ATTEMPT FOR AN ONLINE SIZE EXCLUSION CHROMATOGRAPHY GAS-CHROMATOGRAPHY METHOD FOR ANALYZING PESTICIDE-RESIDUES IN FOODS

Advantages and limitations of an on-line SEC-GC method for the analysis of pesticide residues in foods are discussed; results are shown for olive oil, fat extracts of chicken and fish, and lettuce. The method allows automated integration of sample preparation into the GC analysis and eliminates corresponding manual work. It is well suited as a multimethod for analyzing many strongly differing components at the same time, and, as high molecular weight materials are removed, it allows on-column introduction into GC without contaminating the column inlet. On the other hand, SEC is poorly suited to ''thin out'' gas chromatograms, i.e., to eliminate interfering peaks. Detection limits of chlorinated pesticides related to the amount of fat injected were 10-50-mu-g/kg.