Surface-enhanced Raman scattering (SERS) is the basis of an increasing number of onsite sensors for both food authenticity and food contaminant applications. However, its practical application to filament-type herbal materials such as saffron remains challenging, largely because their irregular surfaces hinder efficient sampling and lead to poor hotspot uniformity.
In this paper (purchase required, USD $36) the authors report a design modification that overcomes this hurdle. They designed a template-assisted electrospun fiber membrane with well-ordered microcone arrays (EFM-OMA) as a flexible 3D SERS platform. They report that this architecture provides a highly repeatable nanoscale enhancement environment, enabling dense and uniform AgNPs-based hotspots across the entire substrate. This structure not only enhances electromagnetic coupling but also significantly improves molecular collection efficiency during swabbing of irregular solid samples.
They applied the sensor to adulterated saffron. They report good sensitivity and signal reproducibility, meaning that the full-spectrum fingerprints obtained from the swab can be reliably analyzed using a Random Forest classifier, enabling accurate identification of dye-adulterated saffron. They report easy and pretreatment-free discrimination of pure vs dye-adulterated saffron.
