Pooled Calibrations and Retainment of Outliers Improved Chemical Analysis

Analytical chemistry has a large responsibility in society, and credibility and reliability are important concepts associated with chemical ana lysis. Metrology and Quality Assurance (QA) are key areas of interest in contemp orary research. Quality in measurements is illustrated by a series of experimen ts with several analytical technologies comprisi ng of ICP-MS, GC-MS and AAS. Th e scientific methodology relies on the concept of reproducibility that depen ds on type of analyte and type of apparatus. By applying the principle of poo led calibrations it is shown that the performance of the apparatus in terms of leve ls of uncertainty can be tested in a single laboratory. The uncertainties are com pared to predictions of the Horwitz formu la. It is suggested that this m ethod is universally applicable not only to the actual technologies but also to other technologies in other fields of science. The results indicate t hat the procedures outlined in the Eurachem/CITAC Guide are of tremendous value to analytical sciences because they direct researcher’s attention towards the concept of consensus values rather than tow ards true values. Introduction of certified reference materials (CRM’s) in metrology has provided much new information on working habits in professiona l laboratories and CRM’s may be applied to establish the true level of uncertainty for a given type of ana lytical method. Finally, it is proposed to devise a new procedure of method val idation that facilitates QA in general, thus saving many resources at labora tories.