Preparation and characterization of new reference material for inorganic analysis of pumpkin seed flour - An interlaboratory program.

This work describes preparing a certified reference material for pumpkin seed flour for use in inorganic analyses of vegetable foods. The elements studied were potassium, magnesium, phosphorus, zinc, copper, iron, manganese, and calcium. The ISO Guides were employed in the homogeneity and stability tests, interlaboratory program, and assignment of uncertainty value. The material was stable for 12 months at temperatures of -10 °C, 25 °C, and 45 °C, with minor uncertainties. Chemometric techniques, such as principal component analysis (PCA) and hierarchical clustering analysis (HCA), were employed in the homogeneity and stability studies. The confidence ellipse technique allowed a simple and rapid evaluation of the data furnished by the collaborating laboratories regarding the precision of the results. The findings showed that pumpkin seed flour could be considered a raw material for preparing reference material, considering its availability and characteristics of its matrix, including the presence of trace and essential elements.