Chromatography inversed size-exclusion

Goto, M McCoy, BJ, Inverse Size-Exclusion Chromatography for Distributed Pore and Solute Sizes, Chemical Engineering Science 55, 723, 2000. 

A second project [10] was based on the production of Pd nanocluster inside poly-methacrylic acid (8%mol)-A,iV-di-methylacrylamide (88 % mol)-A, A -methylenebisacrylamide (4% mol). ISEC (Inverse Size Exclusion Chromatography) analysis of the resin in water in terms of cylindrical pores [7]... 

Al-Bokari, M., Cherrak, D., Guiochon, G. (2002). Determination of the porosities of monolithic columns by inverse size-exclusion chromatography. J. Chromatogr. A 975, 275-284. 

Eor means of determination and quantification of the material porosity, different methods like mercury intrusion porosity, nitrogen gas adsorption, or inverse-size exclusion chromatography (ISEC) have been established and are nowadays routinely employed for that purpose. As an alternative to these well-known methods, a new approach based on near-infrared spectroscopy (NIR) for the characterization of monoliths is introduced in this chapter. 

The major problem in inversed size-exclusion chromatography is the arbitrary judgment that a pore must be much larger, in order to allow a polymeric coil to enter it. On the other hand, large and flexible cods of polystyrene have been reported to penetrate into narrower pores, due to the change of their spherical conformation and reptation-type movements... 

The pore size and distribution are defined by nitrogen adsorption (BET) or mercury porosimetry. In chromatographic terms, inverse size-exclusion chromatography (SEC) is particularly suitable, because only those pores are measured that are chromatographically available. 

Figure 5.4 Inverse size-exclusion chromatography from two different poiystyrene phases. Source J. Maier-Rosenkranz, PhD thesis, Tubingen, 1992.

Journal of Applied Polymer Science 61, No.8, 22nd Aug.1996, p.1325-31 DIRECT DETERMINATION OF THE RESIDUAL ACRYLAMIDE CONCENTRATION IN INVERSE (WATER-IN-OIL) POLYACRYLAMIDE EMULSIONS FOLLOWING PHASE INVERSION SIZE EXCLUSION CHROMATOGRAPHY USING A MICELLAR MOBILE PHASE Hemandez-Barajas J Hunkeler D J Petro M Vanderbilt University... 

Lubda, D., Lindner, W Quaglia, M., du Fresne von Hohenesche, C., Unger, K K., 2005. Comprehensive pore stmcture characterization of silica monohths with controlled mesopore size and macropore size by nitrogen sorption, mercury porosimetry, transmission electron microscopy and inverse size exclusion chromatography. J. Chromatography A 1083 14-22. 

The volume fractions of both micropores (Sp) and voids (inter-microglobule porosity, e ) represent the total porosity (8t). This value indicates a percentage of pores in the monolith. The pore size distribution can be calculated from inverse size exclusion chromatography (ISEC) data or from mercury intrusion. " Together, these two values translate into a total pore volume Vp, expressed in mlg". ... 

While polydisperse model systems can nicely be resolved, the reconstruction of a broad and skewed molar mass distribution is only possible within certain limits. At this point, experimental techniques in which only a nonexponential time signal or some other integral quantity is measured and the underlying distribution is obtained from e.g. an inverse Laplace transform are inferior to fractionating techniques, like size exclusion chromatography or the field-flow fractionation techniques. The latter suffer, however, from other problems, like calibration or column-solute interaction. 

Gel-type, microporous, resins must swell to expose their catalytically active sites, whereas macroreticular resins have a permanent pore structure (inside these pores, catalytically active sites reside). Pores of the macroreticular resins can be described acceptably in terms of the conventional cylindrical pore model (pore diameter and volume). Pore structure, size, pore volume, and so on have been studied intensively in recent years. Examples of analytical techniques include X-ray microprobe analysis, ESR spectroscopy, NMR, and inverse steric exclusion chromatography (ISEC) the latter yields the best quantitative assessment of the nanomorphology of swollen resins. 

Figure 4.6-6 Arrhenius plot of the inverse average degree of polymerization, determined by either viscosimetry or size-exclusion chromatography for polyethylenes produced at 2000 bar and various temperatures T, the initiation and thus termination rates are very low in these experiments [37,38].h...

The rightmost term on the right side of the equation can be seen as the selectivity in size-exclusion chromatography. It is the inverse of the slope of the dimensionless form of the calibration curve multiplied by the fraction of the column occupied by pores. It should be maximized by selecting the best pore size and pore size distribution for the molecular-weight range of the analyte. 

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