Fractograms polystyrene sample

In a study from our laboratory published in 1985, thermal FFF was applied to a polystyrene sample whose nominal molecular mass was 20.6 million [36]. A fractogram of this polymer obtained using tetrahydrofuran (THF) as a... 

Figure 8.9 Fractogram showing the distribution of components on both a molecular mass (M) and a retention volume (7 ) scale for a nominal 20.6 million molecular mass polystyrene sample. For this run, AT=8°C. Reprinted with permission from Macromolecules 18, 1272 1985...

Figure 8.11 Fractogram of polystyrene samples of indicated molecular mass using programmed field thermal FFF. The change in the hot wall temperature over the course of the run beginning at 87°C (corresponding to AT= 70°C) is shown by the continuous line. Reprinted with permission from Anal Chem. 48, 1587 1976 American Chemical Society.

Fig. 1 provides a comparison of fractograms for the 0.357 p,m polystyrene injected as a narrow pulse (Fig. 1 a) and injected at 10 ml dilution (Fig. lb) by the conventional SdFFF concentration procedure described previously. Fig. lb shows that the eluted peak from the diluted sample emerges intact and without serious degradation, compared to the peak of Fig. la, despite the fact that the sample volume (10 ml) is over twice the channel volume (4.5 ml). The same concentration procedure was also successfully applied to the separation of the two polystyrene samples initially mixed together in a volume of 10 ml, as well as to the concentration of the colloidal particles contained in natural water samples collected from the Colorado, Green, and Price rivers in eastern Utah (U.S.A.). 

Narrow particle fractions approaching a monodisperse distribution are particularly easy to treat and characterize when the above equations are applied to experimental data. Figure 2 shows an example of the elution profile (fractogram) obtained by running a mixture of four samples of "monodisperse" polystyrene latex beads. It is clear from the figure that a rather precise value of retention volume Vr can be identified with each bead size. With Vr known, it is easy to obtain R and X from Equation 5 and thence particle diameter d from Equation 4. This operation, as noted, yields diameters accurate to approximately 1-3%. 

Fig. 1 Fractograms of the polystyrene latex beads of 0.357 /xm (PSl) obtained by the direct injection of 1 julL of PSl (a) and by the concentration procedure of the PSl sample diluted in 10 mL of the carrier solution (b) using the conventional SdFFF technique, as well as of the a-Fe203 sample with nominal particle diameter of 0.271 tm diluted in 6 mL of the carrier solution obtained by the PBSdFFF concentration methodology (Ic).

Figure 8.8 Fractograms of crude oil samples at AT=158°C, showing the generation of characteristic elution patterns. The void peak (toluene) and the 2100 molecular mass polystyrene peak are shown for reference. Reprinted with permission from Anal. Chem. 47, 2389 1975...

Polystyrene standards were used as model samples to check the performance of micro-TFFF, to compare the results with those obtained previously with the use of a standard size TFFF channel, and to confirm that the ultrahigh molar mass (UHMM) PSs do not undergo shear degradation, observed frequently when separated by The fractogram of three PSs of different molar... 

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