Studies On Determination Of Trace Elements In Food By Hydride Generation-atomic Fluorescence Spectrometry

With the development of science and technology and the great exploitation of natural resources, the generous inorganic and organic compounds enter into our environment and result in catholicity contamination in water resource, atmosphere, soil and food et al,which caused safety problems of food.. Metal contamination has become a key item in global food pollution plan of UNDP/FAO/WHO.As a important product in Xinjiang Catsup is easy to make much foreign exchange. Due to distinct geographical environment, quality of Catsup in Xinjiang is internationally recognized and is better than that of American's, Italian's et al. Besides Xinjiang is one of the minority areas fitted to plant tomato and one of the three producing centers of tomatoes. The Catsup is popular in Japan, Northern American and European Union et al. But Catsup contains some heavy metals such as As, Hg, Pb and Sn et al, which have a certain or sometimes serious side effects. Metal will bring about serious harm to people if its residual in food went beyond the limits. Building effective detection technology of heavy metal in Catsup is an important measure to keep food safety. Meanwhile, it boosts Catsups' competition in international market. Major elements were selected as the study objectives in experiment, which have significant practical importance and value.Objective To establish a method for simultaneous determination of lead and arsenic,cadmium and m ercury in food samples atomic fluorescences pectrometry.Method Microwave-digestion technique using HNO3-H2O2 was applied for the pretreatment of samp le.This study was to optimize the conditions for single-element detection,and on the basis of it,we searched for the conditions of double-element measurement,in order to improve work efficiency and lower the analy-sis cost. We did the following work by using hydride generation atomic fluorescence spectrometry using in termittent flow system (AFS-9800) and microwave digestion systems.To perfect the detection conditions and increase detection sensitivity,we performed experiments to choosed the best pre-treatment methods,red-uctant concentration,instrument performance parameter,and counter-interference reagent.And Operation conditions such as acid medium, HCl concentration,carrier gas flow, Height of atomization,Negative high pressure and Lamp current on determination of heavy metal were diseussed. Through analyzing a large am-ount of data and test records, the high sensitive methods for arsenic, mercury, lead and tin have been estab-lished. And we explored the best conditions of double-element detection.Results Under the optimized conditions, the linear response ranges from 0.0μg/L-10.0μg/L for As and the linear response ranges from 0.0μg/L～1.0μg/L for Hg,arsenic were linear and the correlation coef-ficient was more than 0.9998. The relative standard deviation (RSD) was 0.9%.Mercury were linear and the correlation coefficient was 0.9999. The relative standard deviation was 1.2%.And the detection lim-its of 0.0122μg/L and 0.0015μg/L were obtained for As and Hg respectively.The linear ranges of lead in 0.0μg/L～10.0μg/L,Lead were linear and the correlation coefficient was 0.9997. The relative standard deviati-on was 1.66%. the detection limit of lead was 0.0023μg/L.The linear ranges of tin in 0.0μg/L～100.0μg/L,Tin linear and the correlation coefficients was 0.9997. The relative standard deviation of the analytical methods 1.05%. the detection limit of Tin was 0.0011μg/L.The proposed method was provided with linear response ranges from 0.0μg/L～10.0μg/L for As and 0.0μg/L～1.0μg/L for Hg,and the detection limits of 0.0029μg/L and 0.0075μg/L were obtained for As and Hg respectively.The precision is 0.38% and 0.25%(R.S.D.,n=11).The spiked recoveries were 94.2%-102.7% for arsenic, the mercury was from 90.66%～101.49%,94.61%～100.11 %for lead,,the tin recoveries was from 92.01%-99.08%. The spiked recoveries were 91.09%-100.43% and 93.06%-101.21% for arsenic and mercury.Conclusions As,Hg,Pb,Sn and As and Hg in the standard reference substances cabbage (GBW100-14)and spinach (GBW10015)were determined by this method and the results are in good agreement with c-ertified values.The method was convenient, rapid and accurate with satisfactory results. It has been applied to the determination of As in fructus mume.