注射称量法配气中的称量线性研究及不确定度评定
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摘要
采用称量法制备混合气体,当加入的原料组分为微量液体时,需要使用气密性良好的注射器进行液体组分的转移。通过准确称量注射器转移前后的质量差来计算加入液体组分的质量,因此需要使用高灵敏度、低载荷的天平。选择称量重复性好的质量比较器,使用标准砝码研究了质量比较器的称量线性关系,建立了注射法加入液体质量的数学模型,评定了该方法的不确定度。使用该方法制备了两瓶氮中苯的混合气体,通过气相色谱进行了一致性分析,对称量过程中引入的不确定度进行了验证。
As the gas mixtures are prepared gravimetrically and the mass of liquid is normally small,using a gas-tight syringe to inject liquid components into gas mixtures is considered to be a delicate introduction method. The mass difference between the syringe with and without liquid is the introduced liquid mass,so a highly sensitive and low capacity balance is required. In this work,a mass-comparator with brilliant repeatability was chosen to do the weighing process,the weighing linearity was checked using standard mass pieces,and a mathematical description of the injection method was established and its uncertainty was evaluated.Then two binary gas mixture of benzene in nitrogen were prepared and verification was done by GC analyzing.
As the gas mixtures are prepared gravimetrically and the mass of liquid is normally small,using a gas-tight syringe to inject liquid components into gas mixtures is considered to be a delicate introduction method. The mass difference between the syringe with and without liquid is the introduced liquid mass,so a highly sensitive and low capacity balance is required. In this work,a mass-comparator with brilliant repeatability was chosen to do the weighing process,the weighing linearity was checked using standard mass pieces,and a mathematical description of the injection method was established and its uncertainty was evaluated.Then two binary gas mixture of benzene in nitrogen were prepared and verification was done by GC analyzing.
引文
[1]The International Organization for Standardization.ISO6142-1 Gas analysis-preparation of calibration gas mixture-Part 1:gravimetric method for class I mixtures[S].2015-08-01.
[2]International Organization of Legal Metrology.OIML R111-1 International recommendation[S].2004.
[3]NOBUHIRO M,TAKURO W,MASAAKI M,et al.Development of mass measurement equipment using an electronic mass-comparator for gravimetric preparation of reference gas mixtures[J].Metrologia,2004,41(3):178-188.
[4]ALINK A,VAN D V.Uncertainty calculations for the preparation of primary gas mixtures[J].Metrologia,2000,37(6):641-650.
[5]MILTON M J T,VARGHA G M,BROWN A S.Gravimetric methods for the preparation of standard gas mixtures[J].Metrologia,2011,48(5):1-9.
[6]胡树国,王德发,韩桥,等.注射重量法制备气体标准物质中液体称量的数学模型和不确定度评价[J].低温与特气,2012,30(4):31-34.
[7]方正,潘义,江月军,等.称量法制备气体标准物质的称量相对标准不确定度评定方法研究[J].中国测试,2012,38(6):5-12.
[8]方正,周鑫,潘义.氮气中1μmol·mol-1硫化氢气体标准物质的研制[J].化学研究与应用,2014,26(11):1 809-1 812.
[2]International Organization of Legal Metrology.OIML R111-1 International recommendation[S].2004.
[3]NOBUHIRO M,TAKURO W,MASAAKI M,et al.Development of mass measurement equipment using an electronic mass-comparator for gravimetric preparation of reference gas mixtures[J].Metrologia,2004,41(3):178-188.
[4]ALINK A,VAN D V.Uncertainty calculations for the preparation of primary gas mixtures[J].Metrologia,2000,37(6):641-650.
[5]MILTON M J T,VARGHA G M,BROWN A S.Gravimetric methods for the preparation of standard gas mixtures[J].Metrologia,2011,48(5):1-9.
[6]胡树国,王德发,韩桥,等.注射重量法制备气体标准物质中液体称量的数学模型和不确定度评价[J].低温与特气,2012,30(4):31-34.
[7]方正,潘义,江月军,等.称量法制备气体标准物质的称量相对标准不确定度评定方法研究[J].中国测试,2012,38(6):5-12.
[8]方正,周鑫,潘义.氮气中1μmol·mol-1硫化氢气体标准物质的研制[J].化学研究与应用,2014,26(11):1 809-1 812.