Determination of stable isotopic enrichment and concentration of glycerol in plasma via gas chromatography-mass spectrometry for the estimation of lipolysis in vivo

Measuring glycerol's rate of appearance into the plasma compartment provide s an excellent estimation of whole-body lipolysis. The glycerol rate of app earance can be calculated by estimating the plasma dilution of continuously infused stable or radioactive isotopes of glycerol. Previously, determinat ion of glycerol stable isotopic enrichment has required either chemical. io nization gas chromatography-mass spectrometry (GC-MS) or electron impact io nization GC-MS in which a fragment containing only a portion of the glycero l molecule was measured. The present method uses tert.-butyldimethylsilyl ( tBDMS) derivatization and electron impact ionization to measure a fragment including the entire glycerol molecule. The method determines concentration and enrichment of plasma glycerol in a simple, precise, and cost-efficient manner, providing a basis from which lipid homeostasis can be assessed. (C ) 2000 Elsevier Science BN. All rights reserved.