ANALYSIS OF GENETICALLY-MODIFIED CANOLA VARIETIES BY ATMOSPHERIC-PRESSURE CHEMICAL-IONIZATION MASS-SPECTROMETRIC AND FLAME IONIZATION DETECTION

Canola oil triacylglycerols from genetically modified canola lines wer e conclusively identified by reverse phase HPLC coupled with atmospher ic pressure chemical ionization mass spectrometric (APCI-MS) detection . APCI-MS is a soft ionization technique, which gave simple spectra fo r triacylglycerols. Spectral identification of the triacylglycerols wa s based on the diacylglycerol fragments and on the protonated molecula r ion [M+H](+), except trisaturates which gave no [M+H](+). Triacylgly cerols were identified and quantitated in normal, high stearic acid an d high lauric acid canola varieties by the RP-HPLC/APCI-MS technique. The LC/APCI-MS identification of canola oil triacylglycerols allowed t heir quantitation by reverse phase HPLC coupled with a commercial flam e ionization detector (FID). There was agreement between fatty acid co mposition obtained by LC/APCI-MS and LC-FID. However, the triacylglyce rol resolution obtained by LC/APCI-MS, was superior to LC-FID in the q ualitative identification of triacylglycerols present in amounts even below one percent. The oils of the modified canola varieties, compared to typical canola oil, contained increased content of triacylglycerol s known to be more oxidatively stable like stearoyloleoyllinoleoyl, di stearoyllinoleoyl, stearoyldioleoyl and distearoyloleoyl glycerols in high stearic acid canola oil and dilauroyllinoleoyl, dilauroyloleoyl a nd lauroyldioleoyl glycerols in high lauric acid canola oil. These oil s contained fewer linolenate-containing triacylglycerols known to decr ease oxidative stability. The LC/APCI-MS technique gave better resolut ion of, and quantitation of triacylglycerols in the canola oils, than the LC/FID. However, the LC/FID system gave satisfactory analyses suit able for many research programs, like the development of genetically m odified canola varieties with oils of improved oxidative stability.