Development of a reference material for copper and iron in wine

Reference materials are essential tools to achieve comparability and traceability between measurements. However, reference materials in food matrices are scarce. In this article, the development of a reference material for copper and iron in wine is described. To assign the reference values, methods for measurement of copper and iron in wine by flame atomic absorption (FAA) were previously validated. Special attention was paid to sample treatment, since the wine matrix could affect the accuracy of measurements. For copper, the sample treatment was microwave digestion, while simple dilution of sample was enough to avoid matrix effects in iron measurements. The assigned reference values±expanded uncertainties were 2.986±0.102 mg/L for iron and 0.154±0.004 mg/L for copper.