Using a differential refractive index detector as a pressure transducer for online viscometry in exclusion chromatography

A differential refractive index (DRI) detector was tested as a pressure transducer for single capillary online viscometry in exclusion chromatography. The relationship between the detector response and pressure is linear, in agreement with the theoretically expected influence of pressure on refractive index and its dependence on temperature is negligible. Whole polymer and local intrinsic viscosities were determined and compared for narrow and, respectively, broad molecular weight distribution polymer samples. Considering that the detection system described can be improved, the results suggest that modern DRI detectors are susceptible to satisfy the requirements for a suitable pressure transducer in this application.