A Novel Strategy for Rapid Detection of Bacteria in Water by the Combination of Three-dimensional Surface-enhanced Raman Scattering (3D SERS) and Laser Induced Breakdown Spectroscopy (LIBS)

In this study, a novel strategy based on the combination of 3D SERS and LIBS was developed for qualitative and quantitative detection of bacteria. SERS-active Ag nanoparticles (AgNPs) were prepared by an improved in situ synthesis method, and reproducible SERS spectra of bacteria were obtained by natural evaporation of a droplet of the in situ synthesized sample. Four types of bacteria were classified via principal component analysis (PCA) and hierarchy cluster analysis (HCA). LIBS acted as a quantitative technique for bacterial detection based on the intracellular mineral cations, and bacteria could be detected in a linear range of 5 × 10-5 × 10 CFU mL, with recovery values ranging from 81.0% to 101.7%. The whole detection process including sample preparation and detection could be completed in approximately 30 min. With short assay time and simple operation, the proposed strategy has showed great potential for bacterial analysis.