Determination of bimodal molar mass distribution functions of polystyrene by photon correlation spectroscopy: numerical simulations and experimental realization in comparison with gel permeation chromatography data

1988 ◽  
Vol 21 (2) ◽  
pp. 415-420 ◽  
Author(s):  
Gyula Vancso ◽  
Ivan Tomka ◽  
Klara Vancso-Polacsek
2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Evamaria C. Gaugler ◽  
Wolfgang Radke ◽  
Andrew P. Vogt ◽  
Dawn A. Smith

AbstractMolar masses, Mark-Houwink-Sakurada (MHS) exponents, and refractive index increments (dn/dc) for three lignins were determined without derivatization by multi-detector gel permeation chromatography (GPC) in dimethylformamide (DMF) with 0.05 M lithium bromide (LiBr). The lack of effectiveness of fluorescence filters on molar mass determination by GPC-multi-angle laser light scattering (MALS) was confirmed for softwood kraft lignin (Indulin AT) and revealed for mixed hardwood organosolv lignin (Alcell) as well as soda straw/grass lignin (Protobind 1000). GPC with viscometry detection confirmed that these lignins were present as compact molecules. The MHS exponent α for Indulin AT and Alcell was in the order of 0.1. Additionally, the intrinsic viscosity of Protobind 1000 for a given molar mass was much lower than that of either Alcell or Indulin AT. This is the first report of dn/dc values for these three lignins in DMF with 0.05 M LiBr.


1989 ◽  
Vol 72 (3) ◽  
pp. 436-441
Author(s):  
Terry D Cyr ◽  
Robert C Lawrence ◽  
Edward G Lovering

Abstract A photon correlation spectroscopy method has been developed to characterize the size distribution of fat globules in intravenous fat emulsions (IFE) in terms of mean diameter, standard deviation of the distribution, and percentage of large particles outside the distribution. Mean fat globule diameters of samples of all IFE products available in Canada were about 0.3 μm, similar to values reported in the literature. The methodology is sufficiently sensitive to detect the presence of 5% by weight of 2 μm polystyrene microspheres in an intravenous fat emulsion. The effect of changes in instrument settings and variables on the results has been evaluated.


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