目的　采用高效阴离子交换色谱-脉冲安培法（high-performance anion-exchange chromatography with pulsed amperometric detection，HPAEC-PAD）检测A群脑膜炎球菌多糖-破伤风类毒素结合疫苗（group A meningococcal polysaccharide-tetanus toxoid conjugate vaccine，MenA-PS-TT）中的游离多糖含量。方法　采用1%脱氧胆酸钠（sodium deoxycholate，DOC）处理MenA-PS-TT分离游离PS，游离和结合PS经三氟乙酸水解后，用HPAEC-PAD检测水解产物，并将检测结果与改良钼酸铵分光光度法的检测结果进行比较。 结果　1%DOC处理的样品的PS回收率为90%～104%，TT沉淀率为99%以上，说明1%DOC处理不会对游离和结合PS产生影响。HPAEC-PAD检测MenA-PS的重复性良好，3次MenA-PS标准品定位结果和3次MenA-PS-TT成品检测结果的相对标准偏差为1.7%和6.4%。HPAEC-PAD与改良钼酸铵分光光度法的检测结果相当。结论　HPAEC-PAD可用于MenA-PS-TT中的游离PS含量检测。

 Objective   To detect free polysaccharide contents in group A meningococcal polysaccharide tetanus toxoid  conjugate vaccine (MenA-PS-TT) by high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD).  Methods   The free PSs were separated from MenA-PS-TT using 1% sodium deoxycholate (DOC). The free and conjugate PSs were hydrolyzed with trifluoroacetic acid, and the hydrolyzates were detected by HPAEC-PAD. The results obtained by HPAEC-PAD were compared with those by improved ammonium  molybdate spectrophotometric method.  Results   After the samples were treated with 1% DOC, the recovery rates of PS were 90%-104%, and the precipitation rates of TT were above 99%. The study showed that 1% DOC treatment had no effect on the free and conjugate PSs. HPAEC-PAD for determination of MenA-PS had good repeatability, and relative standard deviation of detection results  of  MenA-PS standard and detecting results of ManA- PS-TT final products for 3 times were 1.7% and 6.4%，respectively. The results between HPAEC-PAD and improved ammonium molybdate spectrophotometric method were similar.  Conclusion   HPAEC-PAD can be applied for determination of free PS contents in MenA-PS-TT.