Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 4/1/1997
Publication Date: N/A
Technical Abstract: Atmospheric pressure chemical ionization mass spectrometry (APCI-MS), a soft ionization technique, has been used with reversed-phase high performance liquid chromatography (RP-HPLC) for qualitative and quantitative analysis of triacylglycerols (TAG) from synthetic and natural mixtures. Separation and analysis were performed on a synthetic mixture of thirty-five TAG, on normal and randomized lard samples, and on normal and interesterified blends of canola oil with cottonseed oil saturates. Qualitative analysis revealed that simple mass spectra were obtained for TAG components, which exhibited only [M-RCOO]**+ fragment ions and protonated molecular ions, [M+H]**+. The amount of unsaturation contained within the fatty acyl chains of the TAG species was the primary factor affecting the relative amounts of [M-RCOO]**+ versus [M+H]**+ ions formed. The qualitative appearance of spectra distinctly affected the integrated areas of TAG species used for quantitation and revealed that response factors were necessary to account for differences in response between TAG species. Response factors were calculated and tested using several approaches. Two methods proved more effective than others: 1) quantitation was based on the calculation of fatty acid response factors from the fatty acid compositions determined by calibrated gas chromatography with flame ionization detection (GC-FID, then these were used to calculate TAG response factors; and 2) empirical response factors were obtained from randomized samples and applied to non randomized (normal) samples. Response factors thus calculated produced results which gave good agreement to expected results.