Innovative strategy on improved surface-enhanced Raman scattering sensing by using plasmon-activated water dissolving analyte

High surface-enhanced Raman scattering (SERS) enhancement is generally accompanied by low signal reproducibility. Thus, various complicated technologies focusing on SERS-active substrates were developed to overcome these limitations. On the other hand, innovatively treated plasmon-activated water (PAW) with properties distinct from those of untreated bulk water was previously reported. Herein, we propose an alternative promising strategy to obtain overall improved SERS performances of analyte solutions prepared using PAW instead of conventional deionized water (DIW). Interestingly, SERS signals were higher, but the corresponding relative standard deviations were lower for the model molecules of rhodamine 6G and methyl blue, with different concentrations prepared in PAW compared to those prepared in DIW. Moreover, these overall improved SERS performances were observed when detecting the pesticides acetamiprid (AC) and imidacloprid (IM) prepared in PAW, compared to those prepared in DIW. Experimental results indicated that the limit of detection (LOD) was 5 ppb (100 ppb based on DIW) for AC prepared using PAW. Moreover, the LOD was 10 ppb for IM prepared using PAW. These extremely low values of LOD detected for AC and IM were comparable to and even better than other SERS detection methods based on solutions prepared using organic solvents or organic solvent/water systems. Moreover, using PAW to dissolve analyte provides an innovative method in SERS studies.