Selection of a Chromatographic Solvent.

Abstract

Two complementary quantitative indexes of the resolving power of a chromatographic system, the ratios of the chemical potentials of transfer of related compounds and the ratio of the cross-sectional areas

Tools and techniques for solvent selection: green solvent selection guides

“…Reaction specific solvent selection guides are now available [87][88][89], which rank a set of solvents according to the observed performance (not greenness). The requirement of the solvent in chromatography as the mobile phase is so obvious in its importance that solvent guides for this application predate all other tools [90,91], and has now been revived as a research topic [92,93]. Technological requirements can be balanced against solvent greenness through general purpose solvent selection guides, and alternative methods of computational solvent optimisation [65,94].…”

Tissue residue and comparative metabolism studies on tiazuril in the chicken, rat, dog, and monkey

“…Reference samples of T, T-SO, and T-S02, each N-methylated, were spotted on opposite sides of the plate, or developed as separate controls on a second TLC plate. The TLC plate was then developed by the "multiple pass" ascending technique of Thoma (1965) in a benzene-acetic acid (95:5) solvent system. Reference compounds were detected by their absorption under UV light (254 nm) and the corresponding sample zones excised from the silica gel adsorbent.…”

Guidelines for selection of chromatographic conditions

“…The locale of maximum resolution can be predicted if the separation between spot centers as well as the extent of zone spreading can be quantitatively related to R,. The key relationships useful for these predictions were derived from our earlier studies on the thermodynamic behavior of polar chromatographic systems (5) and the work of Giddings and Keller (6) relating spot size to the diffusion characteristics. We discovered that for polar solutes and solvents, the ratio of the chemical potentials of transfer of structurally related compounds was constant and independent of solvent proportions within experimental error (5,7).…”

“…The key relationships useful for these predictions were derived from our earlier studies on the thermodynamic behavior of polar chromatographic systems (5) and the work of Giddings and Keller (6) relating spot size to the diffusion characteristics. We discovered that for polar solutes and solvents, the ratio of the chemical potentials of transfer of structurally related compounds was constant and independent of solvent proportions within experimental error (5,7). Giddings and Keller have shown that spots are normally elliptical, and their size depends upon several dispersive 'actors and the sensitivity of the detection method (2).…”

“…It must be remembered throughout the following discussion that all dimensions are normalized to unit support length and that their absolute values will be proportional to support length; thus their relative values are reported as dimensionless units comparable to /?zand AR,. MODELS AR, as a Function of RIn preceding articles (5,7) it has been amply demonstrated that Martin's relationship (10) (Equation 1) is extremely useful for describing chromatography of polar solutes with polar solvents on paper. log« R -1 (1) It is also known that for a given set of solvent components, both R, and AR, can be regulated within limits by changing solvent proportions.…”