Plant Metabolomics: Evaluation of different Extraction Parameters for Nontargeted UPLC-ESI-QTOF-Mass Spectrometry at the Example of white Asparagus officinalis.

The extraction of metabolites turns out to be one of the most important key factors for nontargeted metabolomics approaches as this step can significantly affect the informative value of the successive measurements. Compared to metabolomics experiments of various matrices of bacterial or mammalian origins, there are only few studies, which focus on different extraction methods for plant metabolomics analyses. In this study, various solvent extraction compositions were compared and assessed by using an UPLC-ESI-QTOF-MS strategy. Exemplary, white asparagus (Asparagus officinalis) were used as a low-fat-, low-protein-, high-water-content model commodity with the objective of designing an optimal nontargeted extraction protocol for polar and nonpolar metabolites. Furthermore, the influence of acid addition, mechanical cell disruption methods (ball mill, ultrasonic bath, vortex mixer) and extract stability have been systematically scrutinized, too. The different extraction protocols were compared based on sum of features, sum of peak intensities, sum of peak areas as well as by analyzing individual signals of as many different substance groups as possible in order to obtain a maximum overview.