Determination of total cholesterol and glucose in human serum by isotope dilution mass spectrometry

Accurate methods for determination of total cholesterol and glucose in human serum by isotope dilution mass spectrometry (IDMS) have been studied to establish the accuracy of analytical methods in clinical laboratories. We describe here (1) gas chromatography/mass spectrometric procedure after converting the compounds to the volatile derivatives, (2) off-line liquid chromatography/mass spectrometric (LC/MS) method using electron impact or chemical ionization mass spectrometry, and (3) on-line LC/MS method using atmospheric pressure ionization or plasmaspray (discharge-assisted thermospray) LC/MS interface. (author)