A simple smartphone-assisted homogeneous colorimetric platform based on laccase-like Cu-GMP system for phenolic compounds detection

Laccase-like Cu-GMP complex forms directly without tedious synthesis. • The homogeneous system effectively avoids light-scattering interference. • The platform detects 2,4-DCP, BPA and epinephrine with low detection limits. • Smartphone-based colorimetry enables portable, low-cost on-site detection. • Good recoveries are achieved in lake water and human serum samples. The rapid and sensitive screening of phenolic compounds is essential for environmental safety and clinical diagnostics. Although laccase-like Cu-based nanozymes offer cost-effective alternatives to natural enzymes, most existing platforms rely on heterogeneous nanoparticles. These systems not only require tedious pre-treatment, but also suffer from light scattering that compromises colorimetric accuracy. Herein, a homogeneous colorimetric sensing platform based on the laccase-like activity of a copper-guanosine 5′-monophosphate (Cu-GMP) complex was developed. The complex is prepared directly in solution without the need for time-consuming synthesis. Furthermore, this homogeneous system eliminates light-scattering interference due to its intrinsic optical transparency. Benefiting from its catalytic versatility, the platform enabled the quantification of three phenolic targets. 2,4-dichlorophenol (2,4-DCP) and bisphenol A (BPA) were detected via 4-aminoantipyrine (4-AAP)-mediated coupling, while epinephrine was quantified by direct catalytic oxidation, with detection limits of 0.22, 0.59, and 0.21 μM, respectively. Additionally, integrating this system with smartphone technology enabled a portable platform for on-site quantification, demonstrating reliable accuracy in lake water and human serum samples. Overall, this work provides a versatile and low-cost homogeneous strategy for the point-of-need screening of phenolic pollutants and biomarkers. Download: Download high-res image (123KB) Download: Download full-size image