Solid and solution phase analysis

Molecular Geometry and Stability Solid and Solution Phase Analysis of A/,AT-disalicylaldehyde-1,3-propanediimine nickel(ll)... 

MOLECULAR GEOMETRY AND STABILITY SOLID AND SOLUTION PHASE ANALYSIS... 

The total salt concentration was 0.100 (to.010) N, known to three significant figures. At the high end of the isotherm, the starting solution contained only the ingoing cation at the low end, the solution contained both of the exchanging cations. The equilibrations were carried out for a minimum of three days in a New Brunswick Scientific Company AQUATHERM Water Bath Shaker at 5°, 25°, and 50°C, with temperature control to i0.5°C. Prior to analysis of the equilibrium solutions, the solid and solution phases were rapidly separated by filtration through a Millipore filter immediately after removal from the constant temperature bath. Lead and sodium analyses of the filtrate were obtained by atomic absorption spectroscopy. The cadmium analyses of the filtrate were obtained by plasma emission spectroscopy. These analyses showed that two Na+ ions entered the solution for every Cd2+ or Pb2+ that left ( 2%). 

DB Kassel. A fully automated mass spectrometry based system for the rapid analysis and purification of combinatorial libraries. Solid and Solution Phase Combinatorial Synthesis, New Orleans, 1997. 

Results comparable to those shown in Figure 1 can readily be achieved with most crude mixtures containing synthetic or naturally occurring peptides, using similar RPC strategies. The resolution of synthetic peptides prepared by solid- or solution-phase chemical methods is now so routine by analytical and preparative RPC methods that an April 2000 CD-ROM database search of relevant scientific journals revealed that over 2500 publications arise each year on the use of RPC for the purification or analysis of peptides as part of the scientific literature related to peptide chemistry and its application in various fields of the biomedical or biological science and in biotechnological applications related to the food, environmental, and pharmaceutical industries. 

The heat capacities of series of ammonium bromides ([(Ci)2C3HOC2N]Br, [(Cj)2C4HOC2N]Br, and [(Q)2QHOC2N]Br) were measured for the solid and liquid phase, and the difference in the solute heat capacity between the liquid and solid phase at the melting temperature, j has been determined by the DSC analysis [79]. Negative values of were observed for these... 

The problem of separating solid and liquid phases either before or after taking a sample drop or two of the test solution frequently arises in spot test analysis. When there is a comparatively large volume of liquid and the solid matter is required, centrifugation in a micro centrifuge tube (Fig. 11.34) may be employed. Alternatively, a micro sintered glass filter tube (Fig. 11.49), placed in a test-tube... 

The basic information in the study of sorption processes is the quantity of substances on the interfaces. In order to measure the sorbed quantity accurately, very sensitive analytical methods have to be applied because the typical amount of particles (atoms, ions, and molecules) on the interfaces is about I0-5 mol/m2. In the case of monolayer sorption, the sorbed quantity is within this range. As the sorbed quantity is defined as the difference between quantities of a given substance in the solution and/or in the solid before and after sorption processes (surface excess concentration, Chapter 1, Section 1.3.1), all methods suitable for the analysis of solid and liquid phases can be applied here, too. These methods have been discussed in Sections 4.1 and 4.2. In addition, radioisotopic tracer method can also be applied for the accurate measurement of the sorbed quantities. On the basis of the radiation properties of the available isotopes, gamma and beta spectroscopy can be used as an analytical method. Alpha spectroscopy may also be used, if needed however, it necessitates more complicated techniques and sample preparation due to the significant absorption of alpha radiation. The sensitivity of radioisotopic labeling depends on the half-life of the isotopes. With isotopes having medium half-time (days-years), 10 14-10-10 mol can be measured easily. 

Knowing the thermal stability of clathrates permits the prediction of experimental conditions for polymerization (8). A detailed analysis of this problem requires the examination of all the involved phases, particularly the solid and liquid phases. Equations for phase equilibria were derived from within the framework of the regular solution theory they contain an interaction parameter W, (whose value is always positive or zero for ideal solutions), which measures the tendency of host and guest to segregate in the liquid phase. The melting or decomposition point is very sensitive to the value of W, especially when it exceeds 2 RT, i.e. when a miscibility gap is observed in the liquid phase. For this reason the PHTP-hydrocarbon clathrates melt congruently between 115 and 180 C, whereas the urea-hydrocarbon... 

The distribution of the solute between the solid and liquid phase can be detei-mined not only from depletion of solution, but also by analysis of the adsorbent separated from the solution. The latter approach is not too popular because of serious experimental difficulties. Namely, such measurements are severely affected by the liquid trapped in pores and cracks of the solid and intergrain space. Washing procedures aimed at removal of residual liquid usually induce partial release of pre-sorbed substances. 

Structural analysis of linear polymers molecularly dissolved in a suitable solvent using and solution phase NMR spectroscopy is long established [87-89]. Not surprisingly therefore when a linear soluble polymer is used as a support in solid phase synthesis and solution phase NMR spectroscopy can be a powerful tool in following the chemical synthesis on the support [90]. Figure 15.3.58, for example, shows a series of H NMR spectra of dissolved linear polymer samples taken at various stages in the solid phase synthesis of oligoethers on soluble polystyrene [91]. The various chemical steps Fig. 15.3.59 are clearly demonstrated. 

C. Equilibrium between Solid and Liquid Phases only. I. The Components are Completely Miscible in the Liquid State. a) The pure components only occur as solid phases. Polymorphism of components. Determination of the equilibrium curve. Example, b) Compounds are formed with a congruent meltings point. The indifferent point. Determination of the composition of a compound by thermal analysis. Examples, (c) Compounds are formed with an %ncongruent melting-point. Determination of the composition of the coinpound by thermal analysis. Example. (d) Solid solutions or " mixed crystals are formed, i) The two components can form an unbroken series of solid solutions. Examples. Melting-point curve. Example. Fractional crystallisation of solid solutions, h) The two components do not form a continuous series of solid solutions. Examples. Changes in solid solutions with the temperature. II. The Components are not Completely Miscible in the Liquid State. Suspended transformation. 

The cell theory plus fluid phase equation of state has been extensively applied by Cottin and Monson [101,108] to all types of solid-fluid phase behavior in hard-sphere mixtures. This approach seems to give the best overall quantitative agreement with the computer simulation results. Cottin and Monson [225] have also used this approach to make an analysis of the relative importance of departures from ideal solution behavior in the solid and fluid phases of hard-sphere mixtures. They showed that for size ratios between 1.0 and 0.7 the solid phase nonideality is much more important and that using the ideal solution approximation in the fluid phase does not change the calculated phase diagrams significantly. 

Unless solubility data for specific industrial substances are required, both the solute and solvent should be of the highest purity possible. The solute partieles should be reasonably small to facilitate rapid dissolution, but not too small that the excess particles will not settle readily in the saturated solution. Settling is generally desirable to allow solid and liquid phase samples to be taken, after equilibration, for separate analysis. In practice, a close-sieved crystal fraction in the 100-300 pm size range is generally suitable for most purposes. 

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