A standard minimum size for a sample delivered for an isotopic analysis of Sr and Nd is, at rock samples, at least 1 g of powder of analytical refinement, at samples of water for Sr analysis 100 ml. Samples of soluble carbonates can be of a piece, samples of teeth for a tooth enamel as well so. Minimal is the total quantity of Sr 2&mju;g and Nd 200ng in a sample. This is necessary to be regarded at samples with very low concentration, and in cases when limited quantity of material is available.
It is necessary to document concentration of Sr and Nd at samples, the type of material (rock classification, water type and alike), and a locality.
Regarding to a limited capacity it is necessary all commissions to consult beforehand with the laboratory staff.
Quality and usability of the laboratory result analysis of natural material generally depends on several parameters which are necessary to be regarded during sampling:
- Representativeness of a sample – the sample has to have the composition really representing the composition of a researched reservoir, what in a case of rock samples means e, g, its sufficient quantity regarding its grain size composition, absence of products of weathering and alike and sample dividing by quartering during the preparatory stage.
- Sample purity – in a number of cases is a concentration of a followed element very low; by contamination, therefore, can come to a substantial shift of an isotope ratio value. Problems can arise namely at such a situation when the contaminant has a contrast isotope composition or a high concentration of an element comparing to that of a sample. It also depends on a requirement on determination accuracy.
- Sample material (analytical matrix) – in special cases the analysis can be influenced or excluded by a difficult transfer of the sample to a solution; high concentration of same elements can bloc the separation or measuring of the sample. This is necessary to consult with the laboratory staff.