1. Principles of method validation

1.1 Analysis method life cycle

All too often, analysis methods tend to be described as immutable, fixed procedures. This is the impression given by manuals and other technical standards. Yet, like any production process, analysis methods are born, evolve and die. To clearly understand the role and place of validation in the life of an analysis method, it is interesting to describe its life cycle, from the moment it is chosen to the moment it is abandoned.

Figure 1 summarizes the various stages in this cycle. First, the method is selected, i.e. from all the physico-chemical methods known or mastered by the laboratory, the one that will enable the determination of one or more...