Self-assembled Au/Ag@MIL(Fe) hybrids for ultra-sensitive SERS detection of furfuryl mercaptan

Developing a high-sensitive platform for furfuryl mercaptan (FFT) detection is significant but remains challenging. Herein, Au/Ag core-shell nanorods@metal-organic frameworks (Au/Ag@MIL(Fe)) hybrids were constructed through electrostatic interaction, which combined the abundant "hot spots" regions caused by Au/Ag NRs and the great enrichment ability of porous MIL(Fe) and amplified the Raman signal greatly, achieving high sensitivity in FFT solution and volatile gas detection. The enhancement factor (EF) of the Au/Ag@MIL(Fe) substrates reaches 3.96 x 107. The linear detection ranges of FFT solution and gas were 10-3 - 10- 8 M and 102 -105 ppb, respectively. The LODs were as low as 4.94 x 10-9 M for solution detection and 77.6 ppb for gas detection and were comparable to HPLC-MS methods. Meanwhile, the Au/Ag@MIL(Fe) hybrids demonstrated favorable reproducibility, stability, selectivity, and successful application for FFT detection in coffee, with a recovery rate from 92.3 % to 108.0 %. The proposed quantitative strategy has significant potential in real food sample analysis.