Size exclusion chromatography-viscometer system

A more sensitive viscometer than the drop-time glass capillary method is also needed in size exclusion chromatography (SEC) such as the gel permeation chromatographic (GPC) analysis of polymer molecular weight distribution (MWD). In an SEC system, a concentration detector is commonly used for providing the weight concentration profile of the polymer elution curve. 

The size exclusion chromatography for this study was done in the routine manner execept for the inclusion of an online viscosity detector called a Differential Viscometer <3> (Viscotek Corp., Porter, Texas, USAl. This instrument together with an RI concentration detector permits the calculation of intrinsic viscosities across the chromatogram. An IBM PC data system with software is also provided (5). The software acquires data from both detectors, and performs calculations of intrinsic viscosity and molecular weight distributions using the Universal Calibration Method. 

Size Exclusion Chromatography (SEC) is widely used technique polymer characterization. The standard configuration of a SEC apparatus consists of three parts (/-5), viz., a solvent-delivery system (equipped widi an injection port), the columns, and a differential refractive index (RI) detector. This basic configuration can be modified by adding an additional detector, either in series or in parallel to the RI detector (J-5). The second detector can be a viscometer (2), a concentration detector (3), an UV detector (4) or a Light Scattering (LS) device (5),... 

Figure 3.36. Size exclusion chromatography system with an on-line viscometer and a lightscattering detector allows to create the Mark-Houwink-Sakurada plot without fractionating the polymer somewhere else. The concentration is detected by a refractive index detector or an ultraviolet absorption detector.

---