LINEAR COPOLYMER ANALYSIS WITH DUAL-DETECTION SIZE EXCLUSION CHROMATOGRAPHY - CORRECTION FOR INSTRUMENTAL BROADENING

This article deals with data treatment problems associated with the estimation of the combined distribution of molecular weights and chemical composition in linear copolymers by size exclusion chromatography, when correction for instrumental broadening is considered. Standard dual detection is assumed, i.e., the chromatograph is fitted with a "universal" detector (a differential refractometer) and a specific sensor to one comonomer only (a UV spectrophotometer). A real and a "synthetic" example (involving the analysis of a diblock styrene-butadiene rubber) are presented. Also, a propagation of errors study associated with the deconvolution operations is developed. It is concluded that the best calculation procedure is to first compute the combined distributions from the raw chromatograms and then correct such distributions for instrumental broadening.