High-throughput direct-infusion ion trap mass spectrometry: a new method for metabolomics.

A fast method was developed to directly infuse raw plant extracts into a linear ion trap mass spectrometer, using the ion trap to isolate and fragment as many ions as possible from the extract. The full mass spectra can be analysed by multivariate statistics to determine discriminating ions, and the fragmentation data allows rapid classification or identification of these ions. The methodology was used to screen a wide range of strains of endophytic fungi in perennial ryegrass seeds for differences in metabolic profiles. The results show that this newly developed methodology is able to determine discriminating ions that can be present in very low concentrations. It also yielded sufficient fragmentation data to classify or identify the discriminating ions.