title: Unique potentiometric detection systems for HPLC determination of some steroids in human urine.
abstract: Isocratic HPLC with potentiometric detection is used for the determination of some 17-ketosteroids (17-KS), e.g., androsterone, dehydroepiandrosterone and estrone, and their respective sulfated conjugates (17-KSS). Glassy carbon or composite electrodes containing a mixture of graphite and poly(vinyl chloride), PVC, were used as substrate electrodes. These substrates were covered either by montmorillonite or potassium tetrakis(p-chlorophenyl) borate containing PVC-based rubber phase membranes. The neutral 17-KS compounds were derivatized with Girard's reagent P (GP) to obtain cationic pyridinium acetohydrazones prior to the HPLC/potentiometric detection assay. No side reactions were observed, and the GP itself was not interfering. The method yielded accurate and reproducible results and was applicable to samples containing down to micromolar concentrations. Next, the 17-KSS compounds, acting as anionic charged molecules, were determined directly in human urine samples with the HPLC/potentiometry combination without preliminary derivatization. For this purpose, a new anion-sensitive potentiometric electrode was developed using a macrocyclic polyamine containing, PVC-based, rubber phase membrane. The three 17-KSS compounds were also determined accurately down to micromolar concentrations. Especially, the main androgen metabolites as dehydroepiandrosterone sulfate and androsterone sulfate could be selectively determined with a developed potentiometric sensor in human urine samples without time-consuming cleanup and preconcentration step.
authors.affiliation: Departement Chemie, Faculteit Wetenschappen, Universiteit Antwerpen, Antwerpen, Belgium.
authors.forename: Bert
authors.initials: B
authors.lastname: Vissers
authors.forename: Joseph
authors.initials: J
authors.lastname: Everaert
authors.forename: Justyna
authors.initials: J
authors.lastname: Sekula
authors.forename: Anna
authors.initials: A
authors.lastname: Malak
authors.forename: Hugo
authors.initials: H
authors.lastname: Bohets
authors.forename: Grzegorz
authors.initials: G
authors.lastname: Bazylak
authors.forename: Luc J
authors.initials: LJ
authors.lastname: Nagels
mesh_terms: D015068:17-Ketosteroids / Q000737:chemistry* / Q000652:urine*; D001622:Betaine / Q000031:analogs & derivatives; D002138:Calibration; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004566:Electrodes; D006801:Humans; D015394:Molecular Structure; D010865:Pilot Projects; D011199:Potentiometry / Q000379:methods*; D013455:Sulfur / Q000737:chemistry
chemical_list: D015068:17-Ketosteroids; D001622:Betaine; D013455:Sulfur; C012332:Girard's reagent T