Simple Correction of Chemical Shift Changes in Quantitation

Andrii Lazariev¹, Florence Fauvelle², Martial Piotto^3,4, Karim Elbayed⁴, Jacques Namer⁵, Dirk van Ormondt⁶, Danielle Graveron-Demilly¹

High-resolution magic angle spinning (HRMAS) 1H spectroscopy is playing an increasingly important role for diagnosis. This technique enables setting up metabolite profiles of ex vivo pathological and healthy tissue. Automatic quantitation of HRMAS signals will provide reliable reference profiles to monitor diseases and pharmaceutical follow-up. Nevertheless, for several metabolites chemical shifts often slightly differ according to the microenvironment in the tissue or cells, in particular with its pH. This hampers accurate estimation of the metabolite concentrations mainly when using quantitation algorithms based on a metabolite basis-set. In this work, a very simple method to circumvent this problem is proposed.