DETERMINATION OF HYDROPHILE-LIPOPHILE BALANCE OF SOME POLYETHOXYLATED NONIONIC SURFACTANTS BY REVERSED-PHASE THIN-LAYER CHROMATOGRAPHY

A study has been carried out to verify the applicability of RP-TLC to the determination of the HLB values of some polyethoxylated non-ionic surfactants. Our results show that adsorption phenomena do not significantly affect retention and that a linear relation exists between the HLB value and the lipophilicity parameter R(Mo). A deviation from this linear correlation was observed for compounds bearing hydrophilic chains with more than 12-13 ethylene oxide units. These exceptions can be explained in terms of methodological limitations and/or conformational properties. RP-TLC method appears to be a simple, rapid and inexpensive way to rank non-ionic amphiphilic substances.