MPSS - A NEW SCATTERING TECHNIQUE FOR SENSITIVE MEASURING OF THE TOTAL ABSORPTION OF FLUIDS

Optical methods are appropriate tools to detect organic micro-pollutan ts in fluids. A simple technique is introduced which uses radiation sc attered elastically by the fluid. Two different signals are measured: (1) the linear or conventional scattering (CS), which occurs at short pathlengths of the incidence radiation in the fluid, and (2) the multi path-saturation scattering (MPSS) originating at long pathlengths, e.g ., in multipath-reflection cuvettes, where the radiation is fully abso rbed by the fluid, A relation between the scattering signals and the t otal absorption coefficient of the fluid is theoretically derived. A s imple experiment is performed that takes into consideration the scatte ring of distilled water polluted with azobenzene and quinine-sulfate. A xenon lamp and a nitrogen laser are used to generate CS and MPSS. Th e scattering ratio CS/MPSS yields the total absorption directly. In co mparison to the conventional absorption technique, CS/MPSS is characte rized by a higher sensitivity.