Rubidium determination

Ross filter method, 108, 109 Rowland grating, concave, 121 Rubidium, determination by x-ray emission spectrography, 328 Ruthenium, determination by x-ray emission spectrography, 328... 

Rubidium determination in biological samples is also possible by the isotope dilution method (Labitajs 1992) or X-ray fluorescence spectrometry (Haneklaus etal. 1994). 

All the cations of Group I produce a characteristic colour in a flame (lithium, red sodium, yellow potassium, violet rubidium, dark red caesium, blue). The test may be applied quantitatively by atomising an aqueous solution containing Group I cations into a flame and determining the intensities of emission over the visible spectrum with a spectrophotometer Jlame 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. 

Rubidium-87 emits beta-particles and decomposes to strontium. The age of some rocks and minerals can be measured by the determination of the ratio of the mbidium isotope to the strontium isotope (see Radioisotopes). The technique has also been studied in dating human artifacts. Rubidium has also been used in photoelectric cells. Rubidium compounds act as catalysts in some organic reactions, although the use is mainly restricted to that of a cocatalyst. 

Ammonium may be determined by predpitation with sodium tetraphenylborate as the sparingly soluble ammonium tetraphenylborate NH4[B(C6H5)4], using a similar procedure to that described for potassium it is dried at 100°C, For further details of the reagent, including interferences, notably potassium, rubidium, and caesium, see Section 11.38,... 

Kemmel V, Taleb O, Andriamampandry C, et al Gamma-hydroxybutyrate receptor function determined stimulation of rubidium and calcium movements from NCB-20 neurons. Neuroscience 116 1021—1031,2003... 

Achener, P. Y., 1964, The Determination of the Latent Heat of Vaporization, Vapor Pressure, Enthalpy, and Density of Liquid Rubidium and Cesium up to 1,800°F, Proc. 1963 High Temperature Liquid Metal Heat Transfer Technology Meeting, Vol. 1, pp. 3-25 USAEC Rep. ORNL-3605. (2) Achener, P. Y, 1965, The Determination of the Latent Heat of Vaporization, Vapor Pressure of Potassium from 1,000-1,900°F, Aerojet-General Nucleonics Rep. AGN-8141. (2)... 

The element revealed itself through spectacular violet-colored flames and several red spectral lines. The metal melts at 38 °C, is very soft, and extremely reactive (burns in air and reacts violently with water). Rubidium is stored under mineral oil. It is suitable as a scavenger (oxygen capture) in vacuum tubes, where it is deposited on the glass as a mirror. It can also be found in photocells and phosphors for screens (for example, for air-traffic controllers. Not physiologically important. The radioactive rubidium-87 is useful for age determination in geochronology (half-life ca. 50 billion years). 

Shen and Ii [149] extracted caesium (and rubidium) from brine samples with 4-tert-butyl-2-(a methyl-benzyl) phenol prior to atomic absorption spec-trometric determination of the metal. 

Schoenfeld and Held [539] used a spectrochemical method to determine rubidium in seawater. They determined concentrations of rubidium in the range 0.008-0.04 p,g/ml in the presence of varying proportions and concentrations of other salts as internal standard. The coefficient of variation ranged from 7 to 25% for simulated seawater standards. 

Isotope dilution mass spectrometry has been used to determine traces of rubidium in seawater [540]. 

Rubidium has b een determined in seawater by X-ray fluorescence spectrometry with a detection limit of 2 - 4 xg of rubidium. The rubidium was coprecipitated withN3K2[Fe(CN6)]2 [541]. 

Vandecasteele et al. [745] studied signal suppression in ICP-MS of beryllium, aluminium, zinc, rubidium, indium, and lead in multielement solutions, and in the presence of increasing amounts of sodium chloride (up to 9 g/1). The suppression effects were the same for all of the analyte elements under consideration, and it was therefore possible to use one particular element, 115indium, as an internal standard to correct for the suppressive matrix effect, which significantly improved experimental precision. To study the causes of matrix effect, 0.154 M solutions of ammonium chloride, sodium chloride, and caesium chloride were compared. Ammonium chloride exhibited the least suppressive effect, and caesium chloride the most. The results had implications for trace element determinations in seawater (35 g sodium chloride per litre). 

This technique has been used to determine a number of elements in seawater, including lithium [826], barium [74], lead [827], rubidium [840], uranium [828], and copper [298,299]. It has not been extensively applied. 

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. 

The method, also called heavy atom method, consists in introducing a heavy atom in the molecule. Then X-rays with a wave length close to the X-ray absorption of the heavy atom is introduced. As a result a phase shift is superimposed on the ordinary diffraction pattern and configuration is then deduced. The method was first employed in 1951 by Bijvoet et al. to examine sodium rubidium tartrate who concluded that it is possible to differentiate between the two optically active forms. In other words it was possible to determine the absolute configuration of the enantiomers. Since then the absolute configurations of about two hundred optically active compounds have been elucidated by their correlation with other substances of known configuration. 

In terms of die original discussion of Section II, what one needs to know is the orientation of die chiral molecule in a chiral crystal relative to die crystal axes. The absolute orientation of the molecule or of a sequence of molecules in the crystal can be determined by high-resolution electron microscopy, especially in cases like rubidium tartrate or other organometallics in which die problem is to determine the relative position of die heavy metal km with respect to die... 

They produce distinctive colored flames when burned lithium = crimson sodium = yellow potassium = violet rubidium = purple cesium = blue and the color of francium s flame is not known. Many of francium s characteristics have not been determined owing to the fact that it is rare and all of its many radioactive isotopes have short half-lives. 

Redtors (R4) Rubidium 86 11 0.5-1.4, mean =1.1 0.7-1.9, mean = 1.6 24 Hours N.B. Both optimum and toxic levels were determined on each subject... 

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