Statistical methods for comparing GPC curves

Abstract

SynopsisThe possibilities of comparing the GPC curves of two or more polymers were studied, and the method of "distinguished points" (DPs) is suggested for this purpose. The features of these DP values as random variables were investigated. According to the experimental results they meet the requirements of the statistical tests applied in this text. In order to indicate the significant deviation or the agreement of the DP values of GPC curves of two polymers, the sequential U and t tests are suggested, because with these methods the number of the necessary parallel measurements is considerably decreased, and one can also decide on the magnitude of the variation one must be able to detect, while in the case of more than two polymers the methods of the analysis of variance can be utilized. The molecular weight ranges in which significant differences occur can also be determined. The described methods were tested by materials of known molecular weight distributions.