Clinical Applications of Mass Spectrometry

Volume 603 of the series Methods in Molecular Biology pp 423-431


Urine Organic Acid Analysis for Inherited Metabolic Disease Using Gas Chromatography-Mass Spectrometry

  • Patricia M. JonesAffiliated withDepartment of Pathology, University of Texas Southwestern Medical Center and Children’s Medical Center
  • , Michael J. BennettAffiliated withDepartment of Pathology and Laboratory Medicine, University of Pennsylvania and Children’s Hospital of Philadelphia

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Urine organic acid analysis is an essential component of the workup of the patient suspected to have an inborn error of metabolism (IEM). Urine contains several hundred different organic acids, which arise from a multitude of different sources including both normal and abnormal metabolism. They may also arise from drugs and drug metabolism or from xenobiotics and dietary supplements. In addition to the diagnosis of inborn errors of metabolism, the identification of organic acids in a urine sample has a wide range of potential applications, including toxicology and poisonings. The method described below extracts the acidic fraction from urine samples, derivatizes the extracted compounds, and identifies intermediate metabolites by GC-MS. The method utilizes electron impact ionization gas chromatography-mass spectrometry (GC-MS) with total ion collection.

Key words

Organic acids inborn errors of metabolism gas chromatography-mass spectrometry