title: Determining estrogens using surface-assisted laser desorption/ionization mass spectrometry with silver nanoparticles as the matrix.
abstract: We describe the application of silver nanoparticles (Ag NPs) as matrices for the determination of three estrogens using surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS). Because Ag NPs have extremely high absorption coefficients (1.2 x 10(8) M(-1) cm(-1)) at 337 nm, they are effective SALDI matrices when using a nitrogen laser. Three tested estrogens--estrone (E1), estradiol (E2), and estriol (E3)--adsorb weakly onto the surfaces of the Ag NPs, through van der Waals forces. After centrifugation, the concentrated analytes adsorbed on the Ag NPs were subjected directly to SALDI-MS analyses, with the limits of detection for E1, E2, and E3 being 2.23, 0.23, and 2.11 microM, respectively. The shot-to-shot and batch-to-batch variations for the three analytes were less than 9% and 13%, respectively. We validated the practicality of this present approach through the quantitation of E2 in human urine. Using this approach, we determined the concentration of E2 in a sample of a pregnant woman's urine to be 0.16+/-0.05 microM (n=10).
authors.affiliation: Department of Nature Science and Education, National Taitung University, Taitung, Taiwan.
authors.forename: Tai-Chia
authors.initials: TC
authors.lastname: Chiu
authors.forename: Lin-Chau
authors.initials: LC
authors.lastname: Chang
authors.forename: Cheng-Kang
authors.initials: CK
authors.lastname: Chiang
authors.forename: Huan-Tsung
authors.initials: HT
authors.lastname: Chang
mesh_terms: D000328:Adult; D004958:Estradiol / Q000737:chemistry / Q000652:urine; D004964:Estriol / Q000737:chemistry / Q000652:urine; D004967:Estrogens / Q000032:analysis* / Q000652:urine; D004970:Estrone / Q000737:chemistry / Q000652:urine; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D053768:Metal Nanoparticles / Q000737:chemistry*; D011247:Pregnancy; D015203:Reproducibility of Results; D012834:Silver / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000295:instrumentation / Q000379:methods*
chemical_list: D004967:Estrogens; D004970:Estrone; D012834:Silver; D004958:Estradiol; D004964:Estriol