STIMULATED RAMAN-SPECTROSCOPY FOR THE QUANTITATIVE-DETERMINATION OF ORGANIC-COMPOUNDS

The efficiency of the stimulated Raman scattering (SRS) in liquids is sufficiently high to make the phenomenon useful as a means of chemical analysis. It may be larger than the spontaneous scattering efficiency by many orders of magnitude at high molecular densities. This technique is evaluated for the detection and measurement of organic compounds in liquid solution. With a laser light path of 50 cm, the technique is useful for the non-invasive, real-time remote monitoring of SRS active compounds at the tens of part-per-million or higher level. Direct identification and simultaneous determination of individual chemicals in simple matrices can be attained without sampling, separations or other pretreatment procedures. The. influences of seeding by spontaneous Raman scattering, threshold, exponential gain, saturation, collimated versus focused excitation beams, self-focusing, and photobleaching of fluorescent interferents on analytical figures of merit are discussed.