Bridging the polar and hydrophobicmMetabolome in single-run untargeted liquid chromatography-mass spectrometry dried blood spot metabolomics for clinical purposes

Abstract

Dried blood spot (DBS) metabolite analysis is a central tool for the clinic, e.g., newborn screening. Instead of applying multiple analytical methods, a single liquid chromatography-mass spectrometry (LC–MS) method was developed for metabolites spanning from highly polar glucose to hydrophobic long-chain acylcarnitines. For liquid chromatography, a diphenyl column and a multi-linear solvent gradient operated at elevated flow rates allowed for an even-spread resolution of diverse metabolites. Injecting moderate volumes of DBS organic extracts directly, in contrast to evaporation and reconstitution, provided substantial increases in analyte recovery. Q Exactive MS settings were also tailored for sensitivity increases, and the method allowed for analyte retention time and peak area repeatabilities of 0.1–0.4 and 2–10%, respectively, for a wide polarity range of metabolites (log P −4.4 to 8.8). The method’s performance was suited for both untargeted analysis and targeted approaches evaluated in clinically relevant experiments.