Direct wine analysis was used to determine the molecular weight of the components and their variable content across the 5 samples in this study was observed. This work demonstrates the utility of analyzing complex mixtures without prior sample preparation by making use of the separation of HPLC combined with the High Resolution Accurate Mass (HRAM) of the Q Exactive quadrupole Orbitrap mass analyzer. The combination of these techniques provides a robust and confident means of profiling complex mixtures as well as successful identification of detected components.

The combination of Orbitrap technology with a linear ion trap has become an established platform for high resolution, accurate mass LC-MSn analysis. The high resolving power, mass accuracy and dynamic range of the Orbitrap analyzer allow rigorous characterization of complex mixtures even in the absence of precursor ion mass selection. We now describe the development of a non-hybrid mass spectrometer comprising of an atmospheric-pressure ion source (API) and a standalone Orbitrap mass analyzer.

We demonstrate a complete analytical metabolomic workflow including (1) data acquisition using a high resolution accurate mass instrument that is equipped with a Higher Energy Collisional Dissociation (HCD) cell and coupled to a high pressure LC (Figure 1), (2) metabolite differential abundance analysis, and (3) structural elucidation of relevant metabolites using accurate mass and HCD fragmentation information to highlight the component differences between green and black tea.

A platform using Dionex ion chromatography (IC) coupled to triple quadrupole mass spectrometry (MS) was developed to measure various metabolites in Brassica napus seeds. The IC tandem mass spectrometry (IC-MS/MS) technique provides a good tool to identify and quantify metabolites in a complex matrix.

Here, the author describes an ion-exchange system that provides good separation of the polar metabolities with on-line desalting to allow MS detection. This technique will allow studies of key metabolites that do not separate well on traditional reversed-phase columns. Some ionic metabolites may be positional isomers adjacent to each other in a synthetic pathway and as such, are isobaric. In such cases, MS is not sufficient to differentiate the two compounds. There is clearly a need for adequate separation techniques for isomeric metabolites.