The behavior of the lithium (Li) ion in normal human erythrocytes has been studied by 7Li NMR. The uptake of Li into the cells was followed as a function of solution conditions, temperature, hematocrit, and blood age using dysprosium tripolyphosphate shift reagent. Under our conditions the uptake of Li increases with increasing hematocrit and blood age. For packed cells the extracellular 7Li spin-lattice relaxation time was only slightly longer than the intracellular relaxation time. Thus, T1 may not be useful for separate observation of intra- and extracellular Li in vivo. The intra- and extracellular T2s were substantially shorter than the corresponding T1s. Also, the intracellular T2 was considerably shorter than that for the extracellular compartment, suggesting that T2 may provide a noninvasive handle for observation of intracellular Li. Nuclear Overhauser enhancements could be observed for both extra- and intracellular 7Li, confirming that dipolar coupling to 1H is a contributing relaxation mechanism. The 7Li NMR visibility was essentially 100% at high Li concentrations, decreasing to about 84% at 1 mM Li. Based on time course studies of the invisibility, and a comparison of NMR and inductively coupled plasma results, it appears that the invisibility of the intra- and extracellular compartments for packed cells is the same. Although a 23Na double-quantum signal could be observed for red blood cells, no double-quantum signal was observed for 7Li.

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A previously described synthetic method was modified to improve the porosity of the alumina product. The compound (Et2AlNH2)3 was prepared from ammonia and triethylaluminum (Et3Al) in toluene solvent. Addition of acetone to form a solution of ethylaluminoxane (EtAlO) and acetonine (2,2,4,4,6-pentamethyl-2,3,4,5-tetrahydropyrimidine) was followed by addition of two equivalents of water to give an alumina precursor. Alumina precursors also were prepared by the direct hydrolysis of (Et2AlNH2)3. Powder X-ray diffraction, 27Al MAS NMR, and N2 adsorption/desorption isotherms were used to analyze the aluminas after calcination of the precipitates. The aluminas exhibited high pore volume and surface area, and they were amorphous after calcination at 500 °C. One alumina showed a significant fraction of pentacoordinate aluminum after heating to 300 °C in air or 500 °C in steam atmosphere. The products crystallized as α-Al2O3 at the low temperature of 1000 °C, which reduces their applicability for catalysts. Synthesis variables and their effects on alumina properties are discussed.

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