Determination of N-acetylneuraminic acid by gas chromatography-mass spectrometry with a stable isotope as internal standard.
N-Acetylneuraminic acid was determined by gas chromatography-mass spectrometry using selected ion-monitoring technique with N-[2H3]acetylneuraminic acid as an internal standard. M-COOTMS fragments at m/z 624 of trimethylsilyl derivatives of N-acetylneuraminic acid and at m/z 627 of that of the internal standard were used as monitoring ions. The standard curve obtained was linear in the range of over 10(3), and the lower limit for quantitation was estimated to be a few hundred picograms. This method was used to measure total N-acetylneuraminic acid in the plasma of healthy humans and patients with lung cancer. The total N-acetylneuraminic acid level in the plasma was two to three times higher in the patients than in controls. A few hundred nanoliters of plasma was sufficient for the analysis. The mass fragmentogram of plasma gave a good signal/noise ratio, and measurements were very specific, accurate, and reproducible.
D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D008175:Lung Neoplasms / Q000097:blood*; D019158:N-Acetylneuraminic Acid; D012015:Reference Standards; D012794:Sialic Acids / Q000097:blood* / Q000592:standards; D014297:Trimethylsilyl Compounds
D012794:Sialic Acids; D014297:Trimethylsilyl Compounds; D019158:N-Acetylneuraminic Acid