Determination of steroid hormones in human plasma by GC-triple quadrupole MS.

A fast and sensitive GC-MS/MS method is proposed to determine pregnenolone, dehydroepiandrosterone (DHEA), testosterone and dihydrotestosterone from human plasma. Steroids were extracted by liquid/liquid extraction, and derivatized with N-methyl-N-trimethylsilyl-trifluoracetamide. Electron ionization at 30eV was applied to generate high abundant precursor ions. Specific precursor/product transitions were generated a priori for each compound of interest and these assays were then used to selectively detect and quantify these steroids. Using the selected reaction monitoring mode, detection limits in the pg/ml (subnmol/l) range could be achieved for all four steroid compounds. The method was validated for imprecision, and recovery and applied in a pilot study in patients with hypercholesterolemia. Associations of increased cholesterol biosynthesis and low testosterone and dihydrotestosterone concentrations were found.