title: The importance of chromatographic resolution when analyzing steroid biomarkers.
abstract: The analyses of endogenous substances as biomarkers presents challenges that are distinctly different from the analyses of drugs or other xenobiotic substances. This is particularly true for estrogens. When no matrix is available which does not contain some level of the biomarker of interest, specificity cannot be demonstrated. Therefore it cannot be known whether the analyte signal includes a response from another substance. This uncertainty is increased by the fact that biomarkers are often created as part of a complex biosynthetic process that also creates a large number of substances with very similar structures and sometimes the same mass. Because of this, the two most powerful selectivity tools in the analysis of drugs, mass selective detection and MS/MS, are often rendered ineffective. The only remaining selectivity tool is chromatography and as will be demonstrated these separations can be very challenging. Failure to achieve specificity is perhaps the leading cause for inaccuracy of biomarker data and inter-laboratory variability.
authors.affiliation: inVentivHealth, 301 College Rd E, Princeton, NJ 08540, United States. Electronic address: james.settlage@inventivhealth.com.
authors.forename: James
authors.initials: J
authors.lastname: Settlage
authors.affiliation: inVentivHealth, 301 College Rd E, Princeton, NJ 08540, United States.
authors.forename: Thomas
authors.initials: T
authors.lastname: Oglesby
authors.affiliation: inVentivHealth, 301 College Rd E, Princeton, NJ 08540, United States.
authors.forename: Agnita
authors.initials: A
authors.lastname: Rajasekaran
authors.affiliation: Mass Spectrometry Operations, Princeton Lab, inVentivHealth, 301 College Rd E, Princeton, NJ 08540, United States.
authors.forename: Clark
authors.initials: C
authors.lastname: Williard
authors.affiliation: Bioanalytical Services, inVentivHealth, 301 College Rd E, Princeton, NJ 08540, United States.
authors.forename: George
authors.initials: G
authors.lastname: Scott
mesh_terms: D015415:Biomarkers / Q000032:analysis* / Q000097:blood; D002849:Chromatography, Gas / Q000379:methods*; D004967:Estrogens / Q000032:analysis; D006801:Humans; D013058:Mass Spectrometry / Q000379:methods*; D013256:Steroids / Q000032:analysis* / Q000097:blood; D053719:Tandem Mass Spectrometry / Q000379:methods; D013739:Testosterone / Q000097:blood
chemical_list: D015415:Biomarkers; D004967:Estrogens; D013256:Steroids; D013739:Testosterone
keywords: Accurate quantification; Estrogen metabolites; High resolution chromatography; Specificity