An isotope-dilution LC-MS/MS method for the simultaneous quantification of meropenem and its open-ring metabolite in serum

2021 ◽  
Vol 197 ◽  
pp. 113944
Author(s):  
Sophie Rakete ◽  
Carina Schuster ◽  
Michael Paal ◽  
Michael Vogeser
Keyword(s):  
Isotope Dilution ◽  
Simultaneous Quantification ◽  
Open Ring

Simultaneous quantification of endogenous and exogenous plasma glucose by isotope dilution LC-MS/MS with indirect MRM of the derivative tag

2018 ◽  
Vol 410 (7) ◽  
pp. 2011-2018 ◽  
Author(s):  
Lingling Yu ◽  
Chao Wen ◽  
Xing Li ◽  
Shiqi Fang ◽  
Lichuan Yang ◽  
...  
Keyword(s):  
Isotope Dilution ◽  
Plasma Glucose ◽  
Simultaneous Quantification

Application of stable isotopes and AF4/ICP-SFMS for simultaneous tracing and quantification of iron oxide nanoparticles in a sediment–slurry matrix

2016 ◽  
Vol 31 (4) ◽  
pp. 890-901 ◽  
Author(s):  
Björn Meermann ◽  
Kristina Wichmann ◽  
Franziska Lauer ◽  
Frank Vanhaecke ◽  
Thomas A. Ternes
Keyword(s):  
Stable Isotopes ◽  
Iron Oxide ◽  
Isotope Dilution ◽  
Analytical Approach ◽  
Isotope Labeling ◽  
Oxide Nanoparticles ◽  
Simultaneous Quantification ◽  
Sediment Slurry ◽  
Natural Iron ◽  
On Line

A new analytical approach was developed by us allowing for unambiguous tracing and simultaneous quantification of Fe-oxide ENPs in the presence of a natural iron colloid matrix. The approach relies on isotope labeling of ENPs and reverse post-channel species-unspecific on-line isotope dilution in combination with AF4/ICP-SFMS.

Quantification of Isotope-Labeled and Unlabeled Folates and Folate Catabolites in Urine Samples by Stable Isotope Dilution Assay

2013 ◽  
Vol 83 (2) ◽  
pp. 112-121 ◽  
Author(s):  
Barbara E. Büttner ◽  
Veronica E. Öhrvik ◽  
Peter Köhler ◽  
Cornelia M. Witthöft ◽  
Michael Rychlik
Keyword(s):  
Stable Isotope ◽  
Isotope Dilution ◽  
Limit Of Detection ◽  
Test Dose ◽  
Clinical Samples ◽  
Assay Sensitivity ◽  
Stable Isotope Dilution ◽  
Simultaneous Quantification ◽  
Stable Isotope Dilution Assays ◽  
Dual Label

Dual-label stable isotope dilution assays for the simultaneous quantification of isotopologic folates in clinical samples offer the perspective for differentiating between unlabeled folates from endogenous body pools and administered [13C5]-labeled folates from a test dose when performing bioavailability trials. In contrast to intact folates, this methodology could hitherto not be applied to the quantification of the folate catabolites, p-aminobenzoyl glutamate and p-acetamidobenzoyl glutamate. In this study, [2H4]-p-aminobenzoyl glutamate, [2H4]-p-acetamidobenzoyl glutamate, and unlabeled p-acetamidobenzoyl glutamate were synthesized. The synthesis of the [2H4]-labeled compounds started at unlabeled p-aminobenzoic acid. For the formation of p-acetamidobenzoyl glutamate, p-aminobenzoyl glutamate was acetylated. The new substances were applied successfully in stable isotope dilution assays for the simultaneous quantification of the [13C5]-labeled and unlabeled folate catabolites, p-aminobenzoyl glutamate and p-acetamidobenzoyl glutamate, along with the predominant folate vitamers in urine. The assays were based on clean-up by strong anion exchange followed by liquid chromatography-tandem mass spectrometry detection. Assay sensitivity was sufficient to detect the folate catabolites in physiologic concentrations. The limit of detection was below 0.4 and 0.3 nmol/100 g for p-aminobenzoyl glutamate isotopologues and p-acetamidobenzoyl glutamate isotopologues in urine, respectively. The successful synthesis of [2H4]-p-aminobenzoyl glutamate, [2H4]-p-acetamidobenzoyl glutamate, and unlabeled p-acetamidobenzoyl glutamate and the implementation of these substances in stable isotope dilution assays allows dual-label designs that provide a more detailed insight into human folate metabolism.

scholarly journals Simultaneous Quantification of Steroids in Rat Intratesticular Fluid by HPLC-Isotope Dilution Tandem Mass Spectrometry

2011 ◽  
Vol 33 (4) ◽  
pp. 691-698 ◽  
Author(s):  
A. Renne ◽  
L. Luo ◽  
J. Jarow ◽  
W. W. Wright ◽  
T. R. Brown ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Tandem Mass Spectrometry ◽  
Isotope Dilution ◽  
Tandem Mass ◽  
Simultaneous Quantification
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