Determination of Trace Elements and Species in Foodstuffs

Multi-element trace analysis is an important prereqnisite for the qnality assurance of foodstuffs with respect to the characterization of non-essential, toxic and essential (nutrient) elements as pollutions or as mineral elements relevant to health. Contamination with heavy metals such as Cd, Pb or Hg has become a serious problem with increasing environmental (artificial) contamination e.g., due to industrial pollution. The increasing use of inorganic mass spectrometric techniques (especially of ICP-MS) in the analysis of foodsmffs for multi-element analysis of trace elements or the detection of selected elements and species at a low concentration level has resnlted from advances in very sensitive and quantitative measurements of metals, metalloids and several non-metals, including their speciation. 

Clough and co-workers reported on the uncertainty contribution using single and double isotopi-cally enriched spikes in the isotope dilution approach employing a multiple ion collector ICP-MS combined with an HPLC and with cold vapour generation (CV) to form HPLC-CV-MC-ICP-MS for the determination of MeHg in fish tissue. Two fish tissue reference materials DORM-2 (NRC, Canada) and BCR 464 were employed in these studies. The amount of each certified reference 

Specific recommendations on contaminants (e.g., maximum levels of lead, cadmium or mercury) in foodstuffs are summarized in the European Union Regulations. The specifications concerning trace elements in foods and food additives are As 3mgkg , Pb lOmgkg , and Hg and Cd lmgkg .  

Size exclusion chromatography coupled to an ICP-QMS with an octopole collision cell was employed for the multi-elemental speciation of essential elements (P, S, Cr, Mn, Fe, Co, Cu, Zn, Br, Se and I) and A1 as a toxic element in premature human milk. Comparison of speciation results demonstrates that premature human mothers milk differs significantly from formula milks in terms of the element binding pattern to the biomolecules. It was found that premature human milk is very rich in high molecular weight species associated with metals. The authors concluded that more attention must be paid to the chemical form in which essential elements are added to the formulas, particularly those used for the nutrition of premature babies.  

Chromium, iron and selenium in foodstuffs from animal sources have been analyzed after closed vessel microwave digestion by collision cell ICP-MS. The hmits of quantification (LOQ) of the analytical procedure were estimated under optimized experimental conditions with 0.025, 0.086 and 0.041 mgkg for Cr, Fe and Se, respectively. The results obtained for the three elements in nine different certified reference materials were, in aU cases, in good agreement with the certified values.  

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