Yunzhe Han

Portable multi-parameter water quality analyzers are of significant importance in field environments such as exploration and scientific expeditions. However, existing multi-parameter sensor systems suffer from issues such as large size, high cost, and sensor drift, which limit their widespread application. While the emergence of micro-electromechanical systems (MEMS) sensors has brought promise for instrument miniaturization, measurement processes still exhibit heavy reliance on scientific instrumentation. Inspired by thermos design, this paper proposes a MEMS-based portable multi-parameter water quality analyzer featuring compact dimensions (3) and lightweight construction (<300 g), capable of simultaneous detection of five water quality parameters: pH, temperature, conductivity, chemical oxygen demand (COD), and turbidity. The system design includes modular components, MEMS sensor modules, electronic circuits, and system software. By employing time-division multiplexing and predefined sensor compensation algorithms, issues such as electronic crosstalk and drift in multi-parameter detection are resolved, achieving a balance between detection speed and accuracy. Experimental results indicate that the instrument exhibits a linearity (R²) exceeding 0.99 for all water quality parameters tested. The compensation algorithms reduce non-target parameter drift by over 90 %, and the low-power characteristics enable continuous operation for more than 20 hours. In tests involving three different real-world water samples, our instrument system demonstrates performance comparable to that of professional large-scale instruments, with all measurement errors remaining within 2% of the true values. This research provides crucial references for practical implementation and commercialization of portable water quality analyzers, while offering novel solutions for water quality monitoring in complex environments.