β Scribed by R. Cornelis; F. Borguet; J. De Kimpe
No coin nor oath required. For personal study only.
Speciation of trace elements in body fluids and tissues consists of defining the many biocomponents to which the trace elements are bound and to explain their mobility, storage, retention and toxicity. Such new frontiers are now open for interdisciplinary research. It is necessary to maintain the integrity of the metal-ligand binding and to check the mass balance of the protein and the trace element throughout the isolation steps. A distinction is made between chemical speciation of the trace element and speciation as a part of cytology. Some methods are discussed for the speciation of As and Cr in serum, together with the limitations of the speciation procedure. It is assumed that the biomolecule and the trace element which are subsequently detected in the same fraction, are indeed associated with one another. This is not necessarily the case, so that confirmation with different means of identification of the biocomponent is imperative. A major problem in speciation work is due to the fact that immense hazards exist for contamination and losses of the trace element. In cytology, meaningful speciation cannot be achieved by ultracentrifugation of the different cell organelles. The best approach nowadays is to use microbeam techniques which are able to locate the trace element in situ, and even to attribute a semiquantitative value to its presence. Keyworub: Gel permeation chromatography; Speciation of trace elements; Trace element speciation Today, very few physicians, if any, would request a total iodine content of a plasma sample. This type of analysis, which was based on the Sandell-Kolthoff reaction [Ce(IV)-As(II1) catalysis, with first order reaction rate based on the iodide concentration] [l], has been deleted from the list of standard procedures for the routine clinical laboratory. It has been replaced by measurement of the concentrations of the thyroid hormones T3, T4 and related hormonal compounds. These became the parameters to control the thyroid function and so the I-stores of the body. Iodine provides a good example of a trace
π SIMILAR VOLUMES
Speciation of trace metals in sediments M. KERSTEN 11.1 calibration curve proved to reproduce known Cr III /Cr VI ratios of pure Cr 2 O 3 and Na 2 CrO 4 ΠΈ H 2 O mixtures with an accuracy of 3%. It can also be used to estimate Cr VI /total Cr content, e.g. in contaminated soils with chromium levels a
A method for speciation of trace metals at natural concentration levels has been developed. The speciation is carried out in a cleanroom laboratory and the determination is performed with an ICP-MS. The method is based on fractionation of metal species on three adsorbents, Chelex-100, Sep-Pak C-18 a