(353b) The Best of Both Worlds: Combining Advanced Polymer Chromatography with Advanced Multi-Detection for Complete High-Resolution Polymer Characterization

In recent years, new developments in the area of Size Exclusion Chromatography (SEC) have resulted in the introduction of Ultra High-Performance Liquid Chromatography (UHPLC or UPLC®) for polymer applications. Waters ACQUITY Advanced Polymer Chromatography (APC™) is a breakthrough technology that is able to provide SEC analyses of polymeric materials with higher-resolution and higher-speed than conventional SEC.

The new APC technology involves the use of high efficiency separation columns and a low dispersion flow path, resulting in:

• High resolution analysis
• Reduced time
• Reduced solvent consumption
• Reduced sample concentration
• Quick mobile phase changeover

However, the APC system is limited to conventional calibration, meaning it can only generate relative molecular weight information. In order to obtain comprehensive knowledge of the polymers under analysis, it is necessary to combine the high-resolution APC system with additional advanced detectors.

The combination of the Waters APC system with the Malvern Panalytical OMNISEC REVEAL (Figure 1) greatly widens the information attainable from a SEC analysis. OMNISEC REVEAL is an advanced detector system combining refractive index (RI), ultraviolet PDA (UV), light scattering (LS) and differential viscometry (IV). Using OMNISEC REVEAL the sample under analysis can now be fully characterized in terms of:

• Absolute molecular weight: without the need for column calibration
• Molecular weight distribution
• Size: hydrodynamic radius across the samples entire molecular weight range
• Structure: Mark-Houwink parameters and branching
• Composition

Combining the high-resolution separation obtained using an APC with a multi-detection system brings a number of challenges, most notable of which is band broadening. As a sample moves through the detector flow path it is stretched, essentially losing the resolution obtained on the column. OMNISEC REVEAL already benefits from a unique flow path with all the detectors connected in series and the RI detector, which typically introduces most band broadening, is the first detector in line. To fully realise the potential of the APC a new OMNISEC REVEAL has been developed with a significantly reduced internal volume designed specifically to maintain the APC resolution.

In this study, the analyses of several polymers by Waters APC combined with the Malvern Panalytical OMNISEC REVEAL multi-detector system are presented and discussed.