Characterization of Solutions

In activity studies in multicomponent systems, G. N. Lewis and M. Randall found in 1923 that in the case of dilute solutions, when a foreign electrolyte is added, the activity change of the substance studied depends only on the concentration and valence type of the substance added, not on its identity. For a quantitative characterization of solutions, they introduced the concept of ionic strength / of a solution (units mol/L),... 

Coleman ML, Eggenkamp HGM, Aranyossy JF (2001) Chlorine stable isotope characterization of solute transport in mudrocks, ANDRA. Actes des Jounces Scientifiques EDP Sciences, France, p 155-175 Curie I (1921) Sur le poids atomique du chloe dans quelques mineraux. CR Acad Sci (Paris) 172 1025-1028 Deruelle B, Dreibus G, Jambon A (1992) Iodine abundances in oceanic basalts implications for Earth dynamics. Earth Planet Sci Lett 108 217-227... 

One of the best characterized of solution reactions is the hydrolysis of simple acetals and ketals which almost certainly utilizes the A-l reaction path. The mechanism is as follows (Kreevoy and Taft, 1955 O Gorman and Lucas, 1950) ... 

Hence, stationary phases can be characterized very quickly by measuring the retention indices of the five probe solutes. On the other hand, the characterization of solutes is not so easy, for a combination of reasons. In the first place, a set of five equations with five unknowns has to be solved. In the second place, the retention indices of the solute need to be obtained on five different stationary phases with known Rohrschneider constants, as well as on squalane. Hence, six different columns are needed. Moreover, in order to obtain reproducible data, very careful experimentation is required. It is especially difficult to maintain a squalane column. In this light, the choice of squalane as a reference phase has been unfortunate. Therefore, the Rohschneider scheme has become extremely popular for the characterization of stationary phases, and not for the characterization of both phases and solutes, allowing the prediction of retention indices through equation 2.5. 

Mamantov G., Osteryoung R. A., Acid-Base Dependent Redox Chemistry in Molten Chloroaluminates in Characterization of Solutes in Nonaqueous Solvents, G. Mamantov, ed., Plenum Press, New York, 1978, p. 223. 

One should not adhere to the mistaken notion that the analysis of subsection (a) can be used in the upper range of xA values and that the analysis of subsection (b) for the same solution can then be used in the lower range. The two approaches are based on different standard states (i.e. P versus P, as discussed earlier) and therefore are not interchangeable or interrelated. Further, one must stay with one scheme or the other to obtain internally consistent results. It is just more convenient to apply methodology (b) if one is interested primarily in the thermodynamic characterization of solutes in dilute solution, and methodology (a) if one wishes to analyze the properties of solvents. This discussion again points to the fact (see also subsection (e) below) that it is only the differences in the chemical potential themselves that are unique in value all other quantities must be determined self-consistently. 

Ill] A. I. Popov The Use of Alkali Metal Nuclear Magnetic Resonance in the Study of Solvation and Complexation of Alkali Metal Ions, in J. F. Coetzee and C. D. Ritchie (eds.) Solute-Solvent Interactions, Dekker, New York, London, 1976, Vol. 2, p. 271ff. A. I. Popov Alkali Metal, Mag-nesium-25, and Silver-109 NMR Studies of Complex Compounds in Nonaqueous Solvents, in G. Mamantov (ed.) Characterization of Solutes in Non-Aqueous Solvents, Plenum Publ. Corp., New York, 1978. [111a] P. Laszlo Kernresonanzspektroskopie mit Natrium-23, Angew. Chem. 90, 271 (1978) Angew. Chem. Int. Ed. Engl. 17, 254 (1978). [112] N. A. Matwiyoff, P. E. Darley, and W. 

Good summaries of accepted experimental techniques can be found in the references that are cited for individual radionuclides in the sections below. Nitsche (1991) provides a useful general summary of the principles and techniques of solubility studies. A large number of techniques have been used to characterize the aqueous speciation of radionuclides. These include poten-tiometric, optical absorbance, and vibrational spectroscopy. Silva and Nitsche (1995) summarize the use of conventional optical absorption and laser-based photothermal spectroscopy for detection and characterization of solution species and provide an extensive citation list. A recent review of the uses of Raman and infrared spectroscopy to distinguish various uranyl hydroxy complexes is given by Runde et al. (2002b). 

Cserhati, T. Forgacs, E. Structure-retention relationships and physicochemical characterization of solutes in thin layer chromatography. J. AOAC Int. 1998, 81, 1105-1107. 

DH Evans, S Nelsen. In Characterization of Solutes in Non-Aqueous Solvents (G Mamantov, ed.). New York Plenum Press, 1978, p 131. 

V NMR spectroscopy is a particularly useful method for solution studies of vanadium(V) complexes. Several correlations of the shielding in vanadium(V) complexes have been reported and have been used as empirical guides to the coordination number of the vanadium.57-64 Application of these correlations should, however, be used cautiously. 170 NMR spectroscopy65 and extended X-ray absorption fine structure (EXAFS) spectroscopy have been used for the characterization of solution complexes.66 Methods including potentiometry, X-ray diffraction, and UV-visible and IR spectroscopic techniques are also widely used in the characterization of the properties of vanadium complexes. Other methods for the characterization of low-level (sub-microgram) vanadium complexes have been described 67,68... 

T.Eirola Sobolev Characterization of solutions of dilation equations. SIAM J Math Anal 23(4), ppl015-1030, 1992... 

Guenther M, Gerlach G, Gotten C, Kuckling D, Sorber J, Arndt K-F (2008) Hydrogel-based sensor for a rheochemical characterization of solutions. Sens Actuat B 132(2) 471 76 Hannon ME, Kuckling D, Frank GW (2003) Photo-cross-linkable PNIPAAm copolymers. 

Singh, T.B. et al.. Fabrication and characterization of solution-processed methanof-... 

The formation of polyoxometallates is a characteristic of V, Mo, W (see Section 22.7) and, to a lesser extent, Nb, Ta and Cr. Characterization of solution species is aided by and V NMR spectroscopies, and solid state structures for a range of salts are known. The structural chemistry of V2O5 and vanadates is complicated and only a brief survey... 

Yang, S. and Khaledi, M.G, Chemical selectivity in micellar electrokinetic chromatography characterization of solute-miceUe interactions for classification of surfactants. Anal. Chem., 61, 499, 1995. 

Depending on the type of solvent and the nature of the interaction to be studied, it may be necessary to utilize different experimental methods for the investigation of the solvent effect. In fact, the method of application of the same technique may vary considerably according to the properties of the system in question. This is the explanation of the extremely diverse nature of the investigations in this field, and why it is so difficult (and perhaps impossible) to develop a general method or common procedure for the characterization of solution systems. 

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