title: Simple isotope dilution assay for propionic acid and isovaleric acid.
abstract: A gas chromatographic-mass spectrometric method is described for the assay of propionic acid and of isovaleric acid in physiological fluids by isotope dilution. The acids are derivatized to the pentafluorobenzyl esters to decrease volatility to render them suitable for GC-MS analysis. The following reference values were found. Propionic acid: plasma 0.54 +/- 0.38 mumol/l (n = 13, range 0.03-1.38 mumol/l), urine 1.7 +/- 1.6 mumol/mmol creatinine (n = 9, range 0.1-4.9 mumol/mmol creatinine). Isovaleric acid: plasma 0.89 +/- 0.93 mumol/l (n = 10, range 0.01-3.03 mumol/l), urine 0.38 +/- 0.51 mumol/mmol creatinine (n = 10, range 0.01-1.70 mumol/mmol creatinine).
authors.affiliation: Department of Pediatrics, New York University Medical Center, NY 10016, USA.
authors.forename: K
authors.initials: K
authors.lastname: Arthur
authors.forename: F A
authors.initials: FA
authors.lastname: Hommes
mesh_terms: D003404:Creatinine / Q000652:urine; D003903:Deuterium; D004952:Esters; D005464:Fluorobenzenes; D008401:Gas Chromatography-Mass Spectrometry / Q000295:instrumentation / Q000379:methods; D045782:Hemiterpenes; D006801:Humans; D007201:Indicator Dilution Techniques; D008661:Metabolism, Inborn Errors / Q000235:genetics; D010421:Pentanoic Acids / Q000032:analysis* / Q000097:blood / Q000652:urine; D011422:Propionates / Q000032:analysis* / Q000097:blood / Q000652:urine; D012016:Reference Values; D005466:Fluorocarbons
chemical_list: D003404:Creatinine; D003903:Deuterium; D004952:Esters; D005464:Fluorobenzenes; D045782:Hemiterpenes; D010421:Pentanoic Acids; D011422:Propionates; C025063:pentafluorobenzyl bromide; D005466:Fluorocarbons; C008216:isovaleric acid; C029658:propionic acid