Influence of secondary interactions on high performance size exclusion chromatography. Application to the fractionation of landfill leachates

Abstract

The leachates from municipal landfills are characterised by the complex chemical distribution and wide molecular weights range of their constituents. We have designed a high performance size exclusion chromatography method to take into account these two aspects. By using eluents of low ionic strength, electrostatic interactions between the eluted molecules and the negative sites of the stationary phase are enhanced. Thus, the compounds are eluted mostly according to their physico-chemical properties. Contrarily, using eluents of high ionic strength allows eliminating most of these electrostatic interactions which, in turn, permits to estimate the molecular weights, since steric exclusion is then the dominating mechanism of separation. A spec- troscopic fingerprint may also be determined through multidetection (UV absorption, fluorescence and evaporative light scatter- ing detection) coupled on line which allows to sort out the compounds into a few number of families.