A Novel Electrochemical Sensor for Probing Doxepin Created on a Glassy Carbon Electrode Modified with Poly(4-Amino- benzoic Acid)/Multi-Walled Carbon Nanotubes Composite Film

Abstract

A novel electrochemical sensor for sensitive detection of doxepin was prepared, which was based on a glassy carbon electrode modified with poly(4-aminobenzoic acid)/multi-walled carbon nanotubes composite film [poly(4-ABA)/MWNTs/GCE]. The sensor was characterized by scanning electron microscopy and electrochemical methods. It was observed that poly(4-ABA)/MWNTs/GCE showed excellent preconcentration function and electrocatalytic activities towards doxepin. Under the selected conditions, the anodic peak current was linear to the logarithm of doxepin concentration in the range from 1.0 × 10−9 to 1.0 × 10−6 M, and the detection limit obtained was 1.0 × 10−10 M. The poly(4-ABA)/MWNTs/GCE was successfully applied in the measurement of doxepin in commercial pharmaceutical formulations, and the analytical accuracy was confirmed by comparison with a conventional ultraviolet spectrophotometry assay.

Electrochemical studies of ropinirole, an anti-Parkinson’s disease drug

“…In supporting electrolytes pH values above 5.0, ROP gave two separate oxidation steps. Taking into account the break point of Ep 2 vs. pH plot for Ox 2 and anodic voltammetric behaviour of some drugs which have tertiary amine group as only electroactive site on the molecule like doxepin, 25 the second oxidation step (Ox 2 ) appeared in neutral and alkaline conditions could be located on the aliphatic nitrogen. After deprotonation, ROP lost an electron to form a cation radical which in subsequent step formed a quaternary Schiff base by losing a proton and an electron.…”

Amperometric Detection of Dopamine based on a Graphene Oxide/PEDOT:PSS Composite Electrode

“…CV was performed from −1.4 to + 2.4V for ten cycles with a scan rate of 100 mV s −1 . Before being used, the modified electrode was again electropolymerized with CV from +0.3 to +1.2 V in a 0.1 M phosphate buffer solution of pH 7 until it was a stable cyclic voltammogram (Xu et al, 2010).…”

Bioelectroanalysis of pharmaceutical compounds

“…Poly(4-amino-benzoic acid) was used instead of Nafion to measure doxepin [256], polycysteic acid for sinomenine [257] and chitosan matrices either to measure acetaminophen and mefenamic acid simultaneously [258] or dipyrone [259]; in this latter case, the CNTs are covalently bound to the matrix [259]. Single-walled carbon nanotube (SWCNT)-and MWCNT-modified carbon ceramic electrodes were compared for nanomolar detection of acetaminophen [260], it being found that the current enhancement and electrocatalytic effects were better using SWCNT.…”