Baker-Williams method

An elegant variant of this procedure is known as the Baker-Williams method. In this method, the chromatographic column is also surrounded by a thermostated heating jacket which ensures that an adequate thermal gradient is maintained. The separation efficiency is enhanced by the simultaneous concentration and temperature gradients. 

Fig. 28. Distribution of the degree of polymerization of the 10th Baker-Williams fraction (middle fraction, Pw = 1500) of polystyrene sample Ti-Te-1, polymerized anionically in 1,2-dimethoxy-ethane at —48 °C PDC at 15 °C (O) and GPC, not corrected for spreading (strip method, A)...

In order to familiarize himself with macromolecules, he spent a postdoctoral year (1950-1951) with Professor A. Tiselius in Sweden. Together with Aim and Hagdahl they developed the method of gradient elution analysis. On his return to England, he showed how to apply temperature gradients to columns which, with solvent gradients, permit high polymer fractionation. These are called Baker-Williams columns. 

This paper describes the elimination of a systematic error in the Baker-Williams (BW) method, a combination of the BW and the gel permeation chromatography (GPC) methods for elimination of the effects of side reactions on the molecular weight distributions, and, finally, the application of these methods to some problems in the kinetics of anionic polymerization of styrene and methyl methacrylate. 

Within this contribution, we focus our attention on two methods, namely the Baker-Williams fractionation (BW) [40,41] and continuous polymer fractionation (CPF) [42]. The B W method leads to fractions with a very low nonuniformity and is deemed to be the most effective technique [43, 44]. CPF allows the isolation of fractions on the 100 g scale. 

Two patented large-scale techniques, based on liquid-liquid phase separation, are the continuous polymer fractionation (CPF) and the continuous spin fractionation (CSF)." The experimental setup of these two techniques will be presented in the next two sections (sections 2.04.2.1 and 2.04.2.2), which are followed by the description of two chromatographic methods, namely, the Baker-Williams fractionation (section 2.04.2.3) and the phase distribution chromatography (PDC) (section 2.04.2.4). 

Hall, C. J. Baker, J. Dahm, P. Freiburger, L. Gorder, G. Johnson, L. Junk, G. Williams, F. Safe Disposal Methods for Agricultural Pesticide Wastes, U.S.E.P.A. Report 600/2-81-074, NTIS Accession PB81 197584 (1981). 

Determination and Correction of a Systematic Experimental Error in the BW Method. For the characterization of narrow distributions, the direct measurement of Pn and Pw by osmosis and light scattering is not applicable. Even if the experimental error did not exceed 2%, then U = 0.05 and U = 0.03 could not be distinguished. The GPC method also has its limitations in this range. Therefore, at this time the best method for determining narrow distributions is precipitation chromatography as proposed by Baker and Williams (4) and elaborated on recently in our laboratory (5, 6, 7). 

Despite many years of investigation directed toward these and other related questions (Baker, 1990 Carlson, 1991 Boucot and Wilson, 1994 Copper and Gourvennec, 1996 Williams et al, 1996 Alvarez and Carlson, 1998), the answers remain elusive. This is due, in part, to the fact that the phylogenetic methods available to us do not ideally suit the full range of palaeontological data available in the form of both morphological variation and relative stratigraphic (temporal) position. Traditional methods of evolutionary systematics (sensu Simpson, 1961) often have relied heavily on... 

Baker and Williams suggested a firactionation method based on the precipitation and dissolution of polymers. The... 

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