Characterizing Polyphenols in Food Using Chromatography
October 10th 2017There is a growing interest in polyphenols because of their noticeable antioxidant properties and their potential contribution to the defence against oxidative stress and protection against cardiovascular diseases and cancers. Oscar Núñez from the Department of Chemical Engineering and Analytical Chemistry at the University of Barcelona in Barcelona, Spain, has been working since 2010 in the analysis of polyphenols by capillary electrophoresis (CE), liquid chromatography (LC), mass spectrometry (MS), and chemometric techniques to achieve the characterization, classification, and authentication of natural products in the prevention of frauds. He recently spoke to The Column about this research.
Tips & Tricks: New and Old Approaches to Handle Unknown dn/dc in GPC/SEC-LS
October 10th 2017The intensity of the light scattering signal depends on concentration, molar mass, and the specific refractive index increment, dn/dc, of the sample. dn/dc therefore usually needs to be known to derive molar masses by gel permeation chromatography/size-exclusion chromatography-light scattering (GPC/SEC-LS). How to overcome the issue of unknown refractive index increments is outlined in this instalment of Tips & Tricks. In particular, a new approach to derive molar masses by GPC/SEC-LS that requires only the molar mass of a reference material, and not the dn/dc of the sample or of the reference material, is introduced.