Stencil-printed multiplex system for electrochemical determination of carbendazim, ascorbic acid and glucose in juice samples†

This study introduces a novel stencil-printed multiplex platform designed for the simultaneous determination of carbendazim (CBZ), ascorbic acid (AA), and glucose (GLU) in juice samples. Using custom carbon inks and direct printing techniques, the system integrates three distinct sensors on a single device, each optimized for its respective target analyte. The unmodified electrode demonstrated high sensitivity for AA detection using cyclic voltammetry (CV), achieving a limit of detection (LOD) of 0.712 μmol L⁻¹ and a limit of quantification (LOQ) of 2.37 μmol L⁻¹. The GLU biosensor, under chronoamperometry conditions, exhibited a linear range of 0.10–2.50 mmol L⁻¹ with LOD and LOQ of 8.50 and 28.30 μmol L⁻¹, respectively. A modified ink with Zn/Al layered double hydroxide delaminated (dLDH) was applied for CBZ determination by anodic stripping under square wave voltammetry (SWV) conditions, providing a linear range of 1.0–10.0 μmol L⁻¹, with LOD and LOQ of 0.067 and 0.022 μmol L⁻¹. Validation tests in mineral water, coconut water, and commercial juice samples (250-fold dilution) confirmed the platform's reliability using a minimal cell volume of 100 μL. This cost-effective stencil-printed multiplex device delivers excellent results, offering an efficient, reliable, and scalable solution for multi-analyte detection in complex matrices.