A Research On The Determination Of Total Arsenic In Sea Food By AFS And ICP-MS

Total arsenic in the sea food includes organic and inorganic arsenic,which has complex existing form.Organic arsenic is hardly to be translated into inorganic arsenic completely in the digestive process.The method which measures the total arsenic in food from Chinese standard?GB?is not suitable for the sea food.Moreover the method wastes more time and reagent,maybe leads to low result,even undetected.This paper optimizes the pretreatment and instrument condition base on Chinese standard?GB?.Firstly this paper researched on the optimization procedure of wet digestion and AFS conditions.And it built the optimum determination method of total arsenic content in sea food.That was wet-digestion –AFS.It optimized the conditions: proportion of acid system,mode of heating,storage time under room temperature,etc.And then we gained the best optimum condition of wet digestion:adding 20 mL HNO₃+HClO₄?4+1?and 1.25 mL H2SO4,covering small funnel,heating on hot plate 0.5 h and then moving to electric furnace to continue digestion,storing 20 min under room temperature,measured by AFS.The optimum instrument conditions of AFS: 1% KBH4,5% HCl,8 mm atomizer height.The sample pretreated and detected with the building method just needed 1.5 h.It could save more time and reagent,reduced detection limit?0.004 mg/kg?.The detection result on the fish and scallop meal were accurate,reliable,1.8% and 2.6% RSD respectively,94%¹02% recovery.The result showed that the method had good linear relationship,high sensitivity,strongly repeatability.The detection method of total arsenic can detect sea food in large quantities.Secondly this paper researched on the optimization procedure of microwave digestion and ICP-MS conditions.Then we built the optimum determination method of microwave digestion ICP-MS.We gained the best optimum condition: HNO₃ and H₂O₂ acid system,5:2 proportion,standing 1 h before digestion,driving to leave 0.5 mL acid solution,Rh and In correction.The quantitative determination of total arsenic by microwave digestion ICP-MS had a satisfactory result,0.015 mg/kg detection limit,1.2% RSD,95% recovery,highly accuracy,full automation,economize on manpower.The inadequacy was that the whole process consumed 5 h,and was not suitable for detecting sample in large quantities.At the same time,we compared the detection results of ICP-MS and AFS.We found that microwave digestion AFS not worked well.The detecting result was low and inaccuracy.Finally,this paper researched the determination result of marine fishes,crustaceans,mollush,from wet-digestion-AFS and microwave-digestion-ICP-MS.They got the same results basically.Relative differences were less than 10%.We knew that these two methods all can be used for detecting sea food.They provided determination method for detecting sea food for next work.At the same time we analysed the residues of total arsenic from different kinds of sea food on Xiamen markets.The acquisition samples had high content of total arsenic,mostly higher than the limit.But we knew just only inorganic arsenic had toxic action.It could infer that the samples had not out of GB limits,which were all kept within safe range.