Repositori URV

Identifier: TDX:765

Handle: https://hdl.handle.net/20.500.11797/TDX765

Authors:
Maroto Sánchez, Maria Alicia

Abstract:
According to the ISO Norm 17025, the accredited analytical laboratories should obtaintheir results accompanied by two basic quality parameters: traceability and uncertainty.Therefore, nowadays the analysts are increasingly urged to assess the traceability of theirresults and to estimate the uncertainty of these results. In this thesis, we have proposeddifferent methodologies to calculate uncertainty in analytical methods that are usedroutinely in the laboratory. These methodologies calculate uncertainty as a whole (i.e. bygrouping terms of uncertainty whenever possible) and use the information generated duringthe validation process and, specially, the information obtained in the assessment oftraceability. Moreover, the uncertainty can also be calculated using the informationgenerated during precision studies, during robustness studies and during the internal qualitycontrol.The advantage of the proposed methodologies is that they require few additional work tocalculate uncertainty because the analytical methods should always be validated beforeapplying them to the analysis of routine samples. We have developed the calculation ofuncertainty at one concentration level when traceability is assessed with several types ofreferences such as certified reference materials (CRM), reference methods andinterlaboratory studies. This uncertainty is calculated using the information obtained in theassessment of traceability. Moreover, this uncertainty can be calculated by using theinformation generated from control charts, precision studies and robustness studies. Thecalculation of uncertainty at one concentration level should only be applied in a restrictedconcentration range because it is assumed that both the method bias and precision are thesame in the whole concentration range. Ho