ABSTRACT
This chapter attempts to some of the confidence issues particular to the trace analysis of metals. Good quality assurance practice requires that each new lot of each elemental standard solution be qualified by measuring it against an appropriate metal alloy reference material. Many metal alloy certified reference materials do include uncertainty values on the accompanying certificate. The use of reference materials in trace analysis is a very large subject that touches in some way or another nearly every form that the analytical process can take. The fact that analytical calibration methods vary widely in their requirements for reference materials—both in number and how closely they must match the sample matrix. There is an interesting inverse relationship between the calibration class of a method and its validation requirements. Verification is the process of determining that a method is doing what it did when it was last calibrated and validated.
