CONTINUOUS-FLOW EXTRACTION OF COLLOIDAL COMPONENTS IN AQUEOUS SAMPLES

In this study we report the development and performance of a system fo r continuous-now extraction of dissolved and colloidal analytes in an aqueous matrix, Initial studies, using a classical segmented-now extra ction procedure, showed poor extraction efficiency for the hydrophobic colloidally dispersed analytes, Insufficient contact between the extr actant and the colloidal constituents seems to be the primary reason f or poor extraction. Improved performance is obtained when mechanical e nergy is added to the system, to effect a forced contact between the s ample and the solvent. This was accomplished by injecting the extracta nt, with a high velocity, into the continuous now of analyte through a narrow-bore nozzle, In this way, the solvent stream is dispersed into fine droplets with high kinetic energies, A region of intense turbule nce is created, which was studied by high-speed photography using puls ed laser fluorescence. Comparison with classical now extraction, using a model sample of colloidal wood resin compounds in water, showed tha t the dissolved components extracted well with both systems, while an extraction enhancement of up to 9 times was experienced with colloidal triglycerides.