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首页> 外文期刊>Materials science & engineering >Characterization of stability, aggregation, and equilibrium properties of modified natural products; The case of carboxymethylated chitosans
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Characterization of stability, aggregation, and equilibrium properties of modified natural products; The case of carboxymethylated chitosans

机译：改性天然产物的稳定性，聚集性和平衡特性的表征；羧甲基化壳聚糖的情况

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摘要

Unstable biopolymer solutions inevitably lead to mis-characterization of macromolecular properties and irreproducible results. Even under stable or quasi-stable conditions, persistent aggregates can hamper reliable characterization, especially using light scattering methods. Various pitfalls in characterizing biopolymers were worked through, including determination of solution stability zones, dissolution kinetics, estimation of fraction of aggregate populations, and the relationship between batch and fractionation methods. Chitosans, polyampholytic biopolymers with isoelectric point around pH = 6.0, with varying degrees of carboxymethylation were studied. Instability was determined vs. pH and ionic strength using a high throughput screening method, simultaneous multiple sample light scattering (SMSLS). With stable solution conditions determined, equilibrium batch and multi-detector GPC characterization of molecular weight, intrinsic viscosity, and polyelectrolyte properties was made. Finally, a first attempt at continuous online monitoring of the modification reaction itself was made and compared to FTIR analysis of carboxymethylation on discrete aliquots. Given the range of possible characterization problems, multiple approaches with independent instruments may be required for reliable natural product characterization. Online monitoring of modification reactions may lead to rapid advances in understanding and preparation of natural products.
机译：不稳定的生物聚合物溶液不可避免地导致大分子特性的错误表征和不可再现的结果。即使在稳定或准稳定的条件下，持久的聚集体也会妨碍可靠的表征，尤其是使用光散射方法时。解决了表征生物聚合物的各种陷阱，包括溶液稳定性区的确定，溶解动力学，聚集体分数的估计以及分批与分馏方法之间的关系。研究了壳聚糖，等电点在pH = 6.0左右，羧甲基化程度不同的聚两性生物聚合物。使用高通量筛选方法，同时进行多个样品光散射（SMSLS），确定相对于pH和离子强度的不稳定性。在确定稳定的溶液条件的情况下，对分子量，特性粘度和聚电解质性质进行了平衡批处理和多检测器GPC表征。最后，首次尝试连续在线监测修饰反应本身，并将其与离散等分试样上的羧甲基化的FTIR分析进行比较。给定可能的表征问题的范围，可能需要使用独立仪器的多种方法来进行可靠的天然产物表征。在线监测修饰反应可能会导致对天然产物的了解和制备的快速发展。

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  • 来源
    《Materials science & engineering》 |2010年第1期|34-41|共8页
  • 作者

    Rilton Alves de Freitas; Michael F. Drenski; Alina M. Alb; Wayne F. Reed;

  • 作者单位

    Tulane Center for Polymer Reaction Monitoring and Characterization (PolyRMC), Tulane University, New Orleans, Louisiana, 70118, USA Pharmacy Dept., NIQFAR, Univali, Itajai, Brazil;

    Tulane Center for Polymer Reaction Monitoring and Characterization (PolyRMC), Tulane University, New Orleans, Louisiana, 70118, USA;

    Tulane Center for Polymer Reaction Monitoring and Characterization (PolyRMC), Tulane University, New Orleans, Louisiana, 70118, USA;

    Tulane Center for Polymer Reaction Monitoring and Characterization (PolyRMC), Tulane University, New Orleans, Louisiana, 70118, USA;

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  • 原文格式 PDF
  • 正文语种 eng
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  • 关键词

    characterization; physical stability; aggregation; equilibrium properties; carboxymethylchitosan;

    机译：表征;物理稳定性聚合;平衡特性羧甲基壳聚糖;

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