A Miniaturized Electrochemical SERS Chip with 3D Nanoporous Gold Interface for Qualitative and Quantitative Analysis of Organic Pollutants and their Oxidation Intermediates

Polycyclic aromatic hydrocarbons (PAHs) and organophosphorus pesticides (OPPs) are typical pollutants characterized by a wide variety of types, difficulty in degradation, and significant differences in mutagenic and carcinogenic toxicity. However, due to their distinct physicochemical properties, it remains challenging to simultaneously analyze PAHs and OPPs under real environmental conditions within the same simplified detection systems and accurately assess their oxidation-reduction processes. In this study, electrochemical surface-enhanced Raman scattering (EC-SERS), utilizing a microfluidic chip of self-made 3D nanoporous Au loaded with Ag nanoparticles, is employed to analyze PAHs and OPPs in the environment and investigate their oxidation-reduction processes, which displayed excellent sensitivity and selectivity. The chip successfully analyzed three types of PAHs and four types of OPPs, achieving the lowest detection limit of 0.01 ppb, and strong linearity within a certain range. The recovery in real water samples reached 102.89% with a relative standard deviation (RSD) of 13.36%. Furthermore, this system successfully identified different types of pollutants and their concentrations in mixed samples with high accuracy. Meanwhile, preliminary insights into the electrochemical oxidation and degradation processes of these pollutants are provided, offering a first understanding of their transformation mechanisms.