Quantification in the analysis of polyethylene glycols and their monomethyl ethers by liquid adsorption chromatography with different detectors.
It is shown that the molar mass distribution of polyethylene glycols (PEGs) and their monomethyl ethers can be determined by liquid adsorption chromatography (LAC) on reversed phases using isocratic or gradient elution. In gradient LAC, the evaporative light scattering detector (ELSD) has to be used, which is, however, problematic with respect to quantification. The response factors of the individual oligomers depend strongly on the operating conditions, molar mass, and sample size. These problems do not arise with density and refractive index detection, which can, however, only be applied with isocratic elution. A comparison of the results obtained with these three detectors showed that calibration of the ELSD has to be performed very carefully.
Central Polymer Laboratory/Molecular Characteristics (CePol/MC), Institute of Chemistry, Karl-Franzens-University, 8010 Graz, Austria. bernd.trathnigg@uni-graz.at
Bernd
B
Trathnigg
Hasnat
H
Ahmed
D000327:Adsorption; D002853:Chromatography, Liquid; D004987:Ethers / Q000032:analysis*; D008027:Light; D010316:Particle Size; D011092:Polyethylene Glycols / Q000032:analysis*; D012542:Scattering, Radiation
D004987:Ethers; D011092:Polyethylene Glycols