“Uncertainty in qualitative and quantitative analysis“
29 e 30 maggio 2017
A. G. Leventis House
Campus of the University of Cyprus
Nowadays, almost all human activities depend, directly or indirectly, of quantifications or qualifications performed in chemistry involving the determination of a scalar or a nominal chemical property respectively. Quantifications are performed by measurements and qualifications by examinations of nominal properties.
The measurements can only fulfil their intended purpose adequately if they are traceable to suitable references and associated with a small enough uncertainty. Measurement traceability is obtained by utilising references for the measurements or for all relevant analytical operations. For example the correction of measurement results for recovery, by that observed in the analysis of a reference material, can be used to guarantee measurements traceability to the reference value. However, this correction is only meaningful if the reference values are traceable to an adequate reference and if the measurements of recovery on the reference materials is representative of the recovery on the measurement of the sample.
The measurements uncertainty should be smaller than a target measurement uncertainty that defines the maximum admissible uncertainty. The magnitude of measurement uncertainty is particularly relevant in compliance assessment to ensure that the risks of false compliance decision is under control.
Measurement procedure validation aims at collecting evidence of the measurements fitness for the intended use, focused on measurement scope and uncertainty. After measurement procedure validation, subsequent measurements quality should be monitored through an adequate quality control that checks performance parameters assessed in the validation.
The quality of nominal properties examinations also depends on the traceability and uncertainty of the test results. The qualitative analysis reference should be adequate for the identification and the reported nominal property uncertainty should be sufficiently small. Although, traceability and uncertainty of qualitative analysis results, are concepts not as widely disseminated as for measurements, these are taken care of, but using different terminology and techniques. For example, the identification of trace levels of compounds in complex matrices by GC-MS can rely on a MS library produced in equipment with different performance characteristics from the one being used with an impact on the probability of reported identification being correct, i.e. on nominal examination uncertainty.
Nominal examination procedures must also be adequately validated and subsequent tests quality monitored by an adequately designed test quality control.
This workshop will discuss all relevant concepts and their respective implementation to guarantee that measurements and examinations of nominal properties are fit for their intended purpose. It will also discuss how these concepts are implemented in accredited laboratories, taking into account the current ILAC policies and any other relevant documents from Regional Cooperation Bodies such as the European Cooperation for accreditation.
In allegato il programma dettagliato.