静态配气法制备对二甲苯标准吸附管

Preparation of p-xylene standard adsorption tubes by static gas distribution method

利用静态配气法(注射器配气)稀释已知浓度对二甲苯钢瓶标准气,用Tenax管吸附稀释后气体,通过稀释倍数确定对二甲苯浓度。用热解吸-气相色谱法分析对二甲苯标准吸附管,与稀释后的对二甲苯浓度理论值相比,相对误差为2.76%~4.07%,相对扩展不确定度为0.01(k=2)。对二甲苯标准吸附管批内相对标准偏差为2.4%(n=6),批间相对标准偏差为4.5%(n=6)。制备同一批次对二甲苯标准吸附管,每月分析此对二甲苯标准吸附管中对二甲苯的含量,为期一年,标准管实测值与理论值相比,相对误差小于10%。该方法制备对二甲苯标准吸附管,所用设备简单,操作简便,标准吸附管易于存放,可用于日常监测的质量控制。

The standard gas of the cylinder with known concentration of p-xylene was diluted by static gas distribution method(syringe gas distribution),and the diluted gas was adsorbed by Tenax tube,and the concentration of p-xylene was determined by dilution ratio.The relative error was 2.76%-4.07%and the relative expansion uncertainty was 0.01(k=2)compared with the theoretical value of paraxylene concentration after dilution by thermal desorption gas chromatography.The relative standard deviation within the batch and the relative standard deviation between the batch were 2.4%(n=6)and 4.5%(n=6).The same batch of p-xylene standard adsorption tube was prepared,and the content of p-xylene in the p-xylene standard adsorption tube was analyzed every month for one year.The relative error of the measured value of the standard tube was less than 10%compared with the theoretical value.The preparation of the p-xylene standard adsorption tube is simple in equipment and operation,and the standard adsorption tube is easy to store and can be used for quality control of daily monitoring.