Pretreatment Method And Analysis For Determination Of Nitrobenzenes In Edible Tissues Of Fish, Domestic Animals And Poultry

In this experiment we contrast four kinds of extraction pretreatment methods, which are separately Soxhlet, Supersonic, Homogenization and Steam distillation. Meanwhile, through the returns-ratio, we make an objective appraisal of the four methods, in which the returns-ratio of Soxhlet extraction method is the highest, the returns-ratio of Homogenization extraction method is a bit lower---about 77% and the returns-ratio of supersonic method and the steam distillation is the lowest--- 70% or so. However, the procedure of Soxhlet extraction method is Homogenization and time-consuming, while Homogenization extraction method is easy to operate and the procedure can be done much more quickly; besides, the amount of the solvent used is fewer. What's more, the returns-ratio of Homogenization extraction method is lower than that of Soxhlet extraction method. Therefore, we draw up a plan to establish the Homogenization extraction method, a pretreatment method to extract nitrobenzene from the edible tissues of fish, domestic animals and poultry. We also optimize the Homogenization pretreatment method through the orthogonal experiment in order to obtain a result of higher returns-ratio.Homogenization optimization experiment is an orthogonal experiment of three factors and three horizontal. We examine the influence factors of the returns-ratio on the basis of three factors: the time of Homogenization, the type of extracting solvent and the amount of Al2O3 which is filled in decontamination center. To conclude, we can draw a conclusion that the type of solvent has the greatest effects on returns-ratio and we can get the best extracting result on these conditions: Firstly, the best extracting solvent is mixed solvent of acetone and hexane. Secondly, the time of Homogenization is 1 minute. Thirdly, the amount of Al2O3 which is filled in decontamination center is 4g. We examined the optimization method through adding-sign experiment and the result of the experiment shows that the returns-ratio is 87.2%-92.8% on the condition of orthogonal experiment, the average returns-ratio is 89.85%, and the RSD is smaller than 3%. So we can say that the experiment is a certain feasibility.In this experiment, we also determined some samples of fish and poultry which come from the polluted water and areas in Songhua River by using Homogenization extraction method. Referring to the national standard that the maximum examination limit of nitrobenzene in waters is 17ug/L, we got the result of this experiment---nitrobenzene were found in some samples but the amount of nitrobenzene in all of the samples were lower than the limit.