A Method for Quantification of Tetrahydroglucocorticoid Glucuronides in Human Urine by LC/MS/MS with Isotope-coded Derivatization

Abstract

The determination of urinary tetrahydroglucocorticoid (THGC) glucuronides might prove helpful in the diagnosis, pathophysiological analysis and assessment of the therapeutic efficacy of the diseases caused by abnormal cortisol secretion. We developed and validated a method for the determination of the THGC glucuronides in human urine using liquid chromatography/electrospray ionization (ESI)–tandem mass spectrometry not requiring enzymatic hydrolysis. The method employed a derivatization using an ESI-enhancing reagent for carboxylic acids, 1-[(4-dimethylaminophenyl)carbonyl]piperazine (DAPPZ), and its isotopologue, ²H₄-DAPPZ. The deproteinized urine samples were derivatized with DAPPZ. The ²H₄-DAPPZ-derivatized standards of known amounts were then added to the DAPPZ-derivatized urine samples and served as the internal standards. The DAPPZ-derivatization enhanced the assay sensitivity and reduced the sample volume, and the use of ²H₄-DAPPZ significantly improved the assay accuracy. The developed method enabled the separate quantification and profiling of the urinary THGC glucuronides and had a satisfactory application for the real sample analysis.