SOLVENT EXTRACTION-SEQUENTIAL INJECTION WITHOUT SEGMENTATION AND PHASE-SEPARATION BASED ON THE WETTING FILM FORMED ON A TEFLON TUBE WALL

A novel solvent extraction-flow/sequential injection system was develo ped, The system is based on the film-forming characteristics of an org anic phase on a Teflon tube wall, The coating solvent, aqueous sample solution and eluting solution, which were separated by air segments, w ere sequentially aspirated into a Teflon extraction coil, A stationary organic wetting film was formed on the wall of the extraction coil, T he extractable substances in the following aqueous solution were extra cted into the wetting film and remained on the tubing wall, The extrac ted analytes were then washed out by microlitre amounts of eluting sol ution and the absorbance of the eluting solution was measured in a flo w-through sandwich cell, The extractable and unextractable components can be efficiently separated and simultaneously determined, The need f or a segmenter and a phase separator has been eliminated and the consu mption of organic solvents has been reduced to microlitres, The system can be operated at sample frequencies of 30 and 10 h(-1) with enrichm ent factors of 30 and 150, respectively.