Cobalt analysis

Bromo-2-pyridyla2o)-5-diethylamiQophenol (5-Br-PADAP) is a very sensitive reagent for certain metals and methods for cobalt have been developed (23). Nitroso-naphthol is an effective precipitant for cobalt(III) and is used in its gravimetric determination (24,25). Atomic absorption spectroscopy (26,27), x-ray fluorescence, polarography, and atomic emission spectroscopy are specific and sensitive methods for trace level cobalt analysis (see... 

The stoichiometric compositions may he determined from cobalt analysis of nitric acid extract of the solid material by AA, ICP, or other instruments. The structural form of sulfides and their composition may be analysed by x-ray diffraction or fluorescence methods. 

Nelstrop, L.J., Greenwood, P.A., Greenway, G.M., An investigation of electroosmotic flow and pressure pumped luminol chemiluminescence detection for cobalt analysis in a miniaturised total analytical system. Labchip 2001, 1, 138-142. 

A solution of cobalt 0.3 /salt solution, at pH 7, was stable for 28 days in polystyrene tubes (Barfoot and Pritchard, 1980). Blood specimens for cobalt analysis could be stored in plastic tubes for one week in a refrigerator in longer storages deep freezing was reported to be necessary (Angerer and Heinrich. 1984). 

Although this experiment is written as a dry-lab, it can be adapted to the laboratory. Details are given for the determination of the equilibrium constant for the binding of the Lewis base 1-methylimidazole to the Lewis acid cobalt(II)4-trifluoromethyl-o-phenylene-4,6-methoxysalicylideniminate in toluene. The equilibrium constant is found by a linear regression analysis of the absorbance data to a theoretical equilibrium model. 

Hydrogen Peroxide Analysis. Luminol has been used for hydrogen peroxide analysis at concentrations as low as 10 M using the cobalt(III) triethanolamine complex (280) or ferricyanide (281) as promoter. With the latter, chemiluminescence is linear with peroxide concentration from... 

Ref 2. The brazing filler metal is analyzed for those specific elements for which values are shown. If the presence of other elements is the amount of those elements is deterrnined to ensure that the maximum total of each is <0.15 wt%. Remainder of material is Cu. Value represents maximum. Remainder of material is Mn. Table 7. Chemical Composition Requirements for Nickel and Cobalt Filler Metals indicated in the analysis. ... 

Color. Many water samples have a yellow to brownish-yeUow color which is caused by natural substances, eg, leaves, bark, humus, and peat material. Turbidity in a sample can make the measurement of color uncertain and is usually removed by centrifiigation prior to analysis. The color is usually measured by comparison of the sample with known concentrations of colored solutions. A platinum—cobalt solution is used as the standard, and the unit of color is that produced by 1 mg/L platinum as chloroplatinate ion. The standard is prepared from potassium chloroplatinate (K PtCl ) and cobalt chloride (C0CI26H2O). The sample may also be compared to suitably caUbrated special glass color disks. 

Analysis of zinc solutions at the purification stage before electrolysis is critical and several metals present in low concentrations are monitored carefully. Methods vary from plant to plant but are highly specific and usually capable of detecting 0.1 ppm or less. Colorimetric process-control methods are used for cobalt, antimony, and germanium, turbidimetric methods for cadmium and copper. Alternatively, cadmium, cobalt, and copper are determined polarographicaHy, arsenic and antimony by a modified Gutzeit test, and nickel with a dimethylglyoxime spot test. 

Thermal Properties. The thermal stabiUty of cellulose esters is deterrnined by heating a known amount of ester in a test tube at a specific temperature a specified length of time, after which the sample is dissolved in a given amount of solvent and its intrinsic viscosity and solution color are deterrnined. Solution color is deterrnined spectroscopically and is compared to platinum—cobalt standards. Differential thermal analysis (dta) has also been reported as a method for determining the relative heat stabiUty of cellulose esters (127). 

Choline Bitartrate. This substance [87-67-2] is a white crystalline material possessing an acid taste. It melts at 149—I53°C. Analysis by cobaltous chloride shows more than 99% as the bitartrate. Free ethylene glycol is less than 0.25%, with free alkaU at 0.0%. 

The detection and determination of traces of cobalt is of concern in such diverse areas as soflds, plants, fertilizers (qv), stainless and other steels for nuclear energy equipment (see Steel), high purity fissile materials (U, Th), refractory metals (Ta, Nb, Mo, and W), and semiconductors (qv). Useful techniques are spectrophotometry, polarography, emission spectrography, flame photometry, x-ray fluorescence, activation analysis, tracers, and mass spectrography, chromatography, and ion exchange (19) (see Analytical TffiTHODS Spectroscopy, optical Trace and residue analysis). 

For colorimetric or gravimetric determination l-nitroso-2-naphthol can be used. For chromatographic ion exchange (qv), cobalt is isolated as the nitroso-(R)-salt complex. The cyanate complex is used for photometric determination and the thiocyanate for colorimetry. A rapid chemical analysis of... 

M. A. IT insky and G. Knorre proposed l-nitroso-2-naphthol as a reagent for cobalt and Zh.I. lotsich - magnesium diiodine acetylene as a reagent for carbonyl group. F.M. Flavitsky developed a method for qualitative analysis based on solid substances as well as a portable laboratory for qualitative analysis. G.V. Khlopin proposed a method for determining oxygen dissolved in water. 

In report discuss the methodical aspects determination of magnesium, manganese, cobalt, zinc to their joint presence in nitric, sulphuric, chloric salts, and peculiarity of the analysis using to solid solutions of the hydrated diphosphates. 

A composite material used for rock-drilling bits consists of an assemblage of tungsten carbide cubes (each 2 fcm in size) stuck together with a thin layer of cobalt. The material is required to withstand compressive stresses of 4000 MNm in service. Use the above equation to estimate an upper limit for the thickness of the cobalt layer. You may assume that the compressive yield stress of tungsten carbide is well above 4000 MN m , and that the cobalt yields in shear at k = 175 MN m . What assumptions made in the analysis are likely to make your estimate inaccurate ... 

Samples Analyzed by Inductively Coupled Plasma (ICP) Metals — Where two or more of the following analytes are requested on the same filter, an ICP analysis may be conducted. However, the Industrial Hygienist should specify the metals of interest in the event samples cannot be analyzed by the ICP method. A computer print-out of the following 13 analytes may be typically reported Antimony, Beryllium, Cadmium, Chromium, Cobalt, Copper, Iron, Lead, Manganese, Molybdenum, Nickel, Vanadium, Zinc. Arsenic — Lead, cadmium, copper, and iron can be analyzed on the same filter with arsenic. 

Two general types of sheet steel are in current use, viz. cold-rolled mild steel and decarburised steel. A typical analysis for cold-rolled steel is 0-1% C, 0-5% Mn and 0-04% S. It can be obtained in regular, deep drawing or extra-deep drawing grades. This type of steel is normally used with a ground-coat including cobalt and nickel, as shown in Table 16.1. 

Scheme 1 outlines the retrosynthetic analysis of the Woodward-Eschenmoser A-B variant of the vitamin B12 (1) synthesis. The analysis begins with cobyric acid (4) because it was demonstrated in 1960 that this compound can be smoothly converted to vitamin B12.5 In two exploratory corrin model syntheses to both approaches to the synthesis of cobyric acid,6 the ability of secocorrinoid structures (e. g. 5) to bind metal atoms was found to be central to the success of the macrocyclization reaction to give intact corrinoid structures. In the Woodward-Eschenmoser synthesis of cobyric acid, the cobalt atom situated in the center of intermediate 5 organizes the structure of the secocorrin, and promotes the cyclization... 

The method may also be applied to the analysis of silver halides by dissolution in excess of cyanide solution and back-titration with standard silver nitrate. It can also be utilised indirectly for the determination of several metals, notably nickel, cobalt, and zinc, which form stable stoichiometric complexes with cyanide ion. Thus if a Ni(II) salt in ammoniacal solution is heated with excess of cyanide ion, the [Ni(CN)4]2 ion is formed quantitatively since it is more stable than the [Ag(CN)2] ion, the excess of cyanide may be determined by the Liebig-Deniges method. The metal ion determinations are, however, more conveniently made by titration with EDTA see the following sections. 

Murexide forms complexes with many metal ions only those with Cu, Ni, Co, Ca and the lanthanides are sufficiently stable to find application in analysis. Their colours in alkaline solution are orange (copper), yellow (nickel and cobalt), and red (calcium) the colours vary somewhat with the pH of the solution. 

Notes. (1) A suitable solution for practice analysis may be prepared by dissolving about 5.0 g of accurately weighed, pure, ammonium cobalt sulphate in water and diluting to 500 mL in a graduated flask. Use 25 mL for each determination. 

SEPARATION OF NICKEL AND COBALT BY COULOMETRIC ANALYSIS AT CONTROLLED POTENTIAL... 

Cobalt, sepn. of from nickel, (cm) 532 Codeine and morphine, D. of 740 Coefficient of variation 135 Colloidal state 418 See also Lyophilic, Lyophobic Colorimeters light filters for, 661 photoelectric, 645, 666 Colorimetric analysis 645 criteria for, 672 general remarks on, 645, 672 procedure, 675 solvent selection, 674 titration, 652... 

The potential usefulness of x-ray emission spectrography for trace analysis is implicit in the results of approximate calculations presented in Chapter 4. Thus, it was estimated that the intensity of cobalt Ka generated under practicable conditions in a monolayer (area, 1 sq cm) of cobalt atoms might give 133 counts per second (4.16). Such a sample weighs 0.2 pg. 

Cobalt, in solution, determination by x-ray emission spectrography, 255 trace analysis by x-ray emission spectrography, 126, 127, 159, 163, 225-229, 235... 

Thickness gaging, of steel strip, 69-71 use of cobalt-60 for, 291 Thick-target x-ray spectra, 6, 7, 99-101 Thin films, thickness determined by characteristic line intensity, 153 Thin samples, analysis by x-ray emission spectrography, 167... 

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