Abstract
This work describes the determination of the band broadening function (BBF) in a size exclusion chromatograph fitted with 2 mixed-gel columns, a light scattering (LS) detector, and a differential refractometer (DR). The raw data were the chromatograms of 4 narrow polystyrene standards. First, the interdetector volume shift was indirectly estimated from its upper and lower limiting values. Then, for each of the standards, their “local” BBFs were estimated by application of an existing theoretical method. Each local BBF is an assumed elution-volume invariant in the narrow ranges of the analyzed standards and is represented by an exponentially-modified Gaussian of standard deviation σBB and exponential decay τBB. Finally, a “global” BBF (valid for the complete fractionation range) was interpolated from the local BBF parameters. For increasing elution volumes, the global BBF exhibits an increasing σBB and a decreasing τBB. In addition, the asymmetry factor [τBB/σBB] and the global variance [] both decrease with elution volume.
ACKNOWLEDGMENTS
This work was supported by the IUPAC project “Data Treatment in SEC and Other Techniques of Polymer Characterization. Correction for Band Broadening and Other Sources of Error” (http://www.iupac.org/web/ins/2009-019-2-400); by an international cooperation project between CONICET and the Slovak Academy of Sciences (SAS), and by the following Argentine institutions: ANPCyT (MinCyT), Universidad Nacional del Litoral, and Universidad Tecnológica Nacional.
Notes
The averages of rows (a) were calculated from s DR(V) and logM(V) of Figure 1. The averages of rows (b) were calculated from s DR(V+δ) and logM w(V) as obtained through Eq. (Equation1) with δ = 0.0733 mL.
*Estimated from . **Characterized by MALDI-ToF.