High-performance anion-exchange chromatography using on-line electrolytic eluent generation for the determination of more than 25 intermediates from energy metabolism of mammalian cells in culture

In this work, we present an improved method for the determination of a wide range of intracellular metabolites from mammalian cells by anion-exchange chromatography. The analysis includes the measurement of intermediates from glycolysis and tricarboxylic acid cycle as well as several additional nucleotides and sugar nucleotides. The use of an electrolytic on-line eluent generation device made the method highly convenient, reliable and prone to errors. Due to short delay times of the eluent generator, rapid KOH gradient changes could be applied to improve separation and to speed up elution. Suppressed conductivity and UV in series was used for detection. The detection wavelength of the UV detector was switched from 220 to 260 nm during the elution for a more selective signal depending on the absorption of analytes. Standards from more than 50 metabolites of major cellular pathways were chromatographically tested and compared to chromatograms from extraction samples of Madin–Darby canine kidney (MDCK) and BHK21 cells. A validation for most substances was performed. Detection limits were below the micromolar range and the coefficient of correlation (R2) was above 0.99 for most analytes. Working ranges were between 0.125–3.875 and 4.5–139.5 μM. Sample pH had a major impact on the quantification of several metabolites, but measurements were robust within a pH range of 6.5–9.0.