Polystyrene broad standards, universal

Figure 1. Master universal calibration curve obtained with a Beckman /z-Spherogel column system in THF. The fit of narrow MWD standards, polystyrene star polymers, and a single broad MWD standard (calculated with Unical 2.71 software) are shown.

Values for system peak parameters were found using a narrow distribution polystyrene standard (PS68K) before calculating MWD data for the lignin samples from universal calibration. To check software and instrument operation, several narrow MWD polystyrene and one broad MWD polymethylmethacrylate standards were treated as unknown samples and subjected to analysis with the universal calibration curve assembled from all polymer standards files. It was found that the MWD could be estimated for the recalculated polymer standards with errors between 5 and 10% of the original value indicated by the supplier of the standard (e.g., Mw for PS11K and Mw and M for PMMA17K-6). 

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