MEASUREMENT OF NARROW-DISTRIBUTION POLYDISPERSITY USING MULTIANGLE LIGHT-SCATTERING

Molecular radius information obtained with multi-angle laser light scattering combined with gel permeation chromatography was used to obtain an upper limit for the polydispersity (M) over bar(w)/(M) over bar(n) of a narrow-distribution polystyrene standard dissolved in toluene. The radius obtained by light scattering is independent of any other detector and so is not affected by interdetector delay volumes or interdetector broadening. The value obtained for (M) over bar w/(M) over bar(n) was 1.00096 +/- 0.00004, much closer to unity than previously reported. Column broadening was found to be responsible for nearly all the observed peak width.