Ultrasensitive detection of carbendazim pesticide in tea leaves using a green Ag/CuO(CuO) nanocomposite-based SERS sensor: role of metal/semiconductor transition in sensing performance

• Published in: RSC advances Vol. 15; no. 22; pp. 17635 - 17647
• Main Authors: Thi Linh, Dong, Mai, Quan-Doan, Thi Hanh Trang, Dang, Anh, Nguyen Tuan, Vu, Xuan Hoa, Le, Anh-Tuan
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 21.05.2025; The Royal Society of Chemistry
• Subjects: Chemical fingerprinting; Chemistry; Copper oxides; Environmental monitoring; Metal/semiconductor transitions; Nanocomposites; Pesticides; Raman spectroscopy; Reliability; Reproducibility; Sensitivity; Silver
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/d5ra00846h

Surface-enhanced Raman spectroscopy (SERS) is increasingly recognized as a powerful tool for analytical applications, especially in food safety, due to its ability to detect molecular fingerprints even at the single-molecule level. Developing SERS substrates that offer not only high sensitivity but also reliability and practicability is critical for transitioning SERS from a laboratory-based technique to practical field applications. In this study, we present an outstandingly sensitive, reliable, and practical Ag/CuO nanocomposite SERS substrate, fabricated through a simple green electrochemical method. The Ag/CuO substrate demonstrates remarkable sensitivity, detecting carbendazim (CBZ), a hazardous pesticide widely used in tea leaves, at an ultra-low limit of 8.85 × 10 −11 M, outperforming bare Ag substrate, which only reaches 10 −6 M. The high reliability of the Ag/CuO substrate is confirmed by excellent repeatability and reproducibility, with a relative standard deviation (RSD) of less than 10%. Practicability was validated through the direct detection of CBZ in fresh tea leaves, yielding sharp recovery values of 85% to 106%. Additionally, the SERS enhancement mechanism was explored by comparing the performance of Ag, Ag/Cu 2 O, and Ag/CuO substrates, revealing the critical role of metal (Ag) and semiconductor (Cu 2 O, CuO) transitions in overall sensing performance. These findings underscore the potential of Ag/CuO nanocomposites for ultrasensitive pesticide detection in real-world agricultural environments and highlight the importance of metal/semiconductor transitions in designing more efficient SERS substrates. This paves the way for the development of versatile, field-ready SERS platforms applicable to a wide range of analytical and environmental monitoring needs. In this study, we developed an ultrasensitive and practical Ag/CuO-based SERS substrate for reliable detection of carbendazim in tea leaves, highlighting the synergistic enhancement from metal/semiconductor transitions.