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

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 (10 2 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.