title: Measurement of glucose and fructose in clinical samples using gas chromatography/mass spectrometry.
abstract: OBJECTIVE
  The impact of increased fructose consumption on carbohydrate metabolism is a topic of current interest, but determination of serum level has been hindered due to low concentration and interference from serum glucose. We are reporting a method for the quantification of glucose and fructose in clinical samples using gas chromatography/mass spectrometry (GC/MS). The accuracy and precision of GC/MS and an enzymatic assay were compared.
  
  
  METHODS
  Mass spectrometry fragmentation patterns of methyloxime peracetate derivatized aldose and ketose were determined. Unique fragments for glucose and fructose were used for quantitative analysis using isotope labeled recovery standards.
  
  
  RESULTS
  Methyloxime peracetate derivatives of glucose and fructose showed characteristic loss of acetate (M-60) or ketene (M-42) under chemical ionization (CI). Under electron impact (EI) ionization, a unique C1-C2 fragment of glucose was formed, while a C1-C3 fragment was formed from keto-hexoses. These unique fragments were used in the quantitative assay of glucose and fructose in clinical samples. In clinical samples, the GC/MS assay has a lower limit of detection than that of the enzymatic assay. In plasma samples from patients evaluated for diabetes the average serum glucose and fructose were 6.19+/-2.72 mM and 46+/- 25.22 microM. Fructose concentrations in many of these samples were below the limit of detection of the enzymatic method.
  
  
  CONCLUSIONS
  Derivatization of aldose and ketose monosaccharides to their respective O-methyloxime acetates for GC/MS analysis is a facile method for determination of serum/plasma glucose and fructose samples.
authors.affiliation: Los Angeles Biomedical Research Institute, 1124 West Carson Torrance, CA 90502, USA.
authors.forename: Paulin N
authors.initials: PN
authors.lastname: Wahjudi
authors.forename: Mary E
authors.initials: ME
authors.lastname: Patterson
authors.forename: Shu
authors.initials: S
authors.lastname: Lim
authors.forename: Jennifer K
authors.initials: JK
authors.lastname: Yee
authors.forename: Catherine S
authors.initials: CS
authors.lastname: Mao
authors.forename: W-N Paul
authors.initials: WN
authors.lastname: Lee
mesh_terms: D050260:Carbohydrate Metabolism; D004040:Dietary Carbohydrates / Q000378:metabolism; D005632:Fructose / Q000097:blood* / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry / Q000295:instrumentation / Q000379:methods*; D005947:Glucose / Q000737:chemistry / Q000378:metabolism*; D006801:Humans
chemical_list: D004040:Dietary Carbohydrates; D005632:Fructose; D005947:Glucose