Multi-elemental composition of Slovenian milk: analytical approach and geographical origin determination

Abstract

The main objective in multi-elemental analysis in food is to obtain the best results in the shortest time and with minimal contamination and reagent consumption. Three different methods were investigated in the present study to obtain the elemental content in milk samples: energy dispersive X-ray fluorescence spectrometry (EDXRF), k₀-instrumental nuclear activation analysis (k₀-INAA) and the inductively coupled plasma mass spectrometry (ICP-MS). Quality assurance including intercomparison exercises of these measurements proved entirely satisfactory and was typical of that previously established for this technique. It was found that EDXRF was the cheapest, simplest and environmental friendly method for analysis of multi-elemental composition (P, S, Cl, K, Ca, Zn, Br, Rb, Sr) in milk samples, while for determination of Mn, Fe, Cu, Se content and possible identification of pollutants such as As, Cd and Pb ICP-MS was a method of choice due to its excellent sensitivity and accuracy. These two methods were also used to determine the multi-elemental composition in Slovenian raw cow milk from different geographical regions: Alpine, Mediterranean. Dinaric and Panoninan in December 2013. Linear discriminant analysis (LDA) was used to explore multi-elemental analysis of milk samples to obtain classification according to geographical regions. Regional discrimination was most successful taking into account Ca, S, P, K, and Cl with prediction ability of 66.7%.