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 sub strate 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 (p olyester and cellulose) have been measured as a function of the aqueous sod ium dodecylsulfate (SDS) micelle concentration in the mobile phase. The par tition coefficients of two soil models between the fiber substrate and mice lles (P-sm), between the fiber substrate and water (P-sw)and between micell es and water (P-mw) were determined with the application of the partition e quation for the pseudophase liquid chromatography to this system. The P-sm and P-sw values were larger far the polyester system than for cellulose whi ch showed that oily soil is much more difficult to remove from polyester th an from cellulose. It produced a tendency similar to the effects of fiber s ubstrates on oily soil removal and on oily soil redeposition that have been studied using radiotagging and other methods. This liquid chromatography t echnique may be used to investigate the equilibrium behavior during soil re moval and for the soil redeposition on a substrate in a detergent solution.