Juniper-based Cu@activated carbon functionalized with ethylenediamine: a green platform for non-enzymatic detection of dopamine.

We report a green and scalable strategy to engineer a next-generation dopamine (DA) sensor using copper-based nanoparticles (Cu-based NPs) on activated carbon derived from juniper seeds and functionalized with ethylenediamine (Cu@AC-CONH-CH2CH2-NH2). The carbon matrix, enriched with uniformly dispersed Cu-based NPs and surface-anchored amine groups, delivers abundant catalytic sites, accelerated electron transfer, and exceptional sensitivity. Differential pulse voltammetry revealed three broad linear ranges for DA (0.0015-1 µM, R2 ≥ 0.991), an ultralow limit of detection (LOD) of 1.4 nM, a limit of quantification (LOQ) of 4.7 nM, and a high sensitivity of 92.3 µA µM-1. The electrode exhibited remarkable anti-interference performance against uric acid, ascorbic acid, and urea, ensuring reliable DA quantification even in complex biological environments. Real-sample analysis yielded recoveries of 90.08-106.80%, demonstrating its clinical relevance. This environmentally friendly, low-cost, and high-performance Cu@AC-CONH-CH2CH2-NH2 composite provides a powerful platform for non-enzymatic dopamine sensing, offering a sustainable route toward practical diagnostics and environmental monitoring.