Pullulan calibration curve

Figure 2. Pullulan calibration curve for SEC analysis of Alginates...

Figure 6.21 shows the calibration curves of the SB-800 HQ series using standard pullulan. Because a high molecular weight standard sample is not available, the calibration curves of 805 and 806 are partly estimates (dotted lines). The difference in the conformation between polyethylene oxide (PEO) and pullulan in the solvent causes a shift of the calibration curves of pullulan slightly higher than those of PEO. The OHpak SB-800HQ series is better suited for the analysis of hydrophilic samples than the Asahipak GS/GE series. 

FIGURE 6.40 Calibration curves of Shodex PROTEiN KW-800 series. Column Shodex PROTEiN KW-802.S, KW-803, KW-804, 8.0 mm i.d. X 300 mm. Eiuent Pullulan, PEG PEO Purified water, Protein SO mM Sodium phosphate buffer + 0.3 M NaCI (pH 7.0). Flow rate 1.0 mL/min. Detector Pullulan. PEG PEO Shodex Rl Protein Shodex UV (220 nm). Column temp. Ambient. 

Each stationary phase is characterised by a calibration curve made with iso-molecular standards of known masses, M polystyrene in THF or polyoxyethylenes, pullulanes, polyethyleneglycols in water (Fig. 7.3 and Table 7.1). The curves representing log(M) as a function of the elution volume have a sigmoidal shape. However, by mixing stationary phases, the manufacturers can provide columns for which the calibration curves are almost linear for a wide range of masses. 

There is a limited number of polymers for which narrow MWD standards are commercially available polystyrene, poly(methyl methacrylate), poly(a-methyl styrene), polyisoprene, polybutadiene, polyethylene, poly(dimethyl siloxane), polyethyleneoxide, pullulan, dextran, polystyrene sulfonate sodium salt, and globular proteins. In some cases, the standards available cover a limited molecular weight range, so it may be impossible to construct the calibration curve over the complete column pore volume. 

Universal calibration curve established with a Viseotek Model 100 differential viscometer detector. Calibration standards are narrowly distributed pullulans at 0.12% concentration. All other eonditions as in Figure 8. 

Plot of molecular weight Mpui vs elution volume v for pullulans (filled squares and solid curve) and proteins (open circles) eluted through the PHEMA-grafted monolithic column. The molecular weights of the proteins are the reduced values independently determined by pullulan-calibrated GPC. The arrow head shows the so-called ghost peak of the eluent. The flow rate was 0.2 ml/min with PBS as eluent at room temperature. The inset shows a cartoon illustrating two size-exclusion modes of the brush-modified monolith. 

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