Reasons for validating evaluation instruments
Representatives of the pharmaceutical and chemical industry have published papers on the validation of analytical methods.
Hokanson (9,10) applied the life cycle approach, developed for computerized systems, to the validation and revalidation of methods.
The AOAC (15) has developed a Peer-Verified Methods validation program with detailed guidelines on exactly which parameters should be validated.
Winslow and Meyer (16) recommend the definition and application of a master plan for validating analytical methods. Breaux and colleagues have published a study on analytical methods development and validation (17).
It is not always necessary to validate all analytical parameters that are available for a specific technique.
For example, if the method is to be used for qualitative trace level analysis, there is no need to test and validate the method’s limit of quantitation, or the linearity, over the full dynamic range of the equipment.
Green (11) gave a practical guide for analytical method validation, with a description of a set of minimum requirements for a method.
Renger and his colleagues (12) described the validation of a specific analytical procedure for the analysis of theophylline in a tablet using high-performance thin layer chromatography (HPTLC).
It meets criteria such as ease of use; ability to be automated and to be controlled by computer systems; costs per analysis; sample throughput; turnaround time; and environmental, health and safety requirements.
This ensures that one set of consumables can be used for most experiments and avoids unpleasant surprises during method validation.
Operators should be sufficiently familiar with the technique and equipment.
It also describes what is important when transferring a method.
The validity of a specific method should be demonstrated in laboratory experiments using samples or standards that are similar to unknown samples analyzed routinely.