Ultrasensitive surface-enhanced Raman scattering detection of biological pollutants by controlled evaporation on omniphobic substrates.

A simple and highly sensitive method, combining slippery liquid-infused porous substrates and surface-enhanced Raman spectroscopy (SLIPSERS) was used to detect biological pollutants at very low concentrations. Two commonly used rodenticides (brodifacoum and sodium monofluoroacetate) with long biological half-lives were selected as analytes. The SLIPSERS platform gives reproducible SERS enhancement and this allows "label-free" SERS detection of these environmental pollutants. Analyte ions were detected down to a concentration of 10 M for brodifacoum and 10 M for sodium monofluoroacetate. The limit of detection, limit of quantification and limit of linearity for brodifacoum are 10 M, 10 M and 10 M respectively. The SLIPSERS method uses a physical process to significantly increase analyte concentration, and SERS enhancement and therefore can be generally applied to a range of environmental pollutants. The method can be successfully used for ultra-sensitive detection of several chemical and biological contaminants and meet the emerging needs of environmental monitoring and food safety analysis.