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.
Highlights
Doxepin (Figure 1) has been widely used as an effective tricyclic antidepressant in the treatment of psychiatric disorders over the past decades [1,2]
Reported literature methods mainly focus on chromatographic techniques, such as reversed-phase liquid chromatography with ultraviolet detection [3], thin-layer chromatography-densitometry method [4], HPLC or LC-MS [5,6,7,8], and capillary zone electrophoresis [9], etc
The electropolymerization of 1.0 10−4 M 4-ABA in 0.10 M PBS at MWNTs/GCE is given in the repetitive cyclic voltammograms of Figure 2
Summary
Doxepin (Figure 1) has been widely used as an effective tricyclic antidepressant in the treatment of psychiatric disorders over the past decades [1,2]. Carbon nanotube (CNT)-modified electrodes have been successfully applied to study antidepressants [17], owing to the excellent conductivity and catalytic activity of CNTs. On the other hand, conductive polymers (CPs), with unique high stability and selectivity characteristics, good conductivity and reproducibility, more active sites and good homogeneity, have been used to detect antidepressants [18,19,20]. Conductive polymers (CPs), with unique high stability and selectivity characteristics, good conductivity and reproducibility, more active sites and good homogeneity, have been used to detect antidepressants [18,19,20] These electrodes functionalized solely with CNTs or CPs presented excellent accumulation and electrocatalytic activities toward the targets. Analytical conditions, such as amount of MWNTs, electropolymerization conditions, pH and buffer solution, accumulation time and potential, were optimized
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