Molar mass characterization of sodium carboxymethyl cellulose by SEC-MALLS.
Molar mass characterization of sodium carboxymethyl cellulose by SEC-MALLS.
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DOI：
10.1016/j.carbpol.2013.03.028
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发表时间：
2013-06
影响因子：
11.2
通讯作者：
M. Shakun;H. Maier;T. Heinze;P. Kilz;W. Radke
中科院分区：
文献类型：
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作者：
M. Shakun;H. Maier;T. Heinze;P. Kilz;W. Radke
采用体积排阻色谱-多角度激光散射检测（SEC-MALLS）技术，以100 mmol/L乙酸铵（NH_4OAc）水溶液为洗脱剂，对微晶纤维素（Avicel样品）和棉短绒（BWL样品）两个系列的羧甲基纤维素钠（NaCMCs）进行了表征。可蒸发的NH 40 Ac的应用允许将来在采用蒸发光散射检测（ELSD）的二维分离中使用洗脱剂系统。测定了过滤过程中和色谱实验过程中样品的损失。关系式[公式：见正文]的标度指数约为。0.61，表明NaCMC在溶液中表现出膨胀的卷曲构象。未观察到ason DS的系统依赖性。不同DS样品的摩尔质量对SEC洗脱体积的依赖性可以通过共同的校准曲线很好地描述，这是有利的，因为它允许通过使用相同的校准曲线测定未知样品的摩尔质量，而与NaCMC样品的DS无关。由于没有商业NaCMC标准品可用，因此确定校正因子，从而允许使用广泛的校准方法将基于普鲁兰的校准曲线转换为NaCMC校准。使用如此建立的校准曲线导出的重均摩尔质量与通过光散射测定的重均摩尔质量密切一致，证明了测定的校正因子的准确性。
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 100mmol/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 asof the relation [Formula: see text] was approx. 0.61, showing that NaCMCs exhibit an expanded coil conformation in solution. No systematic dependencies of ason 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.