Pyroglutamate (5-oxoproline) measured with hydrophilic interaction chromatography (HILIC) tandem mass spectrometry in acutely ill patients

Abstract

Background Pyroglutamic acid (PGA) is challenging to quantify in plasma and is a rare cause of metabolic acidosis that is associated with inherited disorders or acquired after exposure to drugs. Method We developed a hydrophilic interaction liquid chromatography tandem mass spectrometry method with a short analysis time. We established a reference interval and then measured PGA in acutely ill patients to investigate associations with clinical, pharmaceutical and laboratory parameters. Results The assay limit of the blank was 0.14 μmol/L and was linear to 5000 μmol/L with good precision. In-source formation of PGA from glutamate and glutamine was avoided by chromatographic separation. The PGA..