A New Hybrid β-Cyclodextrin/PAMAM G.0 as an Electrochemical Sensor for Isoniazid Detection

Β-cyclodextrin was functionalized with the polyamide dendrimer PAMAM G.0, and the resulting material was used to adsorb copper before reacting with potassium hexacyanoferrate (II) to form a mixed valence complex on the -cyclodextrin/PamamG.0 surface (β-Cd-PAMAM-Cu/Fe). This material and its precursors were characterized by scanning electron microscopy, x-ray diffraction and by x-ray photoelectron spectroscopy. The β-Cd-PAMAM-Cu/Fe material was successfully tested in the electrocatalytic oxidation of isoniazid (ISO) using cyclic voltammetry (CV) and square wave voltammetry (SWV). ISO is highly selective and effective against Mycobacterium tuberculosis, and used for the treatment of tuberculosis. It can cause drug resistance, neurotoxicity and even hepatic impairment when ISO is consumed in excess, so its detection is highly desirable. The electrochemical performance of the modified sensor exhibited a limit of detection (LOD) of 3.69 × 10⁻⁷ mol L⁻¹ with a linear range from 1.0 × 10⁻⁶ to 1.0 × 10⁻⁵ mol L⁻¹ of isoniazid, using CV. A second region was detected with a limit of detection of 1.98 × 10⁻⁵ mol L⁻¹ with a linear range from 6.0 × 10⁻⁵ to 9.0 × 10⁻⁴ mol L⁻¹ of isoniazid, using CV. In the same way, two linear regions were obtained using SWV, whose LOD was 6.49 × 10⁻⁹ mol L⁻¹ in the concentration range of 5.0 × 10⁻⁷ to 1.0 × 10⁻⁶ mol L⁻¹ and the second region presented a LOD of 1.96 × 10⁻⁷ mol L⁻¹ in the concentration range of 2.0 × 10⁻⁶ to 1.0 × 10⁻⁵ mol L⁻¹. Recoveries ranging from 97.20 to 100.57% were calculated, demonstrating satisfactory accuracy of the proposed method.