The dimers in the heated olestra were fractionated with preparative thin layer chromatography, while the dimers contained in the heated mixture of olestra and soybeanoil were fractionated with preparative size exclusion chromatography (SEC). Fractionscontaining suspected dimers were transesterified. The methyl ester fatty acid dimers wereseparated with capillary gas chromatography and tentatively identified based on their retention times relative to methylated dimer fatty acid standards