SOLVENT EXTRACTION-FLOW INJECTION WITHOUT PHASE-SEPARATION THROUGH THE USE OF THE DIFFERENTIAL FLOW VELOCITIES WITHIN THE SEGMENTED FLOW

A simple and robust flow injection extraction system has been develope d. The system exploits the wetting film of the organic phase which for ms on the walls of the hydrophobic Teflon tubing. This wetting film is stationary and thus reduces the average linear velocity of the organi c flow. Any component extracted into the organic phase requires more t ime to pass through the extraction coil than the unextracted component s. Using organic solvents such as hexanol, which have a high viscosity and low interfacial tension, the differential flow velocities can yie ld a separation in time between unextracted and extracted components. After the separation is complete, methanol addition homogenizes the se gmented flow prior to its passage through the flow cell of an absorban ce detector. Thus the need for a phase separator has been eliminated. Large aqueous-to-organic phase ratios, high flow rates, and long extra ction coils enhance the resolution between the unextracted and extract ed components. The active components in motion sickness tablets were d etermined with an analytical precision of 2.5-4.0% and a throughput of 12 analyses/h.