| Automobile exhaust is one of the main sources of air pollutants.The use of gasoline oxygenated additives can effectively improve the quality of oil,and reduce the generation of harmful substances in automobile exhaust.However,excessive use may lead to the increase of harmful substances,and affect the performance of the engine.Environmental pollution and health hazards caused by oxygenated additives cannot be ignored.Now,the market price of oil fluctuates and many kinds of blended gasoline are flooding into the market,which pose a severe challenge to economic development and people’s healthy living.The corresponding detection methods have been established both at home and abroad.However,due to the lack of relevant purity certified reference materials,it’s hard to ensure the accuracy,reliability,comparability,and traceability of the detection methods and results.This work is funded by the project of research and application of the national quality—"Metrology study on the key impurities in organic substance"(2017YFF0205803).In this research,chemical separation technology was utilized to high-purity certified reference materials.The research on the key impurities determination technology of the mass balance approach(MBA)and the research on the traceability technology of quantitative nuclear magnetic resonancemethod(qNMR)were carried out to develop purity certified reference materials of gasoline oxygenated additives such as alcohol and ether.The main work and conclusions were as following:1.Taking the typical substance tert-amyl methyl ether(TAME)as an example,a overall analysis method for raw materials was established:based on the analysis technologies of GC、MS、KFT、ICP-MS,the purity of raw materials and typical impurities were analyzed.The experimental results showed that the purity of raw materials was 98.725%.2.Research on the purification and preparation of TAME:The high purity product was prepared by the coupling process of precise distillation and adsorption.The process parameters were optimized,and the optimal purification process conditions were established to remove impurities.Most trace impurities were removed by precise distillation and the tipical impurity tert-amyl alcohol was removed by adsorption with alkaline alumina.3.Research on the mass balance approach for key impurities:The technical difficulties of measuring the residual organic solvent,related structure impurities,water and inorganic element impurities were solved by the mass balance approach,and the accurate measurement methods of different impurities were established.4.Research on the traceability of quantitative nuclear magnetic resonance method:The difficulties of accurate measurement of volatile solvent by quantitative nuclear magnetic resonance method were conquered.The internal standard was optimized,and a patent of an accurate weighing and solution preparation method was established.Accurate assignment of the purity of TAME has been realized.5.Comprehensive evaluation of uncertainty:The uncertainty from the homogeneity,stability and measurement method was thoroughly investigated.The accuracy test of different methods was conducted.The purity of the TAME certified reference materials was 99.9%,and the expanded uncertainty was 0.3%(k=2). |
