Gold-containing materials

Not every gold-induced skin disorder is necessarily wholly disfiguring in one curious case, the patient was seen to glitter with tiny specks of a gold-coloured (and gold-containing) material covering the skin of the neck, upper arms, and back (64). 

The fat-soluble vitamins are photosensitive, and therefore all operations with vitamin solutions and vitamin-containing materials should be carried out in subdued light or in low-actinic amber glassware. Ideally, the laboratory or a dedicated room within the laboratory should have the windows (if any) covered with effective blinds, and artificial lighting should be provided by F40GO gold (or equivalent) fluorescent lamps, which exclude radiation wavelengths of less than 500 nm. 

For materials with low melting point, such as gold, the material is filled into a small heat-resistant container (evaporation boat) usually made of tungsten or tantalum. The... 

Some gold-containing polymers incorporating isocyanide assembling ligand on one side and an alkynyl moiety on the other side were described by Puddephatt and collaborators.56 Again these materials were compared to model compounds (Fig. 22). 

A gold-based material has been formulated for use as a three-way catalyst in gasoline and diesel applications.28 This catalyst, developed at Anglo American Research Laboratories in South Africa, consisted of 1% Au supported on zirconia-stabilized-Ce02, ZrC>2 and TiC>2, and contained 1% CoOx, 0.1% Rh, 2% ZnO, and 2% BaO as promoters. The catalytically active gold-cobalt oxide clusters were 40-140 nm in size. This catalyst was tested under conditions that simulated the exhaust gases of gasoline and diesel automobiles and survived 773 K for 157 h, with some deactivation (see Section 11.2.7). 

The analysis of metal artifacts has been used extensively to differentiate materials by sources. X-ray fluorescence and neutron activation analysis have both proved valuable in determining elemental concentrations. Native metals, such as gold, contained impurities that could, in some cases, be used to characterize their sources. However, the smelting of ores to recover the metals often changed the concentrations of impurities. Later, as alloys (e.g., bronze and brass) were produced, the compositions were intentionally altered and controlled. In some cases, the re-use of materials or the lack of quality control made the alloy composition quite variable (especially in terms of the trace components). 

When interpreting the results, however, it is important to bear in mind the possibility that the thermal effects observed are influenced by the interaction of the container material and the sample. If the chemical structure indicates this possibility, these first runs should be followed by further tests using chemically inert sample containers. The variety ranges today from pure glass containers, those with gold or Teflon coating to pure carbon containers. The use of such containers, however, is usually accompanied either by pressure or temperature measuring constraints. 

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