Construction of pyrimidine derivatives-copper enzyme mimics as colorimetric sensing elements for efficient detection of phenolic compounds and hydrogen peroxide.

As concerns about environmental pollution grow, the rapid identification and quantification of pollutants have become increasingly vital. In this work, a series of pyrimidine derivatives-Cu enzyme mimics (Cytosine-Cu, Cytidine-Cu, and CMP-Cu) with laccase- and peroxidase-like activity were prepared through the coordination of Cu2+ with different pyrimidine derivatives (PDs). The PDs-Cu enzyme mimics contain high levels of Cu+ and N - Cu coordination structures, which provide sufficient catalytic sites for the substrates. Compared with natural enzymes and other nanozymes, PDs-Cu demonstrate superior substrate affinity, catalytic efficiency, stability, and resistance to interference. It was found that PDs-Cu enzyme mimics have different catalytic activities towards different phenolic compounds. Therefore, a three-channel colorimetric sensor array (CSA) was successfully developed utilizing PDs-Cu as the sensing elements. The CSA can accurately identify different phenolic compounds and their mixtures in seawater and simulated wastewater. Additionally, a colorimetric method for detecting H2O2 in eye drops was developed, featuring a detection range of 0.1-10.0 μM and a limit of quantification of 0.1 μM. This research not only provides a flexible protocol for regulating the catalytic activity of enzyme mimics, but also provides important inspiration for the development of methods for rapid identification and detection of contaminants in the environmental water.