A magnetic core–shell Fe3O4@SiO2/MWCNT nanocomposite modified carbon paste electrode for amplified electrochemical sensing of amlodipine and hydrochlorothiazide

Abstract

A novel carbon paste electrode modified with a magnetic core–shell Fe₃O₄@SiO₂/MWCNT nanocomposite and an ionic liquid (n-hexyl-3-methylimidazolium hexafluoro phosphate) was fabricated. The electrochemical study of the modified electrode, as well as its efficiency for the simultaneous voltammetric oxidation of amlodipine and hydrochlorothiazide is described. The electrode was also employed to study the electrochemical oxidation of amlodipine and hydrochlorothiazide, using cyclic voltammetry, chronoamperometry and square wave voltammetry as diagnostic techniques. Square wave voltammetry exhibited linear dynamic ranges from 2.5 × 10⁻⁷ to 5.0 × 10⁻⁴ M and 1.0 × 10⁻⁶ to 6.0 × 10⁻⁴ M for amlodipine and hydrochlorothiazide, respectively. Finally, the modified electrode was used for the determination of amlodipine and hydrochlorothiazide in real samples.