Molecular mass distribution analysis of ethyl(hydroxyethyl)cellulose by size-exclusion chromatography with dual light-scattering and refractometric detection.
Dual low-angle light scattering and refractometric detection coupled to size-exclusion chromatography provided proof for the presence of a low amount of stable aggregates/particles in ethyl(hydroxyethyl)cellulose. Unlike the correct size-exclusion chromatographic behavior of the parent polysaccharide itself, the aggregates exhibit variable size-dependent weak retention as a function of flow-rate and of ionic strength of the aqueous mobile phase. Therefore, determination of the molecular mass of non-aggregated polymer is possible in aqueous mobile phase containing 0.1 M NaCl under conditions at which aggregates are completely adsorbed on the column packing irrespective of the flow-rate used. Flow-rate and ionic strength-dependent variations of aggregate behavior as well as model size-exclusion experiments with latex particles indicate that they partly carry a minute charge and have a compact structure. Their weak retention under the separation conditions used suggests a difference in their surface chemistry when compared with the dissolved polymer coils which exhibit a correct size-exclusion behavior.
Porsch
Bedrich
B
Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Prague. porsch@imc.cas.cz
Andersson
Mats
M
Wittgren
Bengt
B
Wahlund
Karl-Gustav
KG
D002482:Cellulose / Q000031:analogs & derivatives / Q000737:chemistry*; D002850:Chromatography, Gel / Q000379:methods*; D008027:Light; D008970:Molecular Weight; D012031:Refractometry; D012542:Scattering, Radiation
C462399:ethyl(hydroxyethyl)cellulose; D002482:Cellulose