Boosting the Quantitative Inorganic Surface-Enhanced Raman Scattering Sensing to the Limit: The Case of Nitrite/Nitrate Detection.

A high-performance ionic-sensing platform has been developed by an interdisciplinary approach, combining the classical colorimetric Griess reaction and new concepts of nanotechnology, such as plasmonic coupling of nanoparticles and surface-enhanced Raman scattering (SERS) spectroscopy. This approach exploits the advantages of combined SERS/surface-enhanced resonant Raman Scattering (SERRS) by inducing the formation of homogeneous hot spots and a colored complex in resonance with the laser line, to yield detection limits for nitrite down to the subpicomolar level. The performance of this new method was compared with the classical Griess reaction and ionic chromatography showing detection limits about 6 and 3 orders of magnitude lower, respectively.