Size exclusion chromatography of polymers with molar mass detection. computer simulation study on instrumental broadening biases and proposed correction method

摘要

This theoretical work evaluates the errors in average molecular weights due to instrumental broadening when a size exclusion chromatograph is fitted with ideal on-line M-bar_n or M-bar_w sensors, and a correction method is proposed to compensate for such errors. The basic assumptions are that linear homopolymers are analyzed, and that the instrumental broadening is uniform. It was verified that an ideal molar mass detector systematically underestimates the polydispersity and that such bias may be simply obtained from the spreading function polydispersity. The correction method uses an estimate of the instantaneous polydispersity. Such function can be directly obtained from the spreading function alone, since it is proven to be little dependent on the shape of the analyzed MWD.