Poly(methyl orange)-modified NiO/MoS₂/SPCE for a non-enzymatic detection of cholesterol

A novel modified electrode has been successfully constructed using nanocomposites consisting of nickel oxide (NiO) and molybdenum disulfide (MoS₂) immobilized on the surface of a screen-printed carbon electrode (SPCE) for non-enzymatic cholesterol detection. Poly(methyl orange) was also immobilized on this electrode surface to act as the cholesterol-identifying agent. The electrochemical activity of the modified electrode toward cholesterol through differential pulse voltammetry showed a linear response (r² = 0.9998) in the cholesterol concentration ranges from 1 to 15 mg/dL with a limit of detection of 0.24 mg/dL, a limit of quantification of 0.81 mg/dL and sensitivity of 7.95 × 10⁻⁶ A mg⁻¹ dL⁻¹ cm⁻². Moreover, this sensor was successfully applied for the quantitative analysis of cholesterol in milk and yogurt samples. Validation using gas chromatography showed an excellent similarity value of 95.2–97.1%.