Determination Of Cadmium With ICP-MS And Risk Evaluation Of Heavy Metal In Rice

Rice is the major food source in China,the quality and safety of rice is directly related to human health,and the problem of heavy metal pollution has become a focus.In this thesis,the contents of total Cadmium in rice from Foshan were determined using ICP-MS,and analyzed using an assessment of the uncertainty of determining the contents of total Cadmium in rice,the health risk of Cadmium in rice for different population were evaluated.The results are as follows.Different methods of pretreatment influence results to a certain extent.Themicrowave digestionis with advantages of high digestion ability and speed,of small loss,less pollution and lower reagent blank,and can be used for the measurement of microelement in the majority.The contents of total Cadmium and Lead in rice for 46 kinds and 138 samples from Foshan were determined using ICP-MS and digestion.This paper analyzes the precision,recovery rate,comparision of different instruments and different detectioninstitutions to determine the feasibility of the method for determining the cadmium content of rice from Foshan.The relative standard deviations for the metal content of the same sample using ICP-MS were 0 to 0.15%,which is less than 0.5%,with the recoveries as 94.00% to 100.90%,which meet the requirements of quality assurance.The content of heavy metal in different kind,different origin and different season of rice was determined and compared,the content of heavy metalis different obviously.The content of cadmium in rice was determined by inductively coupled plasma-mass spectrometry(ICP-MS)and graphite furnace atomic absorption spectrometry(AAS),the Samples was pretreatedby digestion,and the experiment of standard addition and determination of standard substancesat the same time.The results showed that the detectable limit of ICP-MS is a little higher than AAS,ICP-MS method had better linear correlation,and was more sensitive,simple,and accurate than graphite furnace atomicabsorption spectrometry.The results of determination indicate that the contents of total Cadmium in rice from Foshan meet the requirements of GB 2762-2012 and NY/T419-2014 in China.The method of ICP-MS for the determination of Cadmium in rice was evaluatedaccording to GB/T 5009.15-2014 and analyzed using an assessment of its uncertainty.Through various sources of measurement uncertainty analysis process,calculate uncertainty components,derived relative standard uncertainty of 0.1902 mg/kg,the expanded uncertainty was 0.01709 mg/kg(k=2),and the relative standard deviation was 8.99%,which was less than 20% according to GB/T 5009.15-2014,therefore,the uncertainty of the method was withinthe certified values.Through study on uncertainty measurement of Cadmium in rice using ICP-MS,it helps to improve the repeatability of test data as well as ensure the quality of test data.Accordingto the pollutionindex Evaluation,USEPA and the value of PTWI from WHO/FAO,the Evaluation on cadmium contamination in rice to human healthin Foshan was made.The results were same that the ricedetermined in Foshan was no health risk for people.However,the rice in Foshan was contaminated by certain amount of Cadmium,accordingto theUSEPA and the value of PTWI from WHO/FAO.The health risk was low.But the government still should continue to take effective measures to prevent the Cadmium contamination in rice and make sure that the rice in the markets is safe and not overproof.