Report on cooperative determination of molecular weight averages of polymers by size exclusion chromatography. II. A report on the second round robin test (No. 1)

Abstract

Molecular weight averages of four polystyrenes (PS) and two poly(methylmethacrylates) (PMMA) were determined by size exclusion chromatography at 26 laboratories belonging to the section of special study on SEC. Polymer standards for constructing a calibration curve were delivered to the laboratories. Sample concentrations, the injection volume and the procedure for drawing the baseline were prescribed. Other experimental conditions were the same as in the previous report. Relative standard deviations (RSD) of over-all mean molecular weight averages were as follows after rejecting the suspected result in each set of data: 13.7-15.8% for PS number-average; 5.0-5.8% for PS weight-average; 11.9-13.3% for PMMA number-average; and 10.9-11.3% for PMMA weight-average. Compared with the results for the former round robin test, RSD was not improved much because the procedure for drawing the baseline was not restricted strictly.