Nickel analytical techniques

Analytical Methods. Carbon, hydrogen, nitrogen, and sulfur analyses and Hempel distillations (IS) were performed using conventional analytical techniques. Nickel and vanadium contents were determined by the methods of Bean (14). These methods involve the colorimetric determination of nickel dimethylglyoxime and tungstovanadic acid, respectively. Simulated distillations were done by the method of Poulson... 

Nickel also is deterrnined by a volumetric method employing ethylenediaminetetraacetic acid as a titrant. Inductively coupled plasma (ICP) is preferred to determine very low nickel values (see Trace AND RESIDUE ANALYSIS). The classical gravimetric method employing dimethylglyoxime to precipitate nickel as a red complex is used as a precise analytical technique (122). A colorimetric method employing dimethylglyoxime also is available. The classical method of electro deposition is a commonly employed technique to separate nickel in the presence of other metals, notably copper (qv). It is also used to estabhsh caUbration criteria for the spectrophotometric methods. X-ray diffraction often is used to identify nickel in crystalline form. 

In many aqueous solutions nickel has the ability to become passive over a wide range of pH values. The mechanism of passivation of nickel and the properties of passive nickel have been studied extensively—perhaps more widely than for any other element, except possibly iron. In recent years the use of optical and surface analytical techniques has done much to clarify the situation . Early studies on the passivation of nickel were stimulated by the use of nickel anodes in alkaline batteries and in consequence were conducted in the main in alkaline media. More recently, however, attention has been directed to the passivation of nickel in acidic and neutral as well as alkaline solutions. 

The following analytical techniques seem to be adequate for the concentrations under consideration copper and nickel by Freon extraction and FAA cold vapour atomic absorption spectrometry, cobalt by Chelex extraction and differential pulse polarography, mercury by cold vapour atomic absorption absorptiometry, lead by isotope dilution plus clean room manipulation and mass spectrometry. These techniques may be used to detect changes in the above elements for storage tests Cu at 8 nmol/kg, Ni at 5 nmol/kg, Co at 0.5 nmol/kg, Hg at 0.1 nmol/kg, and Pb at 0.7 nmol/kg. 

Analytical methods and detection limits for nickel in biological materials are reported in Table 6-1. The presence of nickel in other biological materials such as hair and nails can be determined by the same analytical techniques used for blood and tissue after suitable procedures for dissolving the sample have been utilized (Stoeppler 1980 Takagi et al. 1986, 1988). 

Chronopotentiometry, galvanostatic transients, 1411 as analytical technique, 1411 activation overpotential, 1411 Clavilier, and single crystals, 1095 Cluster formation energy of, 1304 and Frumkin isotherm, 1197 Cobalt-nickel plating, 1375 Cold combustion, definition, 1041 Cole-Cole plot, impedance, 1129, 1135 Colloidal particles, 880, 882 and differential capacity, 880 Complex impedance, 1135 Computer simulation, 1160 of adsorption processes, 965 and overall reaction, 1259 and rate determining step, 1260... 

Relatively few reports of the catalysed reactions of n-butenes with hydrogen were extant up to the early 1960 s. Those studies which had been performed were mainly concerned with nickel as catalyst. The major problem was the difficulty of chemical analysis of the reaction products. However, with the advent of gas chromatography as a general analytical technique, the analysis of reaction products has become a relatively simple task and, accordingly, over the last 15 years the hydrogenation of higher olefins has received considerable attention. 

The availability of instrumentation in the QC laboratory or at the production facility will often influence the choice of the analytical technique. For example, the trace analysis of a DS for three different metal elements (iron, copper, and nickel) can be simultaneously performed by an inductively coupled plasma (ICP). The cost of this instrument, however, is 100,000 or more. For this example, the same analysis can be performed to the level of precision and detection defined in the technical objective by an A A spectrometer. Unlike the ICP, the AA analysis is sequential, and therefore is significantly more time-consuming. The choice of the A A method may be desirable, however, since the instrumentation cost is afraction ofthe cost of an ICP, and often is an instrument already available in a QC or production laboratory. 

Elated steel screws. No corrosion was found with the new screws, and the [F was found to be in proper stoichiometric amount within the experimental error of the analytical technique. The heat of reaction, using the nickel-plated steel screws, agreed within experimental error with the results which had been corrected for the small amount of corrosion. 

Seven previously analyzed Claudian quadrantes (9) are fairly close in composition to the ones reported in this chapter. However, improved analytical techniques and use of a better x-ray fluorescence spectrometer for nickel, silver, and lead analyses have produced results that are probably more accurate than the previous ones. 

The susceptibility of solid surfaces to contamination often results in a requirement for an ultrahigh vacuum (UHV) chamber for preparation and observation of particular samples. For many materials, including metals such as platinum and nickel, adsorption of hydrocarbons and chemisorption of oxygen are quite fast at atmospheric pressure, and the surface must be isolated in UHV to prevent rapid degradation. In addition, a sample in UHV may be subjected to surface analytical techniques such as X-ray photoelectron and Auger spectroscopy to verify or corroborate Raman results. As a result, much of the early and well-characterized surface Raman experiments were carried out in UHV chambers operating below 10 torr (12). 

Stoeppler. M., 1983. General analytical aspects of the determination of lead, cadmium, and nickel in biological fluids. In Facchetti, S. (Ed.), Analytical Techniques for Heavy Metals in Biological Fluids. Elsevier, Amsterdam. 

The structural transformation between austenite and martensite occurs when the mechanical stress attains a certain level, or with an appropriate temperature change, A reversible twinning process takes place at the atomic level, which can result in superelastic behaviour and shape memory [8], The properties of the nickel-titanium endodontic instruments and orthodontic wires depend critically upon the nature and proportions of the NiTi phases in their microstructures, as discussed in the following sections. While X-ray diffraction has been used to study the phases in nickel-titanium endodontic instruments [15,16] and orthodontic wires [7,17,18], this analytical technique is limited to a near-surface region less than 50 pm in depth for metallic materials [19], and study of the phase transformations with temperature is not generally convenient. In contrast, DSC can provide information about the phases present in bulk nickel-titanium endodontic instruments and orthodontic wires with facility, and the effect of temperature changes on the NiTi phase transformations is easily studied. 

Nickel has been found essential for nutrition in pigs, also rats (Nielsen, 1975). The essential quantity is so much smaller than was required for the earlier-established essential metals, that searchers had to wait for the discovery of new analytical techniques, such as neutron activation. The enzyme urease (in beans) is nickel-dependent (Dixon et al, 1975). Several bacteria have reductases that need nickel, such as Methanobacterium and Desulphovibrio (Thauer, 1980), and so do bacterial carbon monoxide dehydrogenases (Deake, Hu and Ward, 1980). 

There is often a need to monitor cyanide in air, water, solid waste, food, and other environmental samples. The cyanide present in these samples may include free (noncomplexed) cyanide such as hydrogen cyanide (or hydrocyanic acid in water solution), cyanogen (C2N2), cyanogen chloride, cyanide salts, or complexed cyanide such as metal-cyanide complexes of iron, nickel, copper, mercury, silver. Complexed cyanides are less toxic because they are less bioavail-able, but they may break down producing free cyanide, for example, as a result of the ultraviolet radiation in daylight. Analytical techniques for free... 

As discussed in recent reviews [63-66], graphite furnace atomic absorption spectrometry (GFAAS) and differential pulse anodic stripping voltammetry (DPASV) are practical, reliable techniques that furnish the requisite sensitivity for measurement of nickel concentrations in biological samples. The most practical analytical technique for the determination of nickel in biological specimen... 

Other heavy metals nickel (Nielsen and Ollerich, 1974), and tin (Schwarz, Milne, and Vinard, 1970) are claimed as essential for animal nutrition. Modern refinements in analytical technique, such as neutron activation analysis, were needed to establish these recent claims, because the quantities present are so much smaller than with the earlier discovered essential metals. The enzyme urease seems to be nickel-dependent (Dixon et al. ... 

The application of the Chelex 100 resin separation and preconcentration, with the direct use of the resin itself as the final sample for analysis, is an extremely useful technique. The elements demonstrated to be analytically determinable from high salinity waters are cobalt, chromium, copper, iron, manganese, molybdenum, nickel, scandium, thorium, uranium, vanadium, and zinc. The determination of chromium and vanadium by this technique offers significant advantages over methods requiring aqueous final forms, in view of their poor elution reproducibility. The removal of sodium, chloride, and bromide allows the determination of elements with short and intermediate half-lives without radiochemistry, and greatly reduces the radiation dose received by personnel. This procedure was successfully applied in a study of... 

With analytical methods such as x-ray fluorescence (XRF), proton-induced x-ray emission (PIXE), and instrumental neutron activation analysis (INAA), many metals can be simultaneously analyzed without destroying the sample matrix. Of these, XRF and PEXE have good sensitivity and are frequently used to analyze nickel in environmental samples containing low levels of nickel such as rain, snow, and air (Hansson et al. 1988 Landsberger et al. 1983 Schroeder et al. 1987 Wiersema et al. 1984). The Texas Air Control Board, which uses XRF in its network of air monitors, reported a mean minimum detectable value of 6 ng nickel/m (Wiersema et al. 1984). A detection limit of 30 ng/L was obtained using PIXE with a nonselective preconcentration step (Hansson et al. 1988). In these techniques, the sample (e.g., air particulates collected on a filter) is irradiated with a source of x-ray photons or protons. The excited atoms emit their own characteristic energy spectrum, which is detected with an x-ray detector and multichannel analyzer. INAA and neutron activation analysis (NAA) with prior nickel separation and concentration have poor sensitivity and are rarely used (Schroeder et al. 1987 Stoeppler 1984). 

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