Helmut Gnnzler

Validation in Chemical Measurement Helmut Gnnzler 2005 edition

Validationofmeasurementmethodshasbeenusedforavery ciated measurement uncertainty? The answer must be: no. longtimeinchemistry. Itismostlybasedontheexamination Therecanneverbeamechanismorrecipeforproducing - of a measurement procedure for its characteristics such as tomatically ?valid? results because one can never eliminate precision, accuracy, selectivity, sensitivity, repeatability, re- theskills,theroleandtheresponsibilityoftheanalyst. producibility,detectionlimit,quanti?cationlimitandmore. ISO 9000:2000, item 3. 8. 5 de?nes validation as ?con?r- When focussing on quality comparability and reliability mation by examination and provision of objective evidence in chemical measurement, the ?elds of interest to this Jour- that the requirements for an intended use are ful?lled?. The nal, one stumbles into various interpretations of the term revised edition of the VIM (?VIM3?), is likely to ?ne-tune validation. It is one more example of a term which is used thisde?nitionoftheconcept?validation?tobe?con?rmation sometimes very consistently, sometimes very loosely or in- through examination of a given item and provision of - deed ambiguously. Since the term is very common in the jective evidence that it ful?lls the requirements for a stated chemical community, it is important that its meaning be intendeduse?. nd clear. Turning to the 2 edition of the International Vo- Lookingatsimplepractice, manypeoplearelookingfor cabulary of Basic and General terms in Metrology (VIM) aformaldecisionthatagivenmeasurementmethod automat- (1993), surprisingly we do not ?nd a de?nition. Webster?s ically gives them ?valid? i. e. reliable results. One wonders Dictionary of the English language (1992) tells us that val- what this has to do with ?stated intended use?. Reliab- idation is ?making or being made valid?. Obviously valida- ity clearly is a property of a measurement result.