Comparative Study on Molecular Weight of Konjac Glucomannan by Gel Permeation Chromatography-Laser Light Scattering-Refractive Index and Laser Light-Scattering Methods

Abstract

The gel permeation chromatography, combined with laser light scattering and refractive index (GPC-LLS-RI) online method and laser light scattering (LLS) single method, researched the weight-average molecular weight (Mw) of konjac glucomannan (KGM) in this paper. The results show that the determination results of molecular weight of KGM are similar by two method, the molecular weight of KGM is<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"><mml:mrow><mml:mn>2.476</mml:mn><mml:mo>×</mml:mo><mml:msup><mml:mrow><mml:mn>10</mml:mn></mml:mrow><mml:mn>5</mml:mn></mml:msup></mml:mrow></mml:math> g/mol by online method measured, and it is<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M2"><mml:mrow><mml:mn>2.508</mml:mn><mml:mo>×</mml:mo><mml:msup><mml:mrow><mml:mn>10</mml:mn></mml:mrow><mml:mn>5</mml:mn></mml:msup></mml:mrow></mml:math> g/mol by single method measured, compared with only 1.3% difference between the two methods. At the same time, the molecular weight distributions of KGM and conformation index were analyzed by online method, while the second virial coefficient (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M3"><mml:mrow><mml:msub><mml:mrow><mml:mi>A</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>) that characterizes the interaction between KGM molecules and solvent molecules was acquired by single method, which can provide reliable foundation for the molecular chain morphology research of KGM.