Study of the film formation process in liquid-liquid extraction flow injection analysis

The behaviour of a thin film of an organic solvent on the walls of the extraction coil in a continuous liquid-liquid extraction flow system was studied using a computer-controlled fast-recording on-tube photometric detection system (approx. 3 ms time resolution). A single-loop injector was employed to introduce precise, reproducible volumes (Sr < 2%) of one phase into the continuous stream of the other as a segmented volume standard. The film thickness Df, ranging from 1 to 20 μm for a 0.7 mm teflon tube, was calculated from the segment lengthening at a different chloroform flow rates and was found to obey a polynominal dependence on the linear flow rate, df = f(uα), where α < 1.