Plasma rubidium

At least 90% of rubidium measured in whole blood is located in erythrocytes [32,33] and therefore the concentration of rubidium in whole blood is always higher than in plasma. Although plasma levels are essentially similar in men and women (1.97 p.mol/liter), a large variation in plasma rubidium exists among individuals [33-35]. Consequently, for clinical analysis of rubidium levels, erythrocytes or whole blood is preferable to plasma or serum. 

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. 

Ultracold neutral plasmas may be produced by laser cooling and trapping of different types of neutral atoms [105] such as calcium, strontium, rubidium, cesium etc., by photoionizing Bose condensates [106] and also by spontaneous ionization of dense Rydberg atoms [107,108]. A review on ultracold neutral plasmas due to Killan et al. [61] gives an excellent disposition on the subject. 

A method has been published for the determination of a variety of metals in diluted blood and serum using inductively coupled plasma atomization with mass spectrometric detection.3 Blood was diluted tenfold and serum fivefold with a solution containing ammonia, Triton X-100 surfactant, and EDTA. Detection limits adequate for measurement in blood or serum were found for cadmium, cobalt, copper, lead, rubidium, and zinc. 

Can be used in the flame or flameless mode. In the latter instance, a very low fuel (hydrogen) flow is used to form a plasma around a heated bead of potassium or rubidium salts. This results in a reduced response to hydrocarbons and subsequently less interference. Halogens as well as organolead compounds respond to the NPD detector in the flame mode. Phosphates (from cleaning detergents), chlorinated solvents and silanizing reagents can deplete the alkali beads and should thus be avoided ... 

An alkali metal bead, usually rubidium sulfate, is positioned above the jet in NPD, as seen in Fig. 2, and the current is applied to this bead, which causes it to achieve temperatures up to 800°C. The addition of hydrogen and air generates plasma around the bead, and carrier gas containing the solutes is delivered to the tip of the jet and the plasma. Specific ions are produced in the plasma from nitrogen- or phosphorus-containing compounds. These ions move to the charged collector. This movement of ions generates a current that is measured... 

Nitrogen-phosphorus detector (NPD) Figure 13.6 is a schematic digram of a typical nitrogen-phosphorus detector (also known as the thermionic detector). An electrically heated silicate bead doped with an alkali (such as rubidium) salt is mounted between the jet and the collector. Hydrogen at very low flow-rate (typically 2 ml/min) is mixed with the carrier gas and bums as a plasma (very hot gas) flame as it makes contact with the heated bead. The collector is maintained at a positive electrical polarity with respect to the bead and jet. 

The addition of heparin to the isolated rat diaphragm previously loaded with rubidium 86 results in change of the inflow of rubidium . Heparin has a permeabilizing action which appears to be due to mobilization of bound potassium and this can be related to a reduction of calcium in the perfusion solution. Karasek and Mourek.i conclude that heparin depresses oxidative processes through an effect on cell permeability it is possible that it adsorbs certain substances such as potassium chloride or acetylcholine. In extracorporeal dialysis , heparin causes an apparent decrease of 60 per cent in plasma calcium concentration. Heparin also forms a chelate-like compound with calcium ions " . This process is usually unimportant as heparin absorbs a maximum of only 5 per cent of its weight of calcium, but with intradermal, intramuscular or subcutaneous administration, heparin may deplete the capillary walls of calcium and cause them to become fragile. Heparin alsc decreases wound strength 6-14 days after operation in some experiments and may delay the union of fractures in bone repair . Heparin, but not chondroitin sulphate or hyaluronic acid, in tissue culture increases the amount of bone resorption in the presence of suboptimal concentrations of parathyroid extracts, and thus may be a cofactor in bone metabolism. ... 

After oral administration of RbCl, peak rubidium plasma levels are generally attained 60-90 min later. The metal is then rapidly distributed to other tissues. Although rubidium follows the potassium pathway within the body, there are sufficient differences in membrane selectivity to result in different patterns of retention and secretion. The highest rates of uptake occur (in decreasing order) in liver > lymph nodes > striatal muscle > heart, kidney, and lung [26]. Erythrocytes show a maximum uptake within 30 min and maintain elevated levels despite rapidly diminishing plasma concentrations [26]. Under steady-state conditions, the erythrocyte-to-plasma ratio can approach 25 1 [27]. Besides erythrocytes, tissues such as spleen and liver show a tendency for higher intracellular-to-extracellular ratios than that of potassium [28]. An exception to this is... 

Garcia-Ruiz, S., Moldovan, M., and Garcia Alonso, J.I. (2007) Large volume injection in ion chromatography separation of rubidium and strontium for on-line inductively coupled plasma mass spectrometry determination of strontium isotope ratios. J. Chromatogr. A, 1149 (2), 274-281. 

Oernemark, U.,Taylor, P. D. P, and De Bievre, P. (1997). Certification of the rubidium concentration in water materials for the international measurement evaluation programme (IMEP) using isotope dilution inductively coupled plasma mass spectrometry.J.Anal. At. Spectrom. 12(5), 567. 

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