Efficient liquid chromatographic analysis of mono-, di-, and triglycerols using silver thiolate stationary phase

We show that the characterization of mono-, di- and triglycerols can be readily accomplished by high performance liquid chromatography (HPLC) with silver(I)-mercaptopropyl modified silica gel, or silver thiolate chromatographic material (AgTCM), which can be used with evaporative light scattering detection (ELSD) or atmospheric pressure chemical ionization mass spectroscopy (APCI-MS). Separation of triglycerols varying by degrees of unsaturation and cis/trans configuration in common oil samples can be achieved using a simple linear gradient of hexane and acetone. In addition to double bonds, AgTCM also displays major selectivity for compounds with different levels of polarity, allowing for efficient separation between mono-, di- and triglycerols. In comparison to conventional reversed phase columns, AgTCM produces simple chromatograms for rapid assessment of degrees of unsaturation and the amount of trans fats in triglycerides, which are central issues to food quality determination. In comparison to previous silver-ion based HPLC separations, AgTCM–HPLC based column offers greatly enhanced stability, inertness, durability, and reproducibility allowing routine coupling of the HPLC with a mass spectrometer for detection.