Development of a sensitive voltammetric sensor for diltiazem determination in biological samples using MWCNT/PPy-PBA modified glassy carbon electrode

A glassy carbon (GC) electrode was modified for diltiazem determination in various samples using the cyclic voltammetry (CV) method. The modification consists of coating a multi-walled carbon nanotubes (MWCNTs) layer on the GC electrode, which is followed by electro-polymerization of pyrrole in the presence of phenyl-boronic acid (PBA). The experimental design was used to find optimum experimental conditions for electrode fabrication and diltiazem determination. Under optimum conditions, the calibration curve of diltiazem is linear in 0.25-2 mu mol/L and 2-80 mu mol/L ranges with a detection limit of (LOD) 7.1 x 10(-8) mol/L. Further application of the GC/MWCNT/PPy-PBA electrochemical sensor for diltiazem determination shows good reproducibility, high sensitivity, and reasonable selectivity with no major interference. These characteristics make the sensor suitable for the determination of diltiazem in biological and pharmaceutical samples. To rationalize the modi-fication on the electrochemical behavior of the sensor regarding diltiazem, geometrical interaction and inter -action energy of the analyte with the sensor surface were investigated using highly accurate quantum mechanical methods implemented in Gaussian 09 software. The calculations fully confirm experimental evidence.

Automated summary

The modified glassy carbon electrode with multi-walled carbon nanotubes and electro-polymerized pyrrole in the presence of phenyl-boronic acid shows effective determination of diltiazem under optimal experimental conditions. The electrochemical sensor exhibits good reproducibility, high sensitivity, and reasonable selectivity, making it suitable for analyzing diltiazem in biological and pharmaceutical samples. Quantum mechanical calculations confirmed the experimental evidence regarding the modification of the sensor's behavior towards diltiazem.