Microextraction of electric fields and analytes by Janus hydrophobic/hydrophilic microfiber filter: Application in Raman detection of persistent organic pollutants in complex liquid environments

As one of the most pressing environmental issues, the prevention and control of persistent organic pollutants (POPs) continue to garner the attention of various fields. However, there is a lack of effective detection methods for trace amounts of POPs in sewage with a complex composition. To address this, a new Janus microextraction surface-enhanced Raman spectroscopy (SERS) strategy was explored in this study. By designing a Janus glass microfiber filter (GF) membrane structure with a superhydrophobic screening surface and a ZIF-8/Ag/GF detection surface, we demonstrated that POPs molecules in mixed sewage can be sensitively detected and specifically adsorbed and enriched. Thus, a concentration of p-aminothiophenol solution as low as 10-12 M was successfully detected with an enhancement factor as high as 5.16 × 109. Additionally, the collected Raman signal remained unimpeded by impurities such as dye molecules or sediment particles in sewage. Most importantly, the Janus GF substrate enabled the separation and detection of other POPs molecules such as PCB-77, perylene, and pyrene, indicating the immense potential of the Janus SERS strategy in the field of POPs detection.