High-temperature separations on a polymer-coated fibrous stationary phase in microcolumn liquid chromatography

Ultrafast Polyphenol Metabolomics of Red Wines Using MicroLC-MS/MS

The taste and quality of red wine are determined by its highly complex mixture of polyphenols and many other metabolites. No single method can fully cover the full metabolome, but even for polyphenols and related compounds, current methods proved inadequate. We optimized liquid chromatography resolution and sensitivity using 1 mm i.d. columns with microLC pumps and compared data-dependent to data-independent (SWATH) MS/MS acquisitions. A high-throughput microLC-MS method was developed with a 4 min gradient at 0.05 mL/min flow rate on a Kinetex C18 column and Sciex TripleTOF mass spectrometry. Using the novel software MS-DIAL, we structurally annotated 264 compounds including 165 polyphenols in six commercial red wines by accurate mass MS/MS matching. As proof of concept, multivariate statistics revealed the difference in the metabolite profiles of the six red wines, and regression analysis linked the polyphenol contents to the taste of the red wines.

Preconcentration of Aromatic Compounds in Aqueous Samples with a Polymer-coated Fiber-packed Capillary and Subsequent Temperature-programmed Elution with Water for Pseudo-2D LC Separations

A bundle of polymer-coated filaments was successfully introduced as an extraction medium for the preconcentration of an aqueous solution of aromatic compounds. The extraction was simply carried out with pumping the aqueous sample solution to the extraction capillary at ambient temperature. The extracted analytes were sequentially eluted with a flow of pure water using temperature-programmed heating of the extraction capillary in an oven. The results clearly suggest that the polymer-coated fiber-packed capillary could be employed in the sample preparation process for the analysis of various aqueous samples. Introducing the fractions eluted from the fiber-packed capillary to a conventional microcolumn liquid chromatography (micro-LC) system via a home-made valve-based modulator, an on-line coupled extraction/separation system was developed and a possibility to a pseudo-two-dimensional (pseudo-2D) LC separation of aromatic compounds in aqueous matrices has also been demonstrated.