Comprehensive two-dimensional liquid chromatography with ultraviolet, evaporative light scattering and mass spectrometric detection of triacylglycerols in corn oil.
An improved comprehensive two-dimensional (LC x LC) HPLC system for the analysis of triacylglycerols was developed. In the first-dimension, a Ag(I)-coated cation exchanger (250 mm x 2.1 mm, 5 microm) was employed with a gradient from 100% MeOH to 6% MeCN in MeOH at 20 microL/min. Using a 10-way valve with two switching loops, 1 min sections of the first-dimension were introduced in the second-dimension consisting of a 30 mm x 4.6 mm C18 (1.8 microm) column with an isocratic mobile phase of methanol-methyl tert-butyl ether (70:30) at 3.0 mL/min. As the second-dimension solvent was stronger than the first-dimension solvent, focusing in the second-dimension took place, leading to better separations than in previously reported analyses in which hexane was the main constituent of the first-dimension eluent. Compounds differing by 2 in their partition number were baseline separated in the second-dimension. Detection took place by UV at 210 nm, evaporative light scattering and (+)-atmospheric pressure chemical ionisation-MS with the latter giving the best results. Corn oil was investigated and 44 compounds could be detected: 34 triacylglycerols (TAGs), 8 oxygenated TAGs, and 2 TAGs containing a trans double bond. Data manipulation allowed the construction of contour plots and the automated calculation of the first- and second-dimension retention times and peak areas. Quantitative results are compared with a fatty acid methyl ester analysis, and with literature data.
Natural Products Chemistry Group, Laboratory of Organic Chemistry, Wageningen University, Dreijenplein 8, 6703 HB Wageningen, The Netherlands.
Elbert J C
EJ
van der Klift
Gabriel
G
Vivó-Truyols
Frank W
FW
Claassen
Frederique L
FL
van Holthoon
Teris A
TA
van Beek
D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003314:Corn Oil / Q000032:analysis* / Q000302:isolation & purification; D008027:Light; D013058:Mass Spectrometry / Q000379:methods*; D012542:Scattering, Radiation; D014280:Triglycerides / Q000032:analysis* / Q000302:isolation & purification
D014280:Triglycerides; D003314:Corn Oil