Determination of α-tocopherol in different biological samples by GC-MS without derivatization

Abstract

A method has been developed to determine the levels of α-tocopherol in human plasma and colon tissue using gas chromatography with mass spectrometric detection. The samples were acquired from 27 patients with Crohn’s disease. Samples were deproteinized and α-tocopherol was obtained using a two-step extraction and measured by GC-MS without prior derivatization. The analytical parameters of the method were satisfactory: the intra-day and inter-day coefficients of variation were below 7% and quantitative recoveries range between 92.2-100.5%. The method shows an excellent linear range from 0.6-64.3 μmol/L. The median measured α-tocopherol concentration in human plasma was 21.6 μmol/L and in healthy colon tissue and tissue affected by Crohn’s disease was 26.5 nmol/mg and 34.9 nmol/mg, respectively. We did not find any statistically significant correlation or differences between the α-tocopherol content in plasma and tissue. Overall, our method has potential to be easily implemented in special studies for monitoring α-tocopherol as a biomarker of oxidative stress.