Microelements Determination And Speciation Analysis In Eggs By ICP-AES/MS And The Hyphanted Technique

There are many kinds of micronutrient elements contained in foods that are vital to human health. The strong dependence of the toxicity and bioavailability of microelement upon their chemical forms has made the speciation and bioavailability vital to the food quality control and nutrition evaluate.The rapid development of inorganic instrumental analysis enabled the analytical community to look into the role of trace elements in different areas, such as health and environment, geochemistry and material sciences. Inductively coupled plasma mass spectrometry (ICP-MS) as an effective detection system for separation techniques plays an important role in speciation analysis, during the last 10 years speciation analysis was mainly driven by the possibilities provided by ICP-MS.The application of inductively coupled plasma atomic emission spectrometry/ mass spectrometry (ICP-AES/MS) and the hyphenated technique in the analysis of total concentration and speciation of elements contained in eggs were studied in this paper. Several commercially available powdered egg samples and fresh egg samples from China and Poland markets were investigated.For the determination of total elements concentration, microwave digestion of egg samples with nitric acid and hydrogen peroxide followed by ICP-AES/MS was introduced. The differences between ICP-AES/MS in element analysis were compared here, such as detect limits, interference, operation, and so on. It is confirmed that both of the instrument have strong element analysis ability, compared with ICP-AES,ICP-MS can obtain low detect limits (ppt) and can determine isotope, but needs more times dilute for high concentration elements.In the speciation analysis, three sample extraction solutions have been studied: Tris-HC1 buffer, pancreatin and pepsin. Speciation of cobalt,iodine and selenium in the extracts were carried out by size-exclusion liquid chromatography coupled with ICP-MS. It is showed that Tris-HCl buffer was more effective to extract elements speciation from egg samples compared with enzyme extraction. In Tris-HCl buffer extract Cobalamine and two unknown cobalt speciation were detected in all of the white and yolk samples, iodide was also found in all of the samples,but the extracts of yolks exhibited also the presence of two unknown speciation that were absent in whites. However, the selenium speciation should be further studied. On the other hand, alumina powder was used for defating. It is showed that when the ratio of egg to alumina is 4 to 1, alumina can absorb the lipid effectively. The research could contribute to further understanding of the elements speciation.