顶空气相色谱-质谱法测定低取代羟丙纤维素中羟丙氧基的含量

Determination of hydroxypropoxy in low substituted hydroxypropyl cellulose by headspace gas chromatography-mass spectrometry

目的建立顶空气相色谱-质谱法(gas chromatography-mass spectrometry,GC-MS)测定低取代羟丙纤维素中羟丙氧基的含量。方法样品在顶空瓶中与氢碘酸反应,使羟丙氧基转为2-碘丙烷,反应结束后加碱液中和过量的氢碘酸防止腐蚀进样器和色谱柱,随后顶空进样,以HP-5MS毛细管柱分离,GC-MS选择离子检测模式测定。结果羟丙氧基的浓度在0.6435～17.26025 mg/mL的范围内线性关系良好,相关系数r>0.999;此方法的检出限(S/N=3)为0.039μg/mL,定量限(S/N=10)为0.13μg/mL;在不同添加水平下,方法的平均回收率为99.4%,相对标准偏差为1.3%(n=3)。结论该方法简便、快速、灵敏、准确,适合羟丙氧基定性和定量测定。

Objective To establish a method for determination of hydroxypropoxy in low substituted hydroxypropyl cellulose（L-HPC） by head space gas chromatography-mass spectrometry（GC-MS）. Methods The sample was reacted with the hydrogen iodide in headspace bottle, and the hydroxypropyl was converted to 2-iodopropane. After the reaction, excess hydrogen iodate was neutralized with adding lye to prevent corrosion of the sampler and chromatographic column. Then the samples were injected and HP-5MS capillary column was used for separation, and the selected ion detection mode of GC-MS was used for determination. Results Hydroxypropoxyhad a good linear relationship in the range of 0.6435～17.26025 mg/mL, and the correlation coefficient was larger than 0.999. The limit of detection（S/N=3） was 0.039 μg/mL, and limit of quantitation（S/N=10） was 0.13 μg/mL. The average recovery of the method at different spiked levels was 99.4%, with the relative standard deviations of 1.3%（n=3）. Conclusion The method is simple, rapid, sensitive and accurate, which is suitable for the qualitative and quantitative determination of hydroxypropyl.