THE STRUCTURE AND CHROMATOGRAPHIC PROPERTIES OF POLY(ETHYLENE GLYCOL)20M LAYER ON THE SURFACE OF A DIATOMACEOUS-EARTH TYPE SUPPORT

The properties of poly(ethylene glycol) 20M (PEG 20M) coated on the hy droxylated surface of Chromaton N AW were investigated by inverse gas chromatography. It was found that the solid form of PEG 20M exhibits p artition as the retention mechanism even below its melting range. The contribution of adsorption to the specific retention volume was also d etermined. It was demonstrated that inverse gas chromatography establi shes the existence of a polymer surface layer but precise determinatio n of its thickness is difficult. The limitation of the applicability o f inverse gas chromatography results from the structure of the investi gated surface layer which is thin and not coherent so that solute mole cules can penetrate it.