One of the aspects of the stability of solutions of certified reference materials is the content of ions of transition metal – such as iron and manganese. Ions, which have access to the air, can catalyze for expamle red-ox reactions, causing changes in the composition of the solution and may change the concentration of standardized substance in the solution.
Other metal ions – those which are Lewis acids, e.g. zinc or lithium – can catalyze solvolysis reactions, modify the structure of the solubles, and thus – change the concentration in time.
To avoid such situations, we offer certified reference materials that have been checked for the presence of metals by ICP – MS/TOF method. The absence of inorganic impurities guarantees our customers long durability of certified reference material during storage.