Describing and writing analytical methods

Why is it that many published methods of analysis do not work when they are applied outside the developer s laboratory Why do so many collaborative trials fail to produce consistent results Some of the reasons may lie with inadequacy of method validation, sample preparation or lack of specification of key analytical parameters. However, even for well developed procedures, the failure 

The purpose of a written analytical procedure must be to convey the instructions necessary to allow a competent analytical chemist to reproduce the procedures and measurement processes faithfully, to apply the method to their sample and to state the results with appropriate confidence. I stress the word competent. Method transfer can only be accomplished between appropriately trained and qualified personnel. There is an unfortunate belief, in some quarters, that if procedures are written in an all-embracing and exhaustively detailed manner then professionally trained and qualified staff are not always necessary. This is a dangerous and misguided belief. 

Anyone involved in writing analytical procedures and methods for the first time generally underestimates the difficulty of the task until faced with the results of an unsuccessful transfer process. Why is it then that we have a dearth of guidelines for such a task The major texts on analytical chemistry and analytical science do not contain such advice. Even recent books on the validation of analytical methods, The Approved Text to the FECS Curriculum of Analytical Chemistry and Quality Assurance in Analytical Chemistry, excellent though they are in other areas, make cursory reference, if any, to the requirements for good detailed written procedures. 

The Analytical Methods Committee s own compilation of official and standardised methods of analysis is widely used and respected within the analytical community. The importance of standardised formats for method documentation has been emphasised by the AMC s guidelines for achieving quality in trace analysis. They list 17 headings for inclusion in the documentation  

Taking both these approaches into consideration. Table 13 gives a simplified framework within which to define an analytical procedure. 

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