Objective: The aim of this study was to prepare and certify a new Certified Reference Material
(CRM) of quercetin for the quality control of quercetin and related functional foods and botanical supplements.
Methods: Three different methods, including coloumetric titration (CT), differential scanning calorimetry
(DSC) and mass balance (MB) methods were used in the purity determining process.
Results: The purity results determined by the three methods were consistent, and the CT has the highest
accuracy and the smallest uncertainty.
Conclusion: CT and DSC methods were established for purity determination of quercetin for the first
time. The purity of quercetin CRM, after validation and evaluation, was 99.3% ± 0.4% (k = 2, P = 0.95).
The new CRM can be widely used to quantitatively analyse quercetin and other related functional foods and