Study On The Preparation And Detection Technology Of Food Grade Carbon Dioxide Gas Reference Material

The quality of food grade carbon dioxide has closely related with people's health, so it is particularly important to strictly control impurities in carbon dioxide products.Our country has promulgated some national standards in the related field, but most national reference materials referred to standards are blank, which leads to the defects of value traceability and transmission. Meanwhile, the sources of food grade carbon dioxide are wide, and it has different component content and uneven purification levels, which directly affects the quality of subsequent food production. In such circulations, the research on the preparation and detection technology of trace components in food grade carbon dioxide gas reference material has great significance in maintaining the strict quality control of food additives carbon dioxide and unifying national testing standards.Specific research results are as follows:1.C2H5OH/CO2,C6H6/CO2,H2S/CO2,SO2/CO2, COS/CO2, O2/CO2, C2H3Cl/CO2 gas reference materials were prepared by gravimetric method.In the preparation process, the adsorptions of ethanol,benzene, and sulfides by cylinders were investigated. The effect of cylinder adsorption can be ignored by using pre-saturation and pre-treated technique.2.Through the optimization experiment, optimum gas chromatographic methods with high precision and close linearity were determinated, RSD were all less than 1.3%,liner correlation coeffieients were all more than 0.9992.3.The mixing experiment and comparison consistency inspection of these seven gas reference materials were investigated, and the experiment of reproducibility, value stability over time and under different pressure of the first five substances were studied. The experimental results are good.4.The uncertainty evaluation of gravimetric preparation and value stability over time indicated that relative expanded uncertainty of the first five substances were all less than 2%. These five gas mixtures have been approved as the grade secondary reference materials by AQSIQ.