To ensure high-quality metabolomics results, the method and instrument system must be qualified as being fit for purpose. This involves testing for losses or errors in the analytical workflow. To aid such performance assessments in MS metabolomics and simultaneously enable metabolite quantification, Eurisotop and CIL are pleased to offer the QReSS (Quantification, Retention, and System Suitability) kit. This is well suited for such applications, as demonstrated through collaborative work with Sciex, due to the carefully selected compounds and their inherent characteristics (e.g., molecular weight), as well as their experimental tendencies (e.g., broad elution behavior, absent from solubility issues or stability concerns). Please refer to the Metabolomics QReSS Kit flyer for mix composition details and an overview of the validation/applications.