Sensitive SERS detection of pesticide residues in beverages based on an extraction integrated plasmonic platform

Abstract

Organic extraction is a commonly used pretreatment method for the detection of pesticide residues in food samples. However, this process increases the complexity for surface-enhanced Raman scattering (SERS) detection since the traditional sol-based SERS substrates are usually aggregated in organic solvents, while the drop-on-solid method always leads to inevitable coffee-ring effect. Therefore, in this study, an extraction integrated plasmonic platform was developed to achieve the sensitive surface-enhanced Raman scattering (SERS) detection of pesticide residues in beverages. This platform was based on a floating SERS substrate (HSM@AuNPs) that was fabricated by evenly decorating gold nanoparticles (AuNPs) on hollow silica microspheres (HSMs). The HSM@AuNPs can self-located at water/oil interface and can be easily transferred onto a filter paper, thus providing accessible and flexible hot spots for the SERS detection of analytes that were enriched in a bit of extraction phase. We verified that this platform displayed much lower limit of detection (LOD) in the detection of thiabendazole in tea drink (102 ppb) and thiram in apple juice (10 ppb), by using ethyl acetate as extraction solvent. This platform not only provides a sensitive and convenient methodology for the SERS detection of pesticide residues, but also provides new ideas for the application of SERS technology in multi-phase systems.