolar detection of nifuroxazide

Abstract

A series of polypyrrole/polyetheramine-montmorillonite nanocomposites have been fabricated by the intercalation of different types of polyoxyalkylene amine hydrochloride (Jeffamines: D₄₀₀, D₂₀₀₀, T₅₀₀₀, and T₄₀₃) into montmorillonite layers via the cation-exchange process followed by in situ polymerization of pyrrole. The physicochemical characteristics of as-prepared nanocomposites were investigated using Fourier transform infrared (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET), and electrochemical impedance spectroscopy (EIS) instruments. The change of the types of Jeffamine causes a change in the geometrical structure, and surface area of nanocomposites. Noteworthy, the resulting polypyrrole/D₂₀₀₀-montmorillonite ([PDM-50]) nanocomposite exhibited a cauliflower-like shape with a specific surface area (116.2 m² g^-1) with the highest conductivity. Furthermore, the modified stripping voltammetric carbon paste sensor was fabricated based on 1.0% [PDM-50] nanocomposites to detect the drug nifuroxazide (NF). The sensor achieved detection limits (LD) of 0.24, and 0.9 nM of NF in the medication, and human urine fluid, respectively. This sensor showed appropriate repeatability, reproducibility, stability, and selectivity for NF sensing in different fluids accompanied by other interferents.

Fig. 1. X-ray diffraction pattern of Na-MMT, Ppy, organoclay, and Ppy/organoclay nanocomposites at different content of organoclay.

Fig. 2. SEM micrographs of sensor surface with 1.0% of [PT₁M-50] (a), [PTM-50] (b), [PD₁M-50] (c), and [PDM-50] (d).

Fig. 3. SEM micrographs of Ppy (a), Na-MMT (b), [PTM-10] (c), [PTM-50] (d), [PDM-10] (e), and [PDM-50] (f) nanocomposites.

Fig. 4. TEM micrographs of [PDM-50] (a), and [PTM-50] (b).

Fig. 5. SEM micrograph of 0.5 (a), 1.0 (b), 2.0 (c), and 3.0% (d) of [PDM-50] MCPSs.

Fig. 6. SW-AdAS voltammograms of various concentrations of NF in pH 5 upon 1.0% [PDM-50] MCPS in (A) bulk: (a) background, (b) 2.0, (c) 6.0, (d) 8.0, (e) 20.0, (f) 30.0, (g) 60.0, (h) 70.0, (i) 80.0 and (j) 100.0 nM of NF and, (B) spiked human urine: (a) background, (b) 7.0, (c) 9.0, (d) 10.0, (e) 30.0, (f) 50.0, (g) 60.0, and (h) 80.0 nM of NF (E_acc = 0.6 V for 10 s, f = 120 Hz, ΔE_s = 12 mV, and a = 30 mV).