Rubidium analysis

Rubidium Analysis, Biological Studies and Occurrence," Chemical Abstracts— Chemical Substances Indexes, American Chemical Society, Washington, D.C. 

The operation of each column was essentially identical. First the column was loaded with the cesium feed at the rate of 2 column volumes per hour (2 Cv/hr). The column then was scrubbed with 8 Cv of a 0.15M (NH4)2CO3-0.1M NH4OH solution at 2 Cv/hr. Next the column was eluted with a 3M (NH4)2C03-2Af NH4OH solution at 2 Cv/hr. Finally, the column was washed with 4 Cv of water before the next loading cycle. Downflow was used for all column operations, and the column temperature was maintained at approximately 25 °C. Each column volume of effluent was analyzed for cesium by in-cell gamma energy analysis. The entire eluent effluent was combined after each run and sampled for sodium, potassium, and rubidium analysis by flame photometry. 

Rubidium metal is commeicially available in essentially two grades, 99 + % and 99.9 + %. The main impurities ate other alkali metals. Rubidium compounds are available in a variety of grades from 99% to 99.99 + %. Manufacturers and suppliers of mbidium metal and mbidium compounds usually supply a complete certificate of analysis upon request. Analyses of metal impurities in mbidium compounds are determined by atomic absorption or inductive coupled plasma spectroscopy (icp). Other metallic impurities, such as sodium and potassium, are determined by atomic absorption or emission spectrograph. For analysis, mbidium metal is converted to a compound such as mbidium chloride. 

In addition to the above oxides M2O, M2O2, M4O6, MO2 and MO3 in which the alkali metal has the constant oxidation state 4-1, rubidium and caesium also form suboxides in which the formal oxidation state of the metal is considerably lower. Some of these intriguing compounds have been known since the turn of the century but only recently have their structures been elucidated by single crystal X-ray analysis. Partial oxidation of Rb at low temperatures gives RbeO which decomposes above —7.3°C to give copper-coloured metallic crystals of Rb902 ... 

Nineteen bone samples were prepared for analysis of the trace elements strontium (Sr), rubidium (Rb), and zinc (Zn). The outer surface of each bone was removed with an aluminum oxide sanding wheel attached to a Dremel tool and the bone was soaked overnight in a weak acetic acid solution (Krueger and Sullivan 1984, Price et al. 1992). After rinsing to neutrality, the bone was dried then crushed in a mill. Bone powder was dry ashed in a muffle furnace at 700°C for 18 hours. Bone ash was pressed into pellets for analysis by x-ray fluorescence spectrometry. Analyses were carried out in the Department of Geology, University of Calgary. 

Nixon277 compared atomic absorption spectroscopy, flame photometry, mass spectroscopy, and neutron activation analysis as methods for the determination of some 21 trace elements (<100 ppm) in hard dental tissue and dental plaque silver, aluminum, arsenic, gold, barium, chromium, copper, fluoride, iron, lithium, manganese, molybdenum, nickel, lead, rubidium, antimony, selenium, tin, strontium, vanadium, and zinc. Brunelle 278) also described procedures for the determination of about 20 elements in soil using a combination of atomic absorption spectroscopy and neutron activation analysis. 

Helmke PA, Sparks DL. Lithium, sodium, potassium, rubidium, and cesium. In Bartels JM (ed.), Methods of Soil Analysis Part 3 Chemical Methods. Madison, WI ... 

Example The intensity of atomic absorption lines for the alkali metals, such as potassium (K) rubidium (Rb) and caesium (Cs), is found to be affected by temperature in a complex way. Under certain experimental parameters a noticeable decrease in absorption may be observed in hotter flames. Hence, lower excitation temperatures are invariably recommended for the analysis of alkali metals. 

Note added in proof Tetranactin and its sodium, potassium, and rubidium complexes have been the subject of crystal structure analysis. (Iitaka, Y., Sakamaki,... 

A quite new type of antibiotic and one of the few naturally-occurring boron compounds is boromycin (86). Hydrolytic cleavage of D-valine with the M(7) hydroxides gave caesium and rubidium salts of this antibiotic, and crystal structure analysis established the formula as (XIIT). The rubidium ion is irregularly coordinated by eight oxygen atoms. Experiments with models showed that the cation site would be the natural place for the—NH3+ end of the D-valine residue, and the whole structure raises the possibility that transport of larger alkali metals is related to the N-ends of peptides and proteins. 

Elemental analysis Rb 70.68%, Cl 29.32%. Aqueous solution of rubidium chloride may be analyzed for rubidium by AA or ICP and for the chloride anion by ion chromatography or titration with a standard solution of silver... 

Many elements are present in the earth s crust in such minute amounts that they could never have been discovered by ordinary methods of mineral analysis. In 1859, however, Kirchhoff and Bunsen invented the spectroscope, an optical instrument consisting of a collimator, or metal tube fitted at one end with a lens and closed at the other except for a slit, at the focus of the lens, to admit light from the incandescent substance to be examined, a turntable containing a prism mounted to receive and separate the parallel rays from the lens and a telescope to observe the spectrum produced by the prism. With this instrument they soon discovered two new metals, cesium and rubidium, which they classified with sodium and potassium, which had been previously discovered by Davy, and lithium, which was added to the list of elements by Arfwedson. The spectroscopic discovery of thallium by Sir William Crookes and its prompt confirmation by C.-A. Lamy soon followed. In 1863 F. Reich and H. T. Richter of the Freiberg School of Mines discovered a very rare element in zmc blende, and named it indium because of its brilliant line in the indigo region of the spectrum. 

German physicist and physical chemist. Professor of physics at Heidelberg and Berlin. Independent discoverer of the Kirchhoff-Stewart law of radiation and absorption. He explained the Fraunhofer lines of the solar spectrum, and, with Bunsen, founded the science of spectroscopic analysis and discovered the elements cesium and rubidium. 

Cheary, R. W. 1987. A structural analysis of potassium, rubidium and caesium substitution in barium hollandite. Acta Crystallographica, B43, 28-34. 

The principal rubidium salts which would probably have been present in the sediment (chloride, sulfate, bicarbonate, etc.) are all soluble in water. As discussed later, the red clay was thoroughly dialyzed prior to use (including prior to analysis by emission spectroscopy). Any rubidium salts initially present in the clay samples would, therefore, have been removed by the dialyzing solution. Hence, it was assumed that the rubidium concentration given in Table I represented sorbed rubidium which had been in equilibrium with the rubidium in the original interstitial seawater. Then when calculating distribution coefficients from experimental data, the concentration given in Table I was used as the initial clay-phase rubidium concentration, rather than zero as used with most of the other species studied. 

The isotope 40K can be analyzed in natural water samples with the Cherenkov counting technique.2 3 Because of the lack of a suitable radiotracer for K and the similarity between the chemistries of rubidium and potassium, 86Rb can be used as a tracer for K.4 Also, thermal ionization mass spectrometry (TIMS) has been used to determine 40K in environmental samples. The interference of mass 40 can be solved by double spiking with 43Ca/48Ca the procedure for the routine high-precision isotope analysis of the K-Ca system will then be free of Ca fractionations.5... 

Since the principal impurities in cesium compounds are other alkali metals, analysis by conventional methods is difficult. Unrecrystallized cesium iododichloride prepared by this method was analyzed spectroscopically and found to contain 0.01 to 1.0% rubidium and traces of other metals. 

The existence of these different practices was not sufficient to create a discipline or subdiscipline of physical chemistry, but it showed the way. One definition of physical chemistry is that it is the application of the techniques and theories of physics to the study of chemical reactions, and the study of the interrelations of chemical and physical properties. That would mean that Faraday was a physical chemist when engaged in electrolytic researches. Other chemists devised other essentially physical instruments and applied them to chemical subjects. Robert Bunsen (1811—99) is best known today for the gas burner that bears his name, the Bunsen burner, a standard laboratory instrument. He also devised improved electrical batteries that enabled him to isolate new metals and to add to the list of elements. Bunsen and the physicist Gustav Kirchhoff (1824—87) invented a spectroscope to examine the colors of flames (see Chapter 13). They used it in chemical analysis, to detect minute quantities of elements. With it they discovered the metal cesium by the characteristic two blue lines in its spectrum and rubidium by its two red lines. We have seen how Van t Hoff and Le Bel used optical activity, the rotation of the plane of polarized light (detected by using a polarimeter) to identify optical or stereoisomers. Clearly there was a connection between physical and chemical properties. 

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