The Quality Control (QC) Reference Material portfolio is a unique collection of standards and mixtures. These products allow the user to evaluate and benchmark their LC and LC-MS chromatography system before analysis of critical analytes. The products in the portfolio are all specially formulated based on the expertise of Waters scientist. Waters recommends to benchmark a chromatographic system with a QC Reference Material prior to system usage when there is confidence that the system is in good working order. It is recommended to run and save the initial results and to continue to compare the QC Reference Material results to the previous benchmark before any critical assay is run, and after any hardware, column or mobile-phase changes.