High-performance liquid chromatography separations coupled with coulometric electrode array detectors: a unique approach to metabolomics.

Metabolomics is the systematic and theoretically comprehensive study of the small molecules that comprise a biological sample, e.g., sera or plasma. The primary analytical tools used in metabolomics are nuclear magnetic resonance and mass spectroscopy. We here address a different tool, high-performance liquid chromatography (HPLC) separations coupled with coulometric electrode array detection. This system has unique advantages, notably sensitivity and high quantitative precision, but also has unique limitations, such as obtaining little structural information on the metabolites of interest and limited scale-up capacity. The system also only detects redox-active compounds, which can be either a benefit or a detriment, depending on the experimental goals and design. Here, we discuss the characteristics of this HPLC/coulometric electrode array system in the context of metabolomics, and then present the method as practiced in our groups.