Nitrate ion detection in aerosols using morphology-dependent stimulated Raman scattering

A nitrate ion concentration of 5×10−5 M has been detected in ∼180 μm diam aqueous aerosols using morphology-dependent stimulated Raman scattering (MDSRS). This low concentration was detected by allowing the droplet size to be tuned during an experiment. Comparison of the experimental results with the MDSRS gain equation shows that it may be possible to detect concentrations a factor of ten lower.