A rapid and sensitive HPLC-MS/MS method for determination of endogenous creatine biosynthesis precursors in plasma of children with viral myocarditis.

A simple, rapid and sensitive HPLC-MS/MS method for simultaneous determination of 4 of amino acids, guanidinoacetic acid, S-adenosylmethionine and S-adenosylhomocysteine in human plasma was developed and validated. The method requires no tedious sample preparation, derivatization reagents or ion-pairing reagents. Samples were prepared by combining plasma with a chilled mixture of acetonitrile (ACN) and water, followed by centrifugation and diluting the supernatant with 2 volumes of water. Analytes were detected with multiple reaction monitoring using a positive scan mode with electrospray ionization (ESI). In the assay, all the analytes showed good linearity over the investigated concentration range (r > 0.99). The accuracy expressed in relative error (RE) was between -5.0% and 13.2%, and the precision expressed in coefficient of variation (CV) ranged from 0.6% to 14.7%. In the two spiked levels (low and high), the averaged recoveries of analytes were between 45.0% and 110.9% and the recovery of internal standard was 92.0%. This method was successfully applied to studying the concentration changes of endogenous creatine (Cr) synthesis precursors in the plasma of children with viral myocarditis after intravenous administration of phosphocreatine (PCr).
(Copyright © 2019. Published by Elsevier B.V.)