The elucidation of the mechanism for oily soil removal using liquid chromatography with a fiber powders column

A liquid chromatography technique using a column packed with fiber powders has been introduced for the study of detergency from a physicochemical view point of surfactants involved when oily soils are removed from a fiber substrate into aqueous detergent solution in a state almost without mechanical and/or hydrodynamic actions. The retention volumes of two oily soil models (CI Solvent Yellow 5 and CI Solvent Yellow 14) on two stationary phases (polyester and cellulose) have been measured as a function of the aqueous sodium dodecylsulfate (SDS) micelle concentration in the mobile phase. The partition coefficients of two soil models between the fiber substrate and micelles (P-sm), between the fiber substrate and water (P-sw)and between micelles and water (P-mw) were determined with the application of the partition equation for the pseudophase liquid chromatography to this system. The P-sm and P-sw values were larger far the polyester system than for cellulose which showed that oily soil is much more difficult to remove from polyester than from cellulose. It produced a tendency similar to the effects of fiber substrates on oily soil removal and on oily soil redeposition that have been studied using radiotagging and other methods. This liquid chromatography technique may be used to investigate the equilibrium behavior during soil removal and for the soil redeposition on a substrate in a detergent solution.