title: Extractive ethoxycarbonylation in high-temperature gas chromatography-mass spectrometry based analysis of serum estrogens.
abstract: A comprehensive gas chromatography-mass spectrometry (GC-MS)-based profiling was developed as a practical assay for quantification of 18 endogenous estrogens in serum samples. The present GC-MS method was conducted with the two-phase extractive ethoxycarbonlyation (EOC) of the phenolic hydroxy groups of estrogen with ethyl chlorformate combined with the non-polar n-hexane extraction. The subsequent perfluoroacylation of aliphatic hydroxy groups with pentafluoropropionyl anhydride (PFPA) was conducted. The serum samples were separated through a high temperature GC column (MXT-1) within an 8-min run and analyzed in selected-ion monitoring mode with good chromatographic properties for 18 estrogens as their EOC-PFP derivatives. The limit of quantification (LOQ) was 0.025-0.10 ng/mL for most estrogens analyzed except for E3 and 2-OH-E3 (0.5 ng/mL each). The devised method was found to be linear over a 10(3)-fold concentration range with a correlation coefficient (r(2)>0.992), whereas the precision (% CV) and accuracy (% bias) ranged from 3.1 to 16.3% and from 93.5 to 111.1%, respectively. Decreased 2-methoxy-17β-estradiol levels were confirmed in patients with preeclampsia than healthy pregnant women. This technique can be used for a clinical diagnosis as well as understanding the pathogenesis in estrogen-related disorders.
authors.affiliation: Future Convergence Research Division, Korea Institute of Science and Technology, Seoul, South Korea.
authors.forename: Ju-Yeon
authors.initials: JY
authors.lastname: Moon
authors.forename: Se Mi
authors.initials: SM
authors.lastname: Kang
authors.forename: Myeong Hee
authors.initials: MH
authors.lastname: Moon
authors.forename: Jongki
authors.initials: J
authors.lastname: Hong
authors.forename: Ki Tae
authors.initials: KT
authors.lastname: Kim
authors.forename: Dae Hoon
authors.initials: DH
authors.lastname: Jeong
authors.forename: Young Nam
authors.initials: YN
authors.lastname: Kim
authors.forename: Bong Chul
authors.initials: BC
authors.lastname: Chung
authors.forename: Man Ho
authors.initials: MH
authors.lastname: Choi
mesh_terms: D000328:Adult; D001669:Biochemical Phenomena; D004967:Estrogens / Q000097:blood* / Q000737:chemistry / Q000302:isolation & purification; D005019:Ethyl Ethers / Q000737:chemistry; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006358:Hot Temperature; D006801:Humans; D016018:Least-Squares Analysis; D057230:Limit of Detection; D011225:Pre-Eclampsia / Q000097:blood; D011247:Pregnancy; D015203:Reproducibility of Results
chemical_list: D004967:Estrogens; D005019:Ethyl Ethers