Fabrication of a novel transparent SERS substrate comprised of Ag-nanoparticle arrays and its application in rapid detection of ractopamine on meat

Authors: YAN, BIN - Chinese Academy Of Sciences; SUN, KEXI - University Of Science And Technology Of China; Chao, Kuanglin - Kevin Chao; ALHARBI, NJUD - King Abdulaziz University; LI, JIAXING6 - Chinese Academy Of Sciences; HUANG, QING - Chinese Academy Of Sciences

Submitted to: Journal of Food Analytical Methods
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/28/2018
Publication Date: 6/10/2018
Citation: Yan, B., Sun, K., Chao, K., Alharbi, N., Li, J., Huang, Q. 2018. Fabrication of a novel transparent SERS substrate comprised of Ag-nanoparticle arrays and its application in rapid detection of ractopamine on meat. Journal of Food Analytical Methods. https://doi.org/10.1007s12161-018-1216-z.
DOI: https://doi.org/10.1007s12161-018-1216-z

Interpretive Summary: Ractopamine is a feed additive which promotes leaner meat in swine and cattle. The use of standard analytical chemistry methods to detect trace amounts of ractopamine is time-consuming, laborious, and require skilled manpower. In this study, we have developed a rapid sensing method to detect ractopamine in real-time. A portable 785 nm Raman spectroscopic system was used to detect ractopamine in solution. The method could detect ractopamine in solution with a detection limit as low as 10-8 M, which is lower than the industry regulatory standard concentration of 10 µg/L. This rapid screening technology provides a direct and practical method for detecting ractopamine in meats without the requirement of isolating, extracting or concentrating the analyte before obtaining a measurement. Screening for ractopamine can be required for domestic livestock consumption or its export. The results of this study will serve as a foundation for further research to adapt the method for screening other possible veterinary drugs in animal products.

Technical Abstract: Surface-enhanced Raman spectroscopy (SERS) is an emerging analytical tool that boasts the feature of high detection sensitivity and molecular fingerprint specificity attracting increased attention and showing promise in applications including detecting residues of veterinary drugs. In practice, special pretreatments of samples are generally necessary which can restrict the extension of its applications, particularly in opaque food samples. To solve this problem, we proposed a new approach of detecting trace amounts of ractopamine using a transparent SERS substrate. The SERS substrate was fabricated based on anodic aluminum oxide (AAO) template, from which a conical-pore AAO template with regularly ordered Al2O3 nanotips on the surface was formed using a multi-step process of anodization and etching, followed by removal of remaining aluminum and sputtering silver nanoparticles (Ag-NPs) on the nanotips on the surface. The as-fabricated transparent SERS substrate could detect ractopamine in solution with a detection limit as low as 10-8 M, which was lower than the provision of the international standard concentration of 10 µg/L, and was also confirmed to be sensitive enough for detecting trace ractopamine in meat. Therefore, this work not only demonstrates an easy approach to fabrication of a novel transparent SERS substrate, but also provides a convenient and effective solution to the problem of measuring trace chemical residues on the surface of opaque food samples.