Unveiling the effect of crystallinity and particle size of biogenic Ag/ZnO nanocomposites on the electrochemical sensing performance of carbaryl detection in agricultural products

Abstract

In this study, bio-Ag/ZnO NCs were synthesized via a microwave-assisted biogenic electrochemical method using mangosteen (Garcinia mangostana) peel extract as a biogenic reducing agent for the reduction of Zn²⁺ and Ag⁺ ions to form hybrid nanoparticles. The as-synthesized NC samples at three different microwave irradiation temperatures (Z₇₀, Z₈₀, Z₉₀) exhibited a remarkable difference in size and crystallinity that directly impacted their electrocatalytic behaviors as well as electrochemical sensing performance. The obtained results indicate that the Z₉₀ sample showed the highest electrochemical performance among the investigated samples, which is attributed to the improved particle size distribution and crystal microstructure that enhanced charge transfer and the electroactive surface area. Under the optimal conditions for carbaryl pesticide detection, the proposed nanosensor exhibited a high electrochemical sensitivity of up to 0.303 μA μM⁻¹ cm⁻² with a detection limit of LOD ∼0.27 μM for carbaryl pesticide detection in a linear range of 0.25–100 μM. Overall, the present work suggests that bio-Ag/ZnO NCs are a potential candidate for the development of a high-performance electrochemical-based non-enzymatic nanosensor with rapid monitoring, cost-effectiveness, and eco-friendly to detect carbaryl pesticide residues in agricultural products.