Development of GC-MS/MS method with programmable temperature vaporization large volume injection for monitoring of 17 beta-estradiol and 2-methoxyestradiol in plasma

作者：Tsakalof A K^*; Gkagtzis D C; Koukoulis G N; Hadjichristodoulou C S

来源：Analytica Chimica Acta, 2012, 709: 73-80.

DOI：10.1016/j.aca.2011.09.043

• 17 beta-Estradiol
• 2-Methoxyestradiol
• GC-MS/MS
• Steroids
• Pre-eclampsia

Monitoring of estradiol and its metabolites in biological samples is essential for the accurate diagnosis of a number of endocrine diseases. In this study, a sensitive, precise and specific GC-MS/MS method for the quantification of 17 beta-estradiol (17-BE) and its main metabolite, 2-methoxyestradiol (2-MEOE), in plasma was developed and validated. Plasma concentrations of these steroids are currently investigated as diagnostic markers for pre-eclampsia, a systematic disorder of pregnancy and a leading cause of maternal and fetal morbidity and mortality worldwide. %26lt;br%26gt;The method comprised treatment of the plasma sample by protein precipitation and subsequent isolation of steroids by solid phase extraction, derivatization of steroids by trifluoroacetic anhydride and GC-MS/MS analysis of the derivatized steroids. The large volume (10 mu L) injection with the assistance of a Programmed Temperature Vaporization (PTV) injector in solvent split mode allowed a substantial increase in the sensitivity of the method. %26lt;br%26gt;The ion trap MS was operated in optimized Product Ion Scan. By increasing the damping gas flow in the ion trap from the conventional 0.3 mL min(-1) to 2 mL min(-1), ion fragmentation was reduced and the instrument response was enhanced substantially. As a result, mass spectra with predominant molecular ions were acquired and molecular ions of the steroids of interest were used as precursor ions thus increasing specificity of the method. %26lt;br%26gt;Under optimized GC-MS/MS conditions in product ion mode, the Limit of Detection (LOD) of the analyzed steroids ranged from 18.4 pg mL(-1) for 17-BE to 5.5 pg mL(-1) for 2-MEOE (S/N = 3). The instrument response was linear in the investigated concentration range from 0.1 to 10 ng mL(-1) with R-2 %26gt;0.99 for 17-BE and 2-MEOE. The intra-batch accuracy obtained for quality control samples at the concentration levels of 0.1, 1, 3, 7 ng mL(-1) ranged from 94.9% to 109.9% for 17-BE and from 99.9% to 104.5% for 2-MEOE.

• 出版日期2012-1-4