title: A capillary gas chromatography/mass spectrometric method for the quantification of hydroxysteroids in human plasma.
abstract: A specific and sensitive methodology for the quantitative determination of hydroxysteroids dehydroepiandrosterone and pregnenolone and their main metabolites in human plasma is described. Hydroxysteroids were extracted using methanol and steroids were further separated by reverse-phase high-performance liquid chromatography, allowing for minimization of the possible chromatographic interferences. Eluted fractions were collected, pooled, and analyzed by gas chromatography-mass spectrometry as trimethylsilyl ether derivatives. The quantification was performed with single-ion monitoring of the highly abundant m/z 129 or m/z 358 fragments. The combination of the chromatographic characteristics to the specific fragments ensured the selectivity and specificity of the method. Under these conditions the method was linear (typical R2 is superior to 0.98 for all hydroxysteroids studied) over the concentration range of 2 x 10(-9) to 10(-6)M with good precision and accuracy.
authors.affiliation: Department of Biochemistry and Molecular Biology, Georgetown University Medical Center, Washington, DC 20057, USA.
authors.forename: S
authors.initials: S
authors.lastname: Diallo
authors.forename: L
authors.initials: L
authors.lastname: Lecanu
authors.forename: J
authors.initials: J
authors.lastname: Greeson
authors.forename: V
authors.initials: V
authors.lastname: Papadopoulos
mesh_terms: D001711:Biotransformation; D002851:Chromatography, High Pressure Liquid; D003687:Dehydroepiandrosterone / Q000097:blood / Q000378:metabolism; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D006801:Humans; D006914:Hydroxysteroids / Q000097:blood* / Q000737:chemistry; D015394:Molecular Structure; D011284:Pregnenolone / Q000097:blood / Q000378:metabolism; D011863:Radioimmunoassay; D015203:Reproducibility of Results; D013053:Spectrophotometry; D013997:Time Factors
chemical_list: D006914:Hydroxysteroids; D003687:Dehydroepiandrosterone; D011284:Pregnenolone