超高效凝胶色谱法测定聚乙二醇衍生物的分子量及其分布

采用超高效聚合物色谱(APC)技术,以单甲氧基聚乙二醇丙醛(m PEG_p ALD)为代表,测定了聚乙二醇衍生物的相对分子质量及其分布和杂质含量,优选了色谱柱和流动相,考察了样品质量浓度变化以及溶解时间等对测定结果的影响。优化后3根超高效凝胶色谱柱串联,在柱温40℃,流动相95%甲醇,流速0.5m L/min,示差折光检测条件下,对m PEG_p ALD的分子量及其分布进行测定,同时得到杂质的相对含量。结果测得m PEG_p ALD主成分的重均分子量(Mw)为19 444,分布指数(D)为1.01;杂质1的Mw为38 703,D为1.01,含量为1.31%;杂质2的Mw为61 036,D为1.00,含量为0.70%。与常规凝胶渗透色谱(GPC)相比,该方法分辨率高,分析速度快,能快速测定m PEG_p ALD的相对分子量及其分布,并能得到其纯度和杂质含量,为其工艺研发、质量控制提供了科学的依据,同时也可用于其它PEG衍生物的相对分子量及其分布和纯度的测定。

Determination of the Molecular Weight and Molecular Weight Distribution of Polyethylene Glycol Derivatives by Advanced Polymer Chromatography

A method of advanced polymer chromatography (APC) was established for the determination of the molecular weights and their distributions of polyethylene glycol derivatives and the impurity contents,with monomethoxy polyethylene glycol propyl aldehyde (mPEG_ pALD) as the representation for polyethylene glycol derivatives.The chromatographic conditions such as chromatographic column and mobile phase were optimized,while the effects of the concentration of sample (within the concentration range of 0.5-20 mg/mL) and dissolution time were also investigated.The optimized chromatographic conditions were as follows:three ultra-high performance gel columns were connected in series at 40 ℃ with methanol-water (95 ∶ 5,by volume) as mobile phase at a flow rate of 0.5 mL/min,and a refractive index detector was selected.The result showed that the weight-averaged molecular weight(Mw) of mPEG_ pALD was 19 444 and its distribution index(D) was 1.01,while the Mw for impurity 1 was 38 703 with its D index of 1.01 and its content of 1.31％,and the Mw for impurity 2 was 61 036 with its D index of 1.00 and its content of 0.70％.Compared with the traditional GPC method,this APC method could obtain the molecular weight and its distribution of mPEG_ pALD with higher resolution and less time,and the content of impurity could also be acquired.The method provides a scientific basis for the research,development and quality control of PEG derivatives,and is applicable for the determination of molecular weight,molecular weight distribution and purity of other PEG derivatives.