Browsing by Author "Pankko, Emmi-Kaisa"

The literature review deals with the principles of Total Diet Studies (TDS) and the implementations of the method in scientific literature. In addition the TDS Exposure project and the role of the Finnish Food Safety Authority Evira in that was introduced. Also the challenges set by TDS for trace element analytics was discussed. In the literature review the chemical and nutritional properties and quantities in foods of manganese, copper, zinc, selenium and cadmium were introduced. Mn, Cu and Se were included in the TDS Exposure project in Evira and Zn and Cd were interesting elements in the routine analysis in the Chemistry and Toxicology Research Unit. The aim of the research was to reassure the reliability of the ICP-MS-method by revalidating the method and to examine the possibility for lowering the LODs and LOQs in the perspective of TDS. In this thesis the quantities of Mn, Cu, Zn, Se and Cd in milk, meat and vegetable samples were analysed with validated inductively coupled plasma - mass spectrometry (ICP-MS). Based on the analytical results values for trueness, repeatability, reproducibility, limits of detection (LOD), limits of quantification (LOQ) and measurement uncertainties were calculated for each element and matrix. The measurement uncertainties were calculated with the MUKit-software which is uncertainty calculation software targeted for analytical laboratories. The trueness values for the examined elements were 86–115 %. The repeatability and reproducibility values were 2–10 % and 1–11%, respectively. Based on the revalidation the LODs and LOQs of Mn and Cd could be lowered and for Cu, Zn and Se the LODs and LOQs could be retained. The measurement uncertainties for Mn, Cu, Zn, Se and Cd were 18–22 %, 32–46 %, 11–32 %, 29–35 % and 19–58 %, respectively. The uncertainties of Mn, Cu and Se could be used in reporting of the results. The uncertainties for Zn and Cd should be recalculated taking into account the realistic quantities of these elements in foods. Also more concurrent samples should be included. With the updated validation parameters and LOQs more compatible risk assessment can be performed based on the routine measurements of the laboratory. The results can also be used for a potential TDS project in the future.