Review of Methods

Regarding GC methodology, four aspects must be examined  

After having dissolved the substance containing the RS to be looked for in an appropriate solvent, it is possible to directly inject into the system 100% of an aliquot of the solution (if packed columns are used) or partially through a split system (if capillary, narrow-bore and wide-bore columns are used). It is simple, accurate and repeatable (with an internal standard). The main drawback is that samples very often contain non-volatile substances which are retained by the column, leading rapidly to a loss of efficiency and a dramatic decrease in sensitivity. In the current literature dealing with the RS, the direct injection process is less frequently used. Nevertheless, publications have appeared until recently using split/ splitless injection.  

The solubilized or suspended sample in an appropriate vehicle is heated at a defined temperature in a tightly closed vial until thermodynamic equilibrium is reached between the hquid phase and the gas phase. A known aliquot is then transferred either wifli flie aid of a syringe or by an automatic transfer system onto the colutrm. The main advantage is that only volatile products including solvents are injected into the colunrn greatly improving its lifetime. The sensitivity is good and flic system is easily automated. 

The main drawback is flic existence of matrix effects and the possible non- ideahty of the solvents mixture. These imply that ideally one should determine the cahbration curve by adding standard solutions of the solvents of interest to the sample matrix, fiee of solvents. Because it is very difficult to obtain such a sample matrix, the classical standard addition method is recommended. It consists of adding to the sample matrix to be analyzed a known amount of the solvents to be determined. This method requires two analyses for the final calculation but the main advantage is that the matrix effect is overcome. The linearity of the response has, of course, to be demonstrated before the use of the simplified version mentioned above. Nevertheless, if based on a sound validation, external calibration can be used.  

The nature of the solvent used to prepare the solution (e.g., water, dimethylformamide, dimethylacetamide, l,3-dimethyl-2-imidazohdinone (DM1)), equilibration temperature, the ratio between the gas phase and the liquid phase and the possible need to promote a salting out effect by adding mineral salts are the parameters, amongst ofli-ers, which should be investigated and optimized to improve the sensitivity (LOD, LCXJ) of the method.  

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A review of methods for predicting properties of solids and surfaces is... 

Reviews of antiseptics for skin and wound cleansers (341), a review of methods for testing antiseptics (329), and an overaH review of antiseptics and their testing methods (342) ate avaHable. 

One concerned with the measurement of gas-hquid interfacial tension should consult the useful reviews of methods prepared by Harkius [in Chap. 9 of Weissberger, Techniques of Organic Chemstry, 2d ed., vol. I, part 2, Interscience, New York, 1949), Schwartz and coauthors [Suiface Active Agents, vol. I, Interscience, New York, 1949, pp. 263-271 Suiface Active Agents and Detergents, vol. 2, Interscience, New York, 1958, pp. 389—391, 417—418], and by Adamson [Physical Chemistry of Suifaces, Interscience, New York, I960]. 

Tombach, 1., "A Critical Review of Methods for Determining Visual Range in Pristine and Near-Pristine Areas," Proceedings of the Annual Meeting of the Air Pollution Control Association, Pittsburgh, 1978. 

Benson, R.S., A Review of Methods for Assessing Loss Coefficients in Radial Gas Turbines, International Journal of Mechanical Sciences, 12 (1970), pp. 905-932. 

Systems also vary in the extent of the metastable zone width, the point after whieh spontaneous nueleation is said to oeeur. Within the metastable zone, however, seed erystals may grow. Metastable zone width is therefore an important faetor in assessing the propensity of a system to erystallize and in deeiding the appropriate erystallization teehnique. Kim and Mersmann (2001) provide a review of methods for estimation for metastable zone widths both unseeded and seeded systems. 

Pritchard, D. K. 1989. A review of methods for predicting blast damage from vapor cloud explosions. 7. Loss Prev. Proc. Ind. 2(4) 187-193. 

The purpose of the present chapter is to provide an up-to-date review of methods which may be applied for the synthesis of both achiral and chiral (racemic and optically active) sulphoxides as well as their derivatives. Since the synthesis of optically active sulphoxides is based on many special procedures, it was found necessary to separate the syntheses of achiral and racemic sulphoxides from those of optically active ones. 

For a discussion of these rules, as well as for a review of methods for establishing configurations of chiral compounds not containing chiral atoms, see Krow, G. Top. Stereochem., 1970, 5, 31. 

For a review of methods of synthesis of aldehydes, ketones and carboxylic acids by coupling reactions, see Martin, S.F. Synthesis, 1979, 633. 

For reviews of methods for preparing alkynes, see Friedrich, K. in Patai Rappoport The Ghemistry of Functional Groups, Supplement G, pt. 2 Wiley NY, 1983, p. 1376 Ben-Efraim, D.A. in Patai The Chemistry of the Carbon-Carbon Triple Bond, pt. 2 Wiley NY, 1978, p. 755. For a comparative study of various methods, see Mesnard, D. Bemadou, F Miginiac, L. J. Ghem. Res. (S), 1981, 270, and other papers in this series. 

Van Kleef, E., Van Trijp, H.C.M., and Luning, R, Consnmer research in the early stages of new prodnct development a critical review of methods and techniqnes. Food Qual. Pref., 16, 181, 2005. 

R. Turner 1993, (Gradient coil design a review of methods), Magn. Reson. Imag. 11, 903-920. 

There have been a number of very helpful reviews of aspects of VS in the past few years. These have focused on either specific methods, or on the field as a whole. Cramer has provided an interesting review of methods of lead-hopping, concentrating on technologies applicable to find scaffolds very different from... 

This paper is a review of methods for estimating releases of chemicals into the environment in the course of extraction of raw materials, manufacturing, use, storage, transportation, and disposal, as well as by accidents or natural processes. It discusses source types, forms of substances released (solids, liquids, and gases), receiving media (air, water, soil), time pattern of release (continuous versus intermittent, cyclic versus random), and geographic patterns of release (point, line, area, and volume sources). 

Tavakoli, A., Sohrabi, M. and Kargari, A. (2007) A review of methods for synthesis of nanostructured metals with emphasis on iron compounds. Chemical Papers,... 

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