Todorov Todor I, Yamaguchi Yoshinori, Morris Michael D
Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, USA.
Anal Chem. 2003 Apr 15;75(8):1837-43. doi: 10.1021/ac026325a.
The present study describes the effect of urea on the properties of hydroxyethyl cellulose (HEC) polymer solutions used for the separation of nucleic acids. Solution properties were investigated by viscosity measurements and supplemented by Raman spectroscopy of the solution components. By using viscosimetry, it was possible to identify that borate, urea, and HEC participate in an interaction causing an increase in the viscosity of dilute solutions. In addition, short polymer chains exhibited a 4-fold decrease in the entanglement threshold in the presence of 4 M urea and 0.356 M total borate concentration. These interactions were found to be specific to HEC. Raman spectroscopy monitored serial addition of 8 M urea to HEC sieving solutions combined with factor analysis indicated formation of minor urea species. Lack of change in the Raman spectrum and relative amount of borate suggested that there is no direct interaction between borate and urea. These effects on HEC sieving solution properties lead to the use of low HEC concentrations that are beneficial for the separation of nucleic acids under denaturing conditions.
本研究描述了尿素对用于核酸分离的羟乙基纤维素（HEC）聚合物溶液性质的影响。通过粘度测量研究溶液性质，并辅以溶液成分的拉曼光谱分析。通过使用粘度测定法，可以确定硼酸盐、尿素和HEC参与了一种相互作用，导致稀溶液粘度增加。此外，在4M尿素和0.356M总硼酸盐浓度存在下，短聚合物链的缠结阈值降低了4倍。发现这些相互作用是HEC特有的。拉曼光谱监测了向HEC筛分溶液中连续添加8M尿素，并结合因子分析表明形成了少量尿素物种。拉曼光谱和硼酸盐相对含量没有变化，表明硼酸盐和尿素之间没有直接相互作用。这些对HEC筛分溶液性质的影响导致使用低HEC浓度，这有利于在变性条件下分离核酸。
