Preparation And Performance Study On Reference Materials Of Seven Kinds Of Benzene Series Solution

The benzene series mainly include benzene, toluene, ethylbenzene, o-xylene, m-etaxylene and p-araxylene, which were used in many organic and chemical industry widely. The benzene series have spread into the environment through various ways easily, causing serious environmental pollution in water, soil and air. In recent years, more and more attention has been paid to environmental protection, and the benzene series have turned out to be the key regulatory objects due to its serious pollution in water, soil, air and other fields. With the development of the detection frequency and quantity, reference materials of the high quality need to ensure the traceability and accuracy of metrical data inevitable.At present, the existing reference materials of benzene series unable to meet the needs of society due to single research methods, low accuracy or less purity. The study carried out seven kinds of benzene series on the basis of a large number of research, which covered basic application range of the benzene series. The study not only has used the long term applicabable analysis methods including GC-MS, GC, HPLC, but also has used new technology like NMR which has been developed in recent years.The qualitative analysis of the raw material of benzene and toluene have been conducted by GC-MS at first, and then the purity of benzene was certified to be 99.94% by GC and HPLC. At the same time, the qualitative analysis of the raw material of six kinds of benzene series have been determined by GC-MS and NMR, and then the certified value have been studied by GC. The final certified value of six kinds of benzene series were 99.97%, 99.94%,99.56%,99.40%,99.82%,99.85%. The solution of seven kinds of products have been prepared by weight capacity method included GC, HPLC and moisture contenet measurement, and then followed by the assessment of homogeneity, stability. The result showed that their homogeneity was good according to F-test and their stability met the Measurement Technical Norm which have been tested over one year.The standard density of seven kinds of products were 5.00 mg/mL,0.986 mg/mL,1.03 mg/mL,0.998 mg/mL,1.00 mg/mL,0.980 mg/mL,1.00 mg/mL. The solution of benzene in toluene of relative expanded uncertainty caused in the whole producing processes, the homogeneity test, stability test and other factors was 2.0%(k=2). The relative expanded uncertainties of six kinds of benzene series dissolved in methanol solution were 4.0%(k=2).Compared COMAR with NCRM, the results indicated that the seven kinds of the reference materials of quantity value were closed to the similar reference materials which have been prepared by China Institute of Metrology. The reference materials of seven kinds of benzene series solution are accurate and reliable from environmental monitoring users’s feedback.