Clinical and biological materials, foods and beverages

Abstract

This Update refers to papers published approximately between September 2005 and August 2006. In a new development we have introduced a section specifically to discuss the emerging field of metallomics. This allows the inclusion not just of the essential analytical work but also applications involving the structural and functional roles of metals and metalloids. This work is directed towards understanding the metabolism of elements, their involvement in the biochemistry of molecules such as proteins and nucleic acids, and their mechanisms of action. In the period covered by this review we can see the development of several elegant but complex methods to provide for an integral approach which links the quantitative analysis with information about structural and functional activity. At a time when analytical equipment is so sophisticated it should not be necessary to ask questions on the validity of published results. However, as those who review submitted papers will appreciate, this can never be taken for granted and it has been demonstrated that the quality of data (judged by the spread of ‘normal results’) is related to the attention devoted to quality control in the written report. A number of new pieces of work were seen in this review period. Use of exhaled breath as a novel biological sample type was reported. A preconcentration column located in the arm of an autosampler used for ETAAS was applied to measurements of Pt in foods and beverages. Interferences associated with the determination of Cd in urine by ETAAS were removed with a neat piece of manipulation. The sample was placed in the furnace and Cd concentrated onto Pd modifier using an electrolytic process, after which the sample solution, together with interferents, was drawn back into the capillary and sent to waste. The popularity of ICP-MS continues to grow, largely fuelled by collision cell applications and by work on getting the right gas for the job. Following on from the considerable Pb in bone work achieved with in vivo XRF, this technique is now being used to measure Cd, although the sensitivity requires improvement if normal concentrations are to be determined. Work on selenium is as popular as ever in both the clinical and food areas, with several reviews seen and fundamental work on sample stability, extraction, speciation, bioavailability, and the identification of novel compounds in yeast and other samples, many of which involve Se/S substitutions. Selenosugars are recognised as important metabolites and now arsenosugars have been identified. In recent years we have looked without much success for data related to organically produced food but now there are some data for milk. Of 45 elements measured, Mo was increased while Ba, Eu, Mn and Zn were reduced, when compared with conventional cow’s milk. Among the more unusual studies seen were measurements of Pb in alligator bones and essential elements in royal jelly.