title: Differential estimation of isomeric 2- and 4-methoxylated estrogens in serum by matrix-assisted laser desorption ionization-tandem mass spectrometry.
abstract: As a simple and rapid method for small-molecule analysis, matrix-assisted laser desorption ionization coupled with linear ion-trap tandem mass spectrometry (MALDI-LTQ-MS/MS) was used to differentially quantify 2- and 4-methoxyestrogens in spiked serum samples. Both 2- and 4-methoxyestrogens were consistently identified using distinct analyte-matrix adduct [M+H+CHCA](+) precursor ions when a mixture of 10 mg mL(-1) α-cyano-4-hydroxycinnamic acid (CHCA) in 0.2% trifluoroacetic acid/70% acetonitrile was used as the MALDI matrix. Especially, unusual isomeric product ions from each precursor ion were characterized during MALDI-MS/MS analysis, which permitted differential estimations of isomeric 2- and 4-methoxylated estrone and 17β-estradiol. The calibration linearity was higher than 0.99 in the dynamic range, while the inter-day precision and accuracy ranged from 6.8 to 30.6%, and from 91.4 to 108.5%, respectively. The present technique could be used as a screening assay for 2- and 4-methoxyestrogens without the need for prior chromatographic separation, opening up possible applications in large-scale pharmacokinetic studies.
authors.affiliation: Future Convergence Research Division, Korea Institute of Science and Technology, Seoul, Korea.
authors.forename: Ju-Yeon
authors.initials: JY
authors.lastname: Moon
authors.forename: Sun Ju
authors.initials: SJ
authors.lastname: Kim
authors.forename: Myeong Hee
authors.initials: MH
authors.lastname: Moon
authors.forename: Bong Chul
authors.initials: BC
authors.lastname: Chung
authors.forename: Man Ho
authors.initials: MH
authors.lastname: Choi
mesh_terms: D001774:Blood Chemical Analysis / Q000379:methods*; D003373:Coumaric Acids / Q000737:chemistry; D004967:Estrogens / Q000097:blood* / Q000737:chemistry*; D006801:Humans; D007536:Isomerism; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D003373:Coumaric Acids; D004967:Estrogens; C007175:alpha-cyano-4-hydroxycinnamate