title: Determination of benzoic acid in serum or plasma by gas chromatography-mass spectrometry (GC/MS).
abstract: Nonketotic hyperglycinemia (NKH), a metabolic disorder due to defects in the glycine cleavage system, leads to the accumulation of toxic levels of glycine. Glycine levels in these patients may be lowered by sodium benzoate treatment. Benzoic acid binds to glycine to form hippurate, which is subsequently eliminated through the kidneys. At high concentrations, hippuric acid can crystallize in the kidneys and cause renal failure. Therefore, it is desirable to have benzoic acids concentrations within a therapeutic range. In the gas chromatography method described, the drug from the acidified serum or plasma sample is extracted using ethyl acetate. The organic phase containing drug is separated and dried under a stream of nitrogen. After trimethylsilyl derivatization, benzoic acid analysis is done on a gas chromatograph mass spectrometer. Quantitation of the drug in a sample is achieved by comparing responses of the unknown sample to the responses of the calibrators using selected ion monitoring. Benzoic acid D(5) is used as an internal standard.
authors.affiliation: Department of Pathology and Laboratory Medicine, Children's Mercy Hospitals and Clinics, Kansas City, MO, USA.
authors.forename: Jeff M
authors.initials: JM
authors.lastname: Knoblauch
authors.forename: David K
authors.initials: DK
authors.lastname: Scott
authors.forename: Laurie D
authors.initials: LD
authors.lastname: Smith
authors.forename: Uttam
authors.initials: U
authors.lastname: Garg
mesh_terms: D019817:Benzoic Acid / Q000097:blood* / Q000627:therapeutic use; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006801:Humans; D020158:Hyperglycinemia, Nonketotic / Q000097:blood / Q000188:drug therapy; D015203:Reproducibility of Results
chemical_list: D019817:Benzoic Acid