Rapid and Accurate Identification of Dyes on Ancient Textiles by SERS With a Negligibly Invasive Approach

Nowadays, surface-enhanced Raman spectroscopy (SERS) has become a powerful tool for rapidly detecting and analyzing textile cultural relics due to its ability to provide chemical information with single-molecule sensitivity. However, preserving a high level of detection sensitivity while avoiding sample damage remains a persistent challenge. In this work, we developed a SERS approach with both microextraction and detection functions. The alcohol–water droplet with iodide-modified Au nanoparticles (AuIMNPs) is directly dropped on the textile, where dyes strongly bound on textiles can be extracted by ethanol (EtOH). As a result, the sample can be well preserved from being damaged. In particular, the volatility of EtOH allows the molecules to be captured in the hot spots through the capillary effect during droplet evaporation, resulting in a dramatic increase in Raman signal intensity. This highly sensitive strategy can be used to measure dyes in plant extracts and mock-up textiles. Furthermore, the capability of SERS to provide fingerprint information allows us to distinguish different dyes in overdyeing textiles. Eventually, this approach is successfully applied to identify dyes of authentic ancient Chinese textiles. This rapid, universal, and negligibly invasive approach provides a powerful way to study textile cultural relics.