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An analysis of the accuracy of determining molar‐mass averages of polymers by GPC with an on‐line light‐scattering detector
Author(s) -
Procházka Ondřej,
Kratochvíl Pavel
Publication year - 1987
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1987.070340622
Subject(s) - molar mass , detector , virial coefficient , photometer , line (geometry) , calibration , analytical chemistry (journal) , dispersion (optics) , polymer , scattering , light scattering , chemistry , optics , materials science , chromatography , physics , mathematics , thermodynamics , geometry , organic chemistry , quantum mechanics
The effect of errors of concentration and molar‐mass detectors in GPC on the accuracy of determining molar‐mass averages M n and M w was analyzed. Model calculations show that by means of GPC with an on‐line low‐angle laser light‐scattering (LALLS) photometer only M w can be determined with acceptable accuracy. M n can be determined with acceptable accuracy only for polymers that have very small polydispersities. M n can be determined with greater accuracy from data of a concentration detector and chromatographic‐column‐calibration data. The most suitable procedure for the determination of M w seems to be a direct integration of the molar‐mass detector output, even if the error due to neglecting the second virial coefficient term is significant. Compared with the inaccuracy of detectors, axial dispersion appears not to be the main source of errors in GPC with an on‐line molar‐mass detector.