高效液相色谱法测定硝酸甘油气雾剂定量阀门中5种抗氧剂含量与迁移量研究

目的 建立同时测定硝酸甘油气雾剂定量阀门中5种常见抗氧剂含量的高效液相色谱(HPLC)法,并考察抗氧剂在其中的迁移情况。方法 色谱柱为Inertsil?ODS-SP柱(150 mm×4.6 mm,5μm),流动相为水-四氢呋喃-乙腈(10∶30∶60,V/V/V),流速为1.5 mL/min,柱温为30℃,检测波长为280 nm,进样量为20μL。结果 抗氧剂168、抗氧剂330、抗氧剂1010、抗氧剂1076、抗氧剂2,6-二叔丁基对甲酚(BHT)的质量浓度均在0.2~250μg/mL范围内与峰面积线性关系良好(r≥0.999 8,n=6);检测限分别为1.58,0.27,0.38,0.94,0.24μg/mL;定量限分别为3.84,0.91,1.44,3.02,0.60μg/mL;精密度、稳定性、重复性试验结果的RSD均小于2.0%(n=6);回收率分别为100.67%,99.97%,99.93%,99.60%,99.63%,RSD分别为0.47%,0.21%,0.93%,0.44%,0.60%(n=9)。硝酸甘油气雾剂定量阀门组件材料(内垫圈、阀杆、阀室、吸管)中抗氧剂168、抗氧剂330、抗氧剂1010、抗氧剂1076的检出量均低于其评价阈值(AET),均未检出抗氧剂BHT。加速试验0个月、3个月、6个月,定量阀门组件材料中抗氧剂168、抗氧剂330、抗氧剂1010、抗氧剂1076、抗氧剂BHT的迁移量均低于其AET。结论 该方法操作简单、灵敏度高、结果准确、重复性和稳定性均较好,可用于硝酸甘油气雾剂定量阀门中5种抗氧剂的含量测定及迁移量研究。

Position Control for Asymmetrical Hydraulic Cylinder System Using a Single On/Off Valve

A single on/off valve is used to carry out the position control of the asymmetrical hydraulic cylinder. The influence of the nominal flow rate on the positional accuracy of piston is investigated and the proximate formula for calculating the nominal flow rate of on/off valve is introduced. The system structure proposed in this paper could avoid cavitation and hyper pressure in two chambers to some extent. The simulation results indicated that the control method in this paper could satisfy the expected control requirements.