title: Molar mass characterization of sodium carboxymethyl cellulose by SEC-MALLS.
abstract: Two series of sodium carboxymethyl celluloses (NaCMCs) derived from microcrystalline cellulose (Avicel samples) and cotton linters (BWL samples) with average degrees of substitution (DS) ranging from DS=0.45 to DS=1.55 were characterized by size exclusion chromatography with multi-angle laser light scattering detection (SEC-MALLS) in 100 mmol/L aqueous ammonium acetate (NH4OAc) as vaporizable eluent system. The application of vaporizable NH4OAc allows future use of the eluent system in two-dimensional separations employing evaporative light scattering detection (ELSD). The losses of samples during filtration and during the chromatographic experiment were determined. The scaling exponent as of the relation [Formula: see text] was approx. 0.61, showing that NaCMCs exhibit an expanded coil conformation in solution. No systematic dependencies of as on DS were observed. The dependences of molar mass on SEC-elution volume for samples of different DS can be well described by a common calibration curve, which is of advantage, as it allows the determination of molar masses of unknown samples by using the same calibration curve, irrespective of the DS of the NaCMC sample. Since no commercial NaCMC standards are available, correction factors were determined allowing converting a pullulan based calibration curve into a NaCMC calibration using the broad calibration approach. The weight average molar masses derived using the so established calibration curve closely agree with the ones determined by light scattering, proving the accuracy of the correction factors determined.
authors.affiliation: Fraunhofer-Institut für Betriebsfestigkeit und Systemzuverlässigkeit LBF, Bereich Kunststoffe, Schlossgartenstrasse 6, D-64289 Darmstadt, Germany.
authors.forename: Maryia
authors.initials: M
authors.lastname: Shakun
authors.forename: Helena
authors.initials: H
authors.lastname: Maier
authors.forename: Thomas
authors.initials: T
authors.lastname: Heinze
authors.forename: Peter
authors.initials: P
authors.lastname: Kilz
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Radke
mesh_terms: D000085:Acetates / Q000737:chemistry; D002266:Carboxymethylcellulose Sodium / Q000737:chemistry*; D002482:Cellulose / Q000737:chemistry; D002850:Chromatography, Gel; D008970:Molecular Weight
chemical_list: D000085:Acetates; D002482:Cellulose; D002266:Carboxymethylcellulose Sodium; C109691:microcrystalline cellulose; C018824:ammonium acetate