An improved GC-MS method in determining glycerol in different types of biological samples

Glycerol is an important compound participating in the lipid metabolism and energy conversion of body. Its level, especially in the blood circulation, has been considered as an index in assessing the triglycerides level, fat mobilization and potential risk of hyperlipidemia. In this gas chromatography mass spectrometry (GC-MS) method, 1,2,3-butanetriol was selected as an internal standard instead of isotope labeled glycerol. The internal standard and sample were derivatized by trimethylsilyl imidazole. The glycerol and internal standard derivatives in the sample were measured by a selected ion monitor mode of GC-MS. The sensitivity and repeatability of this method were examined by analyzing glycerol in eleven different types of biological tissue and fluid samples. The glycerol level in the measured mouse plasma sample was at 11.71±0.48μg/mL, while it was in a range of 0.15±0.01 (brain) to 0.39±0.02μg/mg (liver) in the tissue samples. It was 27.06±0.12 and 1.60±0.04μg/mL in the tested human blood and urine samples, respectively. Also, the glycerol recoveries of all samples were higher than 80% and over 90% for the fluid samples, especially. With the satisfactory repeatability and recovery and non-isotope internal standard, the GC-MS method could be a reliable technique in monitoring the glycerol status of biological samples regardless of whether they are from a study in which isotope labeled glycerol or other stable isotope materials were involved.