The discovery of metal–organic frameworks (MOFs) has opened a new era in materials science investigations and applications in traditional fields due to their unique structures and properties. Recently, MOF-based surface-enhanced Raman scattering (SERS) has attracted much attention because MOFs can endow substrates with excellent properties to improve the sensing performance of traditional SERS substrates, such as molecular enrichment ability, selectivity, gas sensing capability, and additional chemical enhancement ability. Meanwhile, SERS can provide ultrasensitive fingerprint spectra for the rapid, non-invasive detection of trace analytes via effective SERS substrates. These advantages of the combination of MOFs and the SERS technique greatly advance the development of SERS and widen its application. To better understand this new application scenario, herein, we briefly introduce the recent progress of MOF substrates in SERS, mainly including the unique advantages of MOFs in the sensing performance improvement in SERS. Then, we present representative MOF-based SERS substrates. Furthermore, the SERS application of effective MOF-based substrates is also reviewed, including in food safety, environmental analysis, bio-medicine, real-time monitoring and other SERS applications. Finally, we present our conclusions and perspectives.

Toxic formaldehyde is sometimes used illegally as a food preservative, however, on-site rapid analysis of trace formaldehyde in aquatic products remains a challenge. In this work, a simple on-site rapid quantification method for trace volatile formaldehyde in aquatic products was developed by a derivative reaction-based surface enhanced Raman spectroscopy (SERS) technique coupled with a homemade portable purge-sampling device. Trace formaldehyde separated from complicated aquatic matrices via a purge-sampling procedure was reacted with a derivative reagent to produce a Raman-active analyte for consequent SERS analysis. Au/SiO₂ nanoparticles (NPs) were employed as the enhancement substrate to achieve significant enhancement of Raman signal intensity. Conditions of derivative reaction and SERS detection were optimized in detail, and the selectivity of this analytical method was also evaluated based on related analogs. Under optimal conditions, an extremely low detection limit of 0.17 μg L⁻¹ was achieved. Trace volatile formaldehyde can be found in fresh squid and shrimp samples without obvious matrix interference, and this was quantified to be 0.13–0.21 mg kg⁻¹ using the described method. The recoveries of spiked aquatic product samples were found to be 70.0–89.1% with RSDs of 2.3–7.2% (n = 3). The results suggest that the proposed method is reliable and suitable for on-site rapid analysis of trace formaldehyde in aquatic products.