title: Automated solid-phase extraction for concentration and clean-up of female steroid hormones prior to liquid chromatography-electrospray ionization-tandem mass spectrometry: an approach to lipidomics.
abstract: A method for determination of free and glucuronide-conjugated female steroid hormones in urine at the pgmL(-1) level is here presented. For this purpose, a dual approach with or without beta-glucuronidase hydrolysis has been developed to succeed in this analysis. The target analytes were two progestogens - progesterone and pregnenolone - and three endogenous estrogens - estradiol, estriol and estrone. Separation and detection were carried out by liquid chromatography electrospray ionization and tandem mass spectrometry (LC-ESI-MS-MS) with a triple quadrupole (qQq) mass detector. The determination step was optimized by multiple reaction monitoring for highly selective identification and sensitive quantification of female hormones in a complex sample such as human urine. As these compounds are present in urine at very low concentration (ngmL(-1) level), a preconcentration and clean-up step by solid-phase extraction was automatically carried out prior to the chromatographic step in order to improve the sensitivity of the method. This sample pretreatment was performed using a lab-on-valve (LOV) manifold which provided preconcentration factors ranging from 59.1 to 72.3 for 10mL urine. The detection and quantification limits were in the ranges 1.8-18pg and 6-61pg on-column, respectively, with precision values from 1.93 to 10.99%, expressed as relative standard deviation. These results enable to conclude the suitability of the LOV-LC-qQq approach for determination of the lipidomic profiling of the main female steroid hormones in a difficult matrix as human urine. The method can be potentially applied to the clinical and other metabolomic areas.
authors.affiliation: Department of Analytical Chemistry, Annex Marie Curie Building, Campus de Rabanales, University of Córdoba, Córdoba, Spain.
authors.forename: B
authors.initials: B
authors.lastname: Alvarez Sánchez
authors.forename: F Priego
authors.initials: FP
authors.lastname: Capote
authors.forename: J Ruiz
authors.initials: JR
authors.lastname: Jiménez
authors.forename: M D
authors.initials: MD
authors.lastname: Luque de Castro
mesh_terms: D000328:Adult; D001331:Automation; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D005260:Female; D012739:Gonadal Steroid Hormones / Q000032:analysis* / Q000737:chemistry / Q000652:urine; D006801:Humans; D052616:Solid Phase Extraction / Q000379:methods*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D012739:Gonadal Steroid Hormones