Rapid multiresidue procedure for the determination of pesticides in anhydrous lanolin and lanolin-containing pharmaceutical preparations utilizing gel permeation chromatography cleanup with gas chromatographic and mass spectrometric techniques

1992 ◽  
Vol 40 (9) ◽  
pp. 1586-1590 ◽  
Author(s):  
David L. Heikes ◽  
John C. Craun
Keyword(s):  
Pharmaceutical Preparations ◽  
Gel Permeation Chromatography ◽  
Mass Spectrometric ◽  
Gel Permeation ◽  
Mass Spectrometric Techniques

scholarly journals Molar mass determination of lignins and characterization of their polymeric structures by multi-detector gel permeation chromatography

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Evamaria C. Gaugler ◽  
Wolfgang Radke ◽  
Andrew P. Vogt ◽  
Dawn A. Smith
Keyword(s):  
Molar Mass ◽  
Lithium Bromide ◽  
Gel Permeation Chromatography ◽  
Mass Determination ◽  
Organosolv Lignin ◽  
Gel Permeation ◽  
Softwood Kraft Lignin ◽  
Polymeric Structures

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.

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