Determination of the reference value of nitrogen mass fraction in the reference material of Polish soil

Ensuring a traceability and meaningful of a measurements is one of the most important stages of each analysis, each measurement. It is especially important for measurement of the environmental samples, like soil, which is a very complex matrix. A certified reference materials (CRMs) should be routinely used for this purpose. The paper discusses the procedure for preparation of the soil samples for certification as CRM. As for agricultural reasons there is a growing demand for CRMs regarding a nitrogen mass fraction in the Polish soil, we prepared such a material and established the reference value with associated measurement uncertainty. Homogeneity and stability of the material were shown to be appropriate for the intended purpose. The presented approach can also be used in a process of manufacture of a laboratory reference material, which can be used for a routine quality control.