A Universal and Robust Protocol for Accurate Urea Quantification in Electrochemical C─N Coupling Systems

Electrochemical conversion of CO 2 and nitrate into urea offers a sustainable route for nitrogen fixation, yet the reliability of catalytic performance evaluation is frequently compromised by inaccurate product quantification. Current detection methodologies are susceptible to severe interferences from electrolyte pH fluctuations, byproduct accumulation (e.g., NO 2 − , NH 3 ), and complex electrolyte factors. In this study, we systematically decouple the interference mechanisms affecting these mainstream detection methods, revealing that extreme pH conditions lead to significant quantitative deviations in urease-based assays due to enzymatic denaturation. To overcome these limitations, we establish a comprehensive calibration strategy and a multi-method synergistic detection protocol. This approach integrates targeted pH optimization with a logic-guided selection of analytical techniques based on specific concentration ranges and impurity profiles. Validated using a BiOCl-catalyzed urea synthesis system, this integrated protocol demonstrates exceptional accuracy, stability, and cross-method consistency. By offering a standardized, high-throughput-compatible workflow for eliminating false positives and measurement errors, this work provides critical methodological support for the objective assessment of electrocatalytic urea synthesis. Graphical This study systematically evaluates matrix interferences in electrochemical C─N coupling for urea quantification. We define specific boundaries where ammonia and nitrite byproducts cause measurement deviations and elucidate the impacts of pH on detection methods. An integrated multi-method protocol is established and validated using a BiOCl catalyst, delivering a standardized workflow for the objective assessment of performance.