The use of reference materials: A tutorial

Any review of the analytical literature shows that, while reference materia ls are routinely used in laboratories world-wide, not all uses follow ISO G uide 33 (1989), which outlines best practices. Analytical data quality can suffer as a result. This paper reviews the various uses that the geoanalyti cal community has made of reference materials from a historical perspective , and suggests improvements in practice that would more closely follow ISO Guide 33 recommendations.