Background: Stimulation with intravenous adrenocorticotropic hormone (ACTH) is a widely used diagnostic procedure to characterize the adrenocortical function. Currently, the response of serum cortisol, mainly quantified by immunoassays, is the only established read-out of this test. By using liquid chromatography coupled with mass spectrometry (LC-MS/MS) simultaneous determination of several steroids that respond to ACTH stimulation is now possible.
View Article and Find Full Text PDFJ Chromatogr B Analyt Technol Biomed Life Sci
June 2016
We used ferromagnetic particles as a novel technique to deproteinize plasma samples prior to quantitative UHPLC-MS/MS analysis of seven eicosanoids [thromboxane B2 (TXB2), prostaglandin E2 (PGE2), PGD2, 5-hydroxyeicosatetraenoic acid (5-HETE), 11-HETE, 12-HETE, arachidonic acid (AA)]. A combination of ferromagnetic particle enhanced deproteination and subsequent on-line solid phase extraction (on-line SPE) realized quick and convenient semi-automated sample preparation-in contrast to widely used manual SPE techniques which are rather laborious and therefore impede the investigation of AA metabolism in larger patient cohorts. Method evaluation was performed according to a protocol based on the EMA guideline for bioanalytical method validation, modified for endogenous compounds.
View Article and Find Full Text PDFFor quotable quantitative analysis of endogenous analytes in complex biological samples by isotope dilution LC-MS/MS, the creation of appropriate calibrators is a challenge, since analyte-free authentic material is in general not available. Thus, surrogate matrices are often used to prepare calibrators and controls. However, currently employed validation protocols do not include specific experiments to verify the suitability of a surrogate matrix calibration for quantification of authentic matrix samples.
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