PNNL

Abstract

Metabolites have essential roles in microbial communities, including as mediators of nutrient and energy exchange, cell-to-cell communication, and antibiosis. While improvements are still needed in general methods for broad identification and quantification of the metabolome, the detection and characterization of hundreds of metabolites in typical studies is now common. However, detecting and quantifying metabolites and other chemicals in samples having extremes in salt or mineral content using mass spectrometry-based methods remains a significant challenge. Here we report a suite of chemoselective tags for mass spectrometry-based analysis of metabolites and other chemicals in matrices containing up to 2 molar total dissolved salts. The method, MetFish, is applicable to molecules containing amine, carboxylic acid, carbonyl, or hydroxyl functional groups, and can be integrated into targeted or untargeted analysis pipelines. In targeted analyses, MetFish provided limits of quantification as low as 1 nM, broad linear dynamic ranges (up to 5-6 orders of magnitude) with excellent linearity, and low median inter-day reproducibilities (e.g. 2.6%). We applied MetFish in metabolomics analyses of microbial consortia, quantifying amino acid dynamics in the exo-metabolome during community succession; in situ in a native prairie soil, whose exo-metabolome was isolated using a hypersaline extraction; and in input and produced fluids from a hydraulically fractured well, identifying dramatic changes in the exo-metabolome over time in the well