Measurement of glucose and fructose in clinical samples using gas chromatography/mass spectrometry.
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.
Wahjudi
Paulin N
PN
Los Angeles Biomedical Research Institute, 1124 West Carson Torrance, CA 90502, USA.
Patterson
Mary E
ME
Lim
Shu
S
Yee
Jennifer K
JK
Mao
Catherine S
CS
Lee
W-N Paul
WN
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
D004040:Dietary Carbohydrates; D005632:Fructose; D005947:Glucose