A Robust, Uniform, and Stable Glycerol Liquid Film Substrate for In Situ SERS Quantitative Investigation of Contaminant Distribution on Rough Surfaces

Abstract Rapid, in situ, and real‐time molecule mapping on rough surfaces with high accuracy has long been one of the paramount challenges in many fields. Here, an effortless Ag NPs doped glycerol liquid film SERS substrate (g‐LFS) is developed to investigate the distribution of contaminants on different types of rough surfaces. After substrate optimization, the g‐LFS is characterized in terms of uniformity, reproducibility, and stability with time. The substrate showed an excellent signal stability, even after 96.5 h of usage or 19 days of storage, together with great uniformity (7.4% RSD) and reproducibility (7.1% RSD). As a proof of concept, the distribution of Rhodamine 6G(R6G) dye on rough fabric and the R6G migration in different plant types and tissues have been explored. The g‐LFS substrate demonstrated great accuracy, detecting R6G even in deep fabric grooves, recovering 82.4% of the initial concentration. Moreover, the g‐LFS SERS substrate detected significantly different concentrations in root, stem and leave tissues of bean sprouts, as well as between xylem and phloem in vascular plant branches. Overall, the g‐LFS substrate is proven to be well‐suited for in situ detection on rough surfaces with great versatility and robustness, aggregating new opportunities for contaminant investigation on food and plants using SERS.