Lithium Measurements

Figure 7 Lateral profiles of carbon and lithium measured by nuclear reaction analysis.

MRI lithium measurements are playing an important role in the development and understanding of the role of lithium in treating and preventing ASR. The spatial resolution and speed make this measurement technique very attractive for monitoring the removal of lithium from the pore solution during ASR and also in investigating how well various surface treatments will slow ASR. 

The major interest for Li+ analysis arises from the prophylactic and therapeutic action of Li+ in various affective disorders. Since the therapeutic action of Li+ is limited by adverse side effects above 2.0-2.5 mM Li+, monitoring of this analyte is indispensable. Reagents and methods (including ISE) for achieving high lithium over sodium selectivity and their use in blood lithium measurement have been reviewed <1996JPB899>. Enhanced lithium... 

The ISE systems of all three analysers measured lithium in undiluted serum as direct measurements. Automated system calibration and calculation of the results were in-built in all the instruments. The lithium measurement range of the Cobas Integra 700 ISE module was from 0.10 mmol/l up to 4.00 mmol/l. According to the manufacturer s specifications the linear measurement range of the Kone Microlyte 6 ISE analyser was from 0.20 mmol/l to 4.00 mmol/l and for the Chiron 654 ISE from 0.20 mmol/l to 5.00 mmol/l. 

Figure 15.12 Diffraction diagram of lithium measured at high pressures and low temperatures. The upper diagram shows the raw data after integration of a 2D imaging plate pattern, the lower intensities result after back ground correction. The background is attributed to the Compton scattering of the diamonds.

Information appears to be limited to the reports cited, but the interaction would seem to be established. Avoid concurrent use whenever possible, but if this is not workable then the effects should be closely monitored. Serum-lithium measurements may be unreliable because symptoms of toxicity can occur even though the levels remain within the normally accepted therapeutic range. 

In order to check the ability of the FSA anion based phosphonium RTILs as lithium battery electrolytes, the electrochemical behavior of lithium in the FSA anion based phosphonium RTILs has been investigated by using a cyclic voltammetry technique. Figure 15 displays the cyclic voltamograms of lithium measured... 

One procedure makes use of a box on whose silk screen bottom powdered desiccant has been placed, usually lithium chloride. The box is positioned 1-2 mm above the surface, and the rate of gain in weight is measured for the film-free and the film-covered surface. The rate of water uptake is reported as u = m/fA, or in g/sec cm. This is taken to be proportional to - Cd)/R, where Ch, and Cd are the concentrations of water vapor in equilibrium with water and with the desiccant, respectively, and R is the diffusional resistance across the gap between the surface and the screen. Qualitatively, R can be regarded as actually being the sum of a series of resistances corresponding to the various diffusion gradients present ... 

McKillop and associates have examined the electrophoretic separation of alkylpyridines by CZE. Separations were carried out using either 50-pm or 75-pm inner diameter capillaries, with a total length of 57 cm and a length of 50 cm from the point of injection to the detector. The run buffer was a pH 2.5 lithium phosphate buffer. Separations were achieved using an applied voltage of 15 kV. The electroosmotic flow velocity, as measured using a neutral marker, was found to be 6.398 X 10 cm s k The diffusion coefficient,... 

Reactions of the Hydroxyl Group. The hydroxyl proton of hydroxybenzaldehydes is acidic and reacts with alkahes to form salts. The lithium, sodium, potassium, and copper salts of sahcylaldehyde exist as chelates. The cobalt salt is the most simple oxygen-carrying synthetic chelate compound (33). The stabiUty constants of numerous sahcylaldehyde—metal ion coordination compounds have been measured (34). Both sahcylaldehyde and 4-hydroxybenzaldehyde are readily converted to the corresponding anisaldehyde by reaction with a methyl hahde, methyl sulfate (35—37), or methyl carbonate (38). The reaction shown produces -anisaldehyde [123-11-5] in 93.3% yield. Other ethers can also be made by the use of the appropriate reagent. 

Oil Fields. Oil field waters in the United States containing lithium have been identified in 10 states. The greatest concentrations are in waters from the Smackover formation of southern Arkansas and eastern Texas. Concentrations from this formation have been measured from 300—600 ppm in waters originating at a 2500—3300 m depth. Recovery of lithium from this resource would only be commercially feasible if a selective extraction technique could be developed. Lithium as a by-product of the recovery of petroleum (qv), bromine (qv), or other chemicals remains to be exploited (12). 

Demonstrated reserve quantities are estabUshed by measurements including drillings surface sampling, etc. Inferred reserves are those derived from geological survey information, not by measurement of the extent of the particular reserve. Not included herein are identified marginal and speculative resources, such as the oil-field and geothermal brines and lithium-hearing clays. These latter reserves are speculative as to extent, not existence. Total undiscovered clays in the western United States are speculatively estimated at 15 x 10 t lithium (16). More detailed Hsts of reserves are also available (15,17). 

The double titration method, which involves the use of ben2ylchloride, 1,2-dibromoethane, or aUyl bromide, determines carbon-bound lithium indirectly (101,102). One sample of the //-butyUithium is hydroly2ed directly, and the resulting alkalinity is determined. A second sample is treated with ben2ylchloride and is then hydroly2ed and titrated with acid. The second value (free base) is subtracted from the first (total base) to give a measure of the actual carbon-bound lithium present (active base). 

The oxidimetric method, which involves the use of soUd vanadium pentoxide as oxidant (103). The vanadium is reduced quantitatively by butyUithium and is determined potentiometricaUy by titration with standard sulfatoceric acid [17106-39-7]. This method gives a direct measure of the actual carbon-bound lithium present when compared to the total titrated alkalinity. 

Refractive Index. The effect of mol wt (1400-4000) on the refractive index (RI) increment of PPG in ben2ene has been measured (167). The RI increments of polyglycols containing aUphatic ether moieties are negative drj/dc (mL/g) = —0.055. A plot of RI vs 1/Af is linear and approaches the value for PO itself (109). The RI, density, and viscosity of PPG—salt complexes, which maybe useful as polymer electrolytes in batteries and fuel cells have been measured (168). The variation of RI with temperature and salt concentration was measured for complexes formed with PPG and some sodium and lithium salts. Generally, the RI decreases with temperature, with the rate of change increasing as the concentration increases. 

Individual polyethers exhibit varying specificities for cations. Some polyethers have found appHcation as components in ion-selective electrodes for use in clinical medicine or in laboratory studies involving transport studies or measurement of transmembrane electrical potential (4). The methyl ester of monensin [28636-21 -7] i2ls been incorporated into a membrane sHde assembly used for the assay of semm sodium (see Biosensors) (5). Studies directed toward the design of a lithium selective electrode resulted in the synthesis of a derivative of monensin lactone that is highly specific for lithium (6). 

Ion Selective Electrodes Technique. Ion selective (ISE) methods, based on a direct potentiometric technique (7) (see Electroanalytical techniques), are routinely used in clinical chemistry to measure pH, sodium, potassium, carbon dioxide, calcium, lithium, and chloride levels in biological fluids. 

Figure 9.20 shows the setup for a symmetric plate impact test. The projectile here has a facing plate of ceramic and is backed with a low-density foam, for support of the ceramic during launch. The facing plate of the target is also made of ceramic. The lithium fluoride slab, which backs the target sample, serves as a window for the laser velocity interferometer (VISAR) that measures the time-resolved particle velocity at the sample/window interface. 

There are many ways to eharaeterize the strueture and properties of carbonaceous materials. Among these methods, powder X-ray diffraetion, small angle X-ray scattering, the BET surfaee area measurement, and the CHN test are most useful and are deseribed briefly here. To study lithium insertion in carbonaeeous materials, the eleetroehemieal lithium/earbon eoin eell is the most eonvenient test vehicle. 

Fig. 22. The capacity of the one volt plateau measured during the second cycle of several series of samples versus the H/C atomic ratio in the samples. The solid line suggests that each lithium atom binds quasi-reversibly to one hydrogen atom.

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