Electrochemical sensing of dobutamine, paracetamol, amlodipine, and daclatasvir in serum based on thiourea SAMs over nano-gold particles-CNTs composite

We report in this work a one-step approach for the formation of self-assembled monolayers (SAMs) from thiourea (TU) over gold nanoparticles dispersed in carbon nanotubes (CNTs-Aunano). The fabrication of the...

Electroanalytical Analysis of Guaifenesin on Poly(Acridine Orange) Modified Glassy Carbon Electrode and its Determination in Pharmaceuticals and Serum Samples

BACKGROUND

Electroanalytical methods are very functional to detect drugs in pharmaceuticals (tablets, syrups, suppositories, creams, and ointments) and biological samples.

OBJECTIVE

This study is aimed to make selective, sensitive, simple, fast, and low cost electrochemical analysis of expectorant drug guaifenesin in pharmaceuticals and serum samples.

METHODS

Differential pulse adsorptive stripping voltammetric method for determination of guaifenesin on a poly(acridine orange) modified glassy carbon electrode has been developed. Glassy carbon electrode was modified with electropolymerization of the acridine orange monomer for the sensitive determination of guaifenesin. Guaifenesin provided highly reproducible and welldefined irreversible oxidation peaks at +1.125 V and +1.128 V (vs. Ag/AgCl) in the selected supporting electrolyte and human serum samples, respectively.

RESULTS

Under optimized conditions, linear response of peak current on the concentration of guaifenesin has been obtained in the ranges of 2.00×10-7 to 1.00×10-4 M in Britton Robinson buffer solution at pH 7.0 and 4.00×10-7 to 1.00×10-4 M in serum samples. The precision of the method was detected by intraday and inter-day repeatability studies in the supporting electrolyte and serum samples media.

CONCLUSION

The analytical applicability of the proposed method exhibited satisfying determination results for guaifenesin from pharmaceutical dosage forms (syrup) and human serum samples without any pre-separation procedures.

A novel electrochemical sensor for the analysis of β-agonists: the poly(acid chrome blue K)/graphene oxide-nafion/glassy carbon electrode

A novel modified electrode was constructed by the electro-polymerization of 4,5-dihydroxy-3-[(2-hydroxy-5-sulfophenyl)azo]-2,7-naphthalenedisulfonic acid trisodium salt (acid chrome blue K (ACBK)) at a graphene oxide (GO)-nafion modified glassy carbon electrode (GCE). The characterization of an electrochemically synthesized poly-ACBK/GO-nafion film was investigated by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), atomic force microscopy (AFM) and scanning electron microscopy (SEM) techniques, and the results were interpreted and compared at each stage of the electrode construction. Electrochemical oxidation of eight β-agonists - clenbuterol, salbutamol, terbutaline, ractopamine, dopamine, dobutamine, adrenaline, and isoprenaline, was investigated by CV at the different electrodes. At the poly-ACBK/GO-nafion/GCE, the linear sweep voltammetry peak currents of the eight β-agonists increased linearly with their concentrations in the range of 1.0-36.0 ng mL(-1), respectively, and their corresponding limits of detection (LODs) were within the 0.58-1.46 ng mL(-1) range. This electrode showed satisfactory reproducibility and stability, and was used successfully for the quantitative analysis of clenbuterol in pork samples.