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Published on: September 27, 2024
Determination of methionine-enkephalin and leucine-enkephalin by LC-MS in human plasma: Study of pre-analytical
Aliye Ozalp1, Begona Barroso1, John Meijer1
1Astellas Pharma Europe, Sylviusweg 62, 2333 BE Leiden, The Netherlands.
Abstract:
The aim of this work was to assess the influence of preanalytical variables on the stability of two endogenous opioid peptides (Methionine-Enkephalin and Leucine-Enkephalin) in human plasma. For this purpose, first a sensitive LC-MS/MS analytical method was developed and validated for the simultaneous quantitative analysis of these two peptides. The methodology consisted of a simple protein precipitation step followed by UPLC separation and MRM quantitative analysis using a stable isotope labelled Methionine-Enkephalin as internal standard. The method with a limit of quantitation of 10 pg/mL showed good reproducibility with excellent accuracy and precision, and was linear up to 2000 pg/mL. An extensive evaluation of the pre-analytical stability of these peptides in human blood was carried out to ensure an adequate sample collection procedure to obtain reliable results in the analysis of clinical samples.
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