title: Quantification of endogenous steroids in human urine by gas chromatography mass spectrometry using a surrogate analyte approach.
abstract: Providing "real blank sample" is a problem in determination of endogenous steroids in complex matrices. A new quantification strategy is proposed in the present study, which is based on using isotope-labeled steroids instead of natural steroids for constructing calibration line. This approach is called surrogate analyte and it is shown that its accuracy is better than some of the previously described methods at low concentrations and comparable to standard addition method at medium and high concentration levels. The method was fully validated to satisfy the ICH criteria and it was applied for determination of endogenous steroids in several urine samples.
authors.affiliation: Department of Medicinal Chemistry, Faculty of Pharmacy and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences, Tehran 14174, Iran.
authors.forename: Reza
authors.initials: R
authors.lastname: Ahmadkhaniha
authors.forename: Abbas
authors.initials: A
authors.lastname: Shafiee
authors.forename: Noushin
authors.initials: N
authors.lastname: Rastkari
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Khoshayand
authors.forename: Farzad
authors.initials: F
authors.lastname: Kobarfard
mesh_terms: D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006801:Humans; D007553:Isotope Labeling; D011786:Quality Control; D012015:Reference Standards; D013256:Steroids / Q000652:urine*; D013739:Testosterone / Q000652:urine
chemical_list: D013256:Steroids; D013739:Testosterone