以聚乙二醇作为凝胶渗透色谱参比标准测定聚丙烯酸相对分子质量的误差问题

On the Error of Relative Molecular Mass of Polyacrylic Acid Determined by GPC Using Polyethylene Glycol as Reference Standard

通过与自制聚丙烯酸作参比标准相对比,研究了凝胶渗透色谱分析中,采用非电解质类的聚乙二醇作为参比标准,测定聚电解质类的聚丙烯酸试样相对分子质量的误差问题。结果表明:以自制参比标准测定聚丙烯酸试样的相对分子质量结果较准确,与黏度法相比不存在系统误差,随机误差小于10%。采用聚乙二醇参比标准测定聚丙烯酸试样的相对分子质量,无论采用直接校正法或普适校正法均无法得到满意的结果,两种校正方法的误差均在40%以上,且测得相对分子质量分布系数均小于理论值。聚乙二醇参比标准不适宜直接用于聚电解质聚丙烯酸相对分子质量的测定。

A study on the error of relative molecular mass of polyelectrolyte polyacrylic acid（PAA） determined by gel permeation chromatography（GPC） using the nonelectrolyte polyethylene glycol（PEG） as reference standard was made as compared with the use of selfprepared PAA as reference standard.It was found that more accurate relative molecular mass of PAA was obtained by using the self-prepared PAA as reference standard.No significant systematic error was found as compared with the results obtained by the viscosimetry,with values of random error less than 10%.When PEG was used as reference standard,unsatisfactory results of relative molecular mass of samples of PAA were obtained by either the direct calibration or the universal calibration,giving deviations over 40%,and values of distribution coefficient of relative molecular mass less than the theoratical value.Hence,the non-electrolyte PEG was not feasible to be used as reference standard in the determination of relative molecular mass of PAA by GPC.