Volatile carboxylic acid profiling in physiological fluids

Many inborn errors of metabolism are characterized by an increase in the concentrations of various carboxylic acids in blood and urine. For example, the metabolic disorders propionic acidemia [ 11, methylmalonic aciduria [ 2,3], maple syrup urine disease [4], isovaleric acidemia [ 41 and glutaric aciduria type II [ 5,6] show increased amounts of volatile carboxylic acids in blood or urine. Procedures for the profiling and/or quantitation of these carboxylic acids require their isolation from blood or urine by vacuum distillation [6], extraction [ 7,8] , silicic acid absorption [ 91 or ion-exchange chromatography [lo] prior to gas chromatographic (GC) or gas chromatographic-mass spectrometric (GC-MS) analysis. These procedures are time-consuming and may result in losses of the more volatile acids. We have developed a rapid procedure for the profiling of volatile carboxylic acids in blood and urine that involves neither extraction or derivatization of the carboxylic acids prior to GC analysis.