PL-SAX

The lEC method can also be used for estimation of MMD of high and UHMM HA samples. Some HA samples, in the range of molar masses from 0.1 MDa to 5 MDa were successfully fractionated by Karlsson and Bergman by using an anion lEC chromatographic system [273]. A strongly anionic lEC column PL-SAX-4000 (Polymer Laboratories, Church Stretton, UK) was used... 

Figure 8. Ion-exchange HPLC of a mixture of proteins. Column, PL-SAX 100 nm 8 pm 50 X 4.6 mm eluant A, O.OI M Tris—HCI, pH 8.0 eluant B, 0.01 M Tris—HCl, 0.35 M NaCI, pH 8.0 gradient, linear 0—100% B over 20 min flow-rate, 1.0 ml/min detector, UV at 280 nm. Peaks, (1) myoglobin (2) con-albumin (3) ovalbumin (4) soyabean trypsin inhibitor.

Table 5-2. The relationship between pore size and specific ionic (m equivalents) or protein capacity (gmL column volume), as determined by frontal analysis for a range of strong anion exchangers based on a macroporous polystyrene matrix, PL-SAX.

Fig. 5-9. Plot of reciprocal column efficiency versus flow rate for the test probes. (A) Adenosine 5-monophosphate, (B) myoglobin, (C) ferritin using the strong anion exchanger, Pl SAX (Polymer Laboratories)...

The TEM (Fig. 44) and SAXS data clearly indicate that the structure is lamellar to the first order but modified by channels in the PI layers, leading to a PL pattern. However, Fredrickson s theoretical results indicate that in the SSL this structure is not the most favourable one [123]. In the WSL, similar PLs are to occur for equal weight fractions, even though lamellae are expected in that region [124]. A similar behaviour has been observed in the case of PI2PS homopolymer blends for the PL morphology [15]. 

SAXS is sensitive to variations in the electronic density in a material, and so provides information about the shape and size of clusters in micro PS. In contrast to the quantum wire structure proposed in early publications [Cal, Lei], the crystallites in micro PS are found to be almost spherical. There has been some evidence that the dimensions in the growth direction are somewhat smaller than those parallel to the surface [Fr2], The latter result, however, is still controversial because investigations by spectroscopic techniques indicate an opposite elongation [Mi4], A combination of grazing incidence diffraction (GID) and SAXS measurements on various freestanding micro PS films showed crystallite diameters from about 1.5 to 4 nm, depending on formation conditions. A good correlation between size reduction and blue shift of the PL peak position has been observed [Bi3],... 

Fig. 4.30 SAXS peak position, q, and inverse peak intensity as a function of inverse temperature for a PS-Pl-PS triblock (A/w = 120 kg mol-1,17wt% PS) in dibutyl phthalate (

Redissolve pellet in 100 pL H20 (see Note 6), and analyze deacylated [32P]-labeled lipids by HPLC using a 12.5-cm Whatman Partisphere SAX column. 

Absorption spectra were measured with a spectrophotometer MS-122. Photoluminescence (PL) was recorded with a fluorimeter Fluoromax-2 (A-ex = 325 nm). For SAXS measurements a device of the Institute of Silicate Chemistry of HAS, Russia (CuKa radiation with a Ni filter) was used. 

Very recently, (Bafna et al., 2003) developed a technique to determine the three-dimensional (3D) orientation of various hierarchical organic and inorganic structures in a PLS nanocomposite. They studied the effect of comjjatibilizer concentration on the orientation of various structures in PLS nanocomposites using 2D SAXS and 2D WAXD in three sample / camera orientations. 

Another illustrative example of the extra information that may be obtained via the combined use of SANS and SAXS, coupled with deuterium labeling, has been given by Hashimoto and co-workers [222, 223] in studies of the phase transitions of a triblock terpolymer, polyisoprene (Pl)-poly(deuterated styrene) (DPS)-poly(vinylmethyl ether) (PVME). The temperature dependence of the SAXS and SANS profiles exhibits intriguing features, as shown in Fig. 7.37, where the D-spacing estimated from the scattering vector, of the first-order maximum D = is plotted as a function of the inverse temperature for SAXS and... 

Fig. 7.37. (a) The temperature dependence of the domain spacing D calculated from the first-order scattering maxima for SAXS ( ) and SANS ( ) from a Pl-b-DPS-b-PVME triblock terpolymer, and schematic models for the domain structure at (b) T < 140 °C and (c) T > 140 °C. The spheres shown as open (o) and filled ( ) circles represent domains composed of PI and PVME blocks, respectively. (Reproduced with permission from [255]. Copyright 2002, Wiley-VCH, Weinheim.)... 

This work was supported by a POSTECH/BSRI special fond (1998) and the Korean Foundation of Science and Engineering ( 97-05-02-03-01-3). Synchrotron SAXS experiments at the PLS (3C2 beam line) were supported by the Ministry of Science and Technology (MOST) and Pohang Iron Steel Co. (POSCO). 

Synchrotron small-angle X-ray scattering (SAXS) measurements were carried out at 4C2 SAXS beamline in Pohang Light Source (PLS), which consisted of 2 GeV LINAC accelerator, storage ring, Si(lll) double crystal monochromator, ion chambers, and one-dimensional position sensitive detector with 2048 pixels. The... 

Experiments performed at Pohang Light Source (PLS) were supported in part by MOST and POSCO. We are very grateful to Y. J. Park for his assistance during SAXS experiments at PLS. K. Char is also very grateful to the LG-Yonam Foundation for its financial support during a sabbatical visit (1997 1998) to Cornell University. 

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