Metal samples, preliminary tests

V.2 PRELIMINARY TESTS ON NON-METALLIC SOLID SAMPLES 1. Appearance The appearance of the substance should be carefully noted a lens or microscope should be used if necessary. Observe whether it is crystalline or amorphous, whether it is magnetic and whether it possesses any characteristic odour or colour. 

V.3 PRELIMINARY TESTS ON METAL SAMPLES The analysis of a metal or of an alloy is simplified by the fact that no anions need be looked for. Many alloys contain small amounts of P, Si, C, and S phosphorus is converted by the usual solution process into phosphate, and may be identified as such (Section IV.28). 

Small amounts of the individual fullerenes ( 0.5mg) were placed in quartz tubes with alkali metals and sealed under vacuum. These samples were subjected to a series of heat treatments and tests for superconductivity by 9-GHz microwave-loss experiments. Preliminary tests indicated that only the K-doped Cfto showed a response consistent with a superconducting transition (Fig. 1). For this reason, together with the fact that K Cgo showed the highest film conductivity, we focused our studies on the K-doped compound. 

Before starting the preparation of the candidate CRM, a preliminary test was carried out on a small sample of 50 g wet sediment, which was dried for 15 h at 60°C, ground in a porcelain mortar, homogenized for 10 min in a Turbula mixer and subsequently analyzed for various trace metals by Neutron Activation Analysis (NAA) (see Table 11.1) and for its particle size distribution (Figure 11.1), after which the powder was examined microscopically (Figure 11.2). This semi-quantitative check was carried out to verify the initial trace element levels in order to establish whether the preparation steps listed below could be carried out free of contamination and whether the resulting material was of the required quality ... 

Also known as incipient wetness, impregnation is the simplest and most direct method of deposition. The object is to fill the pores with a solution of metal salt of sufficient concentration to give the correct loading. Figure 6.18 shows the sequence of steps. The support, usually in particle form, is heated or evacuated to remove pore moisture. This is not essential but speeds diffusion of the solute into the pores. Solution, in an amount Just sufficient to fill the pores and wet the outside of the particles, is introduced. Although this may be calculated from measured pore volumes, it is sometimes more reliably determined with preliminary tests on aliquot samples. 

The small number of samples taken under heavy shelling, a few km from the front line are only a preliminary test and necessitates continuation of the study. Chemical partitioning of the heavy metals through soil constituents and variable retention ability of the soils regarding different metal ions will change the geochemical pattern on the surface and in the depth of the soil horizon with time [12-14]. Any method of decontamination. 

Because the new DFT techniques had not yet been applied to cluster-model calculations, many preliminary tests had to be performed to eliminate most uncertainty factors. First of all, from the variety of DFT functionals and the basis sets proposed in the literature one must select the combination which performs best for the system studied. This usually means that a large set of tests must be performed for a small sample representing the system of interest in the cluster caleulations. In the simplest approach, these tests can be performed by assuming that the metal cluster is re-... 

Any analysis of a real sample must begin with a preliminary examination of the material, which could be (a) a liquid (usually a solution), (b) a solid, non-metallic substance, (c) a metal or an alloy, or (d) an insoluble material. The description of preliminary tests will be followed by hints on dissolution or fusion, as the main testing and separation has to be carried out in solution. 

If the sample is a metal, decide on the best solvent after the preliminary tests described in Section 5.4. The insoluble part, if any, should be treated according to Section 5.6. 

We have addressed the topic of metal bioavailability and metal toxicity in environmental samples. Traditionally, metal availability is investigated using a chemical approach. Afterwards, the concept of Water Effect Ratio (WER) was proposed by the U.S. EPA and employed bioassays (e.g., fish and invertebrate tests) to assess metal bioavailability and toxicity. In the HMBC approach discussed in this review, we have made use of a bacterial assay that is specific for metal toxicity to achieve this goal. This is only a preliminary survey of the potential applications of the HMBC concept. Some preliminary results on the use of MetPLATE for the fractionation of HMBC to obtain information on the factor(s) that control metal bioavailability in environmental samples were also presented. Using MetPLATE eliminates or diminishes the confounding factor represented by the presence of organic toxicants in a given sample. Further work is needed to refine the fractionation scheme. 

Reagent that has stood for a time after a bottle has been opened should be tested either in a preliminary run or by shaking a sample with ice water and rapidly titrating the free acetic acid. Fractionation affords pure anhydride material of practical grade should first be distilled from anhydrous sodium acetate to eliminate halogen compounds and metals. 

Before the start of static experiments with mercury on fish, a preliminary study was conducted on the mercury solution in a glass aquaria. It was provided with 60 1 of acclimation water in order to verify the elfective permanence in solution of Hg during the 96 h of static test by sampling the water at each metal concentration (0.1, 0.2 and 0.4, mg/1) every 24 h. The water samples were treated with a solution of 0.25 M H2SO4 and 0.3 M NaCI and stored at 4°C until analysis. 

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