Miniature dual-channel electrochemical 3D-printed sensing platform for enzyme-free screening of L-lactic acid in foodstuffs accompanying pH recognition

Accurate and rapid identification of expired and spoiled food is crucial for food conservation, reducing resource wastage, and preventing food poisoning. This paper presents a portable electrochemical sensing platform supported by a miniature electrochemical workstation and an intelligent pH recognition system, enabling detection of L-lactic acid (L-LA) in food products without enzyme involvement. The system was based on a Cu₂O@CuO multifaceted extended spatial hexapod structure. The synthesized Cu₂O@CuO was characterized by a well-defined multifaceted structure. Significant enzyme-free catalysis was exhibited, and pH responses dominated by anthocyanins were identified through an intelligent image acquisition system. Additionally, we developed an electrochemical detection device for pH assistance during target testing, addressing the limitations of current electrochemical sensors' complex signal acquisition components using 3D-printed fabrication techniques and smartphones. The proposed multifunctional electrochemical workbench based on Cu₂O@CuO was found to offer a preferable linear detection range of 0.1–1000 μM for L-LA, with a low detection limit of 0.027 μM. The visualization of pH determination was introduced as a novel approach for developing advanced electrochemical workbenches. In conclusion, pH-assisted portable electrochemical detection systems hold great potential for immediate food safety identification, particularly in resource-limited areas, facilitating prompt diagnosis and ensuring food safety.