Differential surface partitioning for an ultrasensitive solid-state SERS sensor and its application to food colorant analysis. (30th July 2022)

• Record Type: Journal Article
• Authors: Chien, Yu-San; Chang, Chia-Wen; Huang, Chia-Chi
• Is Part Of: Food chemistry. Volume 383(2022)
• Publication Date: 2022-07-30
• Subjects: SERS -- Hydrophobic -- Oleophobic -- 4-aminophenyl disulfide -- Food colorants; Food -- Analysis -- Periodicals; Food -- Composition -- Periodicals; 664
• DOI: 10.1016/j.foodchem.2022.132415
• Languages: English
• ISSNs: 0308-8146

Abstract

Graphical abstract: Highlights: A AgNPs@alumina bead sensor is developed for the application to POC SERS detection. The bead surface is partitioned chemically to control AgNPs aggregation. Aggregation-induced hot spots allow the detection of APDS at 10 −15 M. The sensor beads are successfully used to analyze food colorants in candies. The sensor is easy to make, ultrasensitive, and satisfactory in real sample tests. Abstract: Solid-state SERS sensors are desirable point-of-care tools due to their portability. However, the level of SERS sensitivity achieved in liquid phase is rarely duplicated in the solid phase. We report herein the fabrication of a SERS sensor using alumina beads as the solid support and demonstrate its high SERS sensitivity with the model analyte 4-aminophenyl disulfide (4-APDS). The key to sensitivity is a hydrophilic-hydrophobic surface gradient constructed by sequentially coating with the surfactant cetyltrimethylammonium bromide and fluorous 1H, 1H, 2H, 2H-perfluorooctyltriethoxysilane. The surface gradient, together with chloride etching, allows the detection of 4-APDS at the low concentration of 10 −15 M. The practicality of the sensor beads is evidenced by successfully tracking the SERS fingerprints of five food colorant standards in the SERS spectra of a popular candy product. These SERS sensor beads are easy to prepare, convenient to use, and highly responsive as a SERS platform for the analysis of colorants.