Improvement And Application Of Detection Methods For Heavy Metals In Fish

To improve the detection accuracy of heavy metals mercury,cadmium,arsenic and lead in fish,and to save detection reagents and shorten the detection period,the optimal detection conditions for each heavy metal were investigated in referring to the national standard method.Based on obtaining the value range of each factors by the single factor experiment,response surface method was adopted to design the experiment plan and optimize the the detection conditions.The specific optimal detection conditions for each heavy metal in fish are as follows:(1)The detection conditions of mercury in fish were optimized.The acid extraction and digestion temperature,hydrogen peroxide and potassium borohydride dosage during the pretreatment of mercury in fish were taken as factors.Based on obtaining the value range of these factors,the response surface experiment plan was designed and performed.The optimization results showed that the recovery rate of mercury was the highest when the acid extraction temperature was 88.4 ?,the digestion temperature was 171.7 ?,the amount of hydrogen peroxide assisted digestion was 1.2 mL,and the concentration of potassium borohydride was 13.4 g/L.With this detection conditions,the recovery rate of mercury is98.9 %.The error between the determined recovery rate and the predicted is-3.69 %.(2)The detection conditions of cadmium in fish were optimized.The acid extraction temperature,hydrogen peroxide amount,ammonium dihydrogen phosphate concentration and addition amount of matrix modifier,ashing temperature and atomization temperature in the pretreatment process of heavy metal cadmium in fish were taken as factors.Based on obtaining the value range of these factors,the response surface experiment plan was designed and performed.The optimization results showed that the recovery rate of cadmium was the acid extraction temperature was 130 ?,the proportion of hydrogen peroxide assisted digestion was 17.8 %,the concentration of ammonium dihydrogen phosphate was 10.5 g/L,the addition amount of ammonium dihydrogen phosphate to the matrix improvement agent was 5.5 L,the ash temperature was 700 ?,and the atomization temperature was 1800?.With this detection conditions,the recovery rate of cadmium is 97.5 %.The error between the determined recovery rate and the predicted is-1.14 %.(3)The detection conditions of heavy metals arsenic in fish were optimized.The concentration of thiocarbamide,ascorbic acid,thiocarbamide + ascorbic acid as well as potassium borohydride and fluid-carrying hydrochloric acid in the fish during the pretreatment of heavy metal arsenic were taken as factors.Based on obtaining the value range of these factors,the response surface experiment plan was designed and performed.The optimization results showed that the recovery rate of arsenic was the highest at the concentration of thiocarbamide 100 g/L,ascorbic acid 100 g/L,thiocarbamide + ascorbic acid3 mL,potassium borohydride 10 g/L and hydrochloric acid 2 %.With this detection conditions,the recovery rate of arsenic is 96.5 %.The error between the determined recovery rate and the predicted is 0.56 %.(4)The detection conditions of heavy metal lead in fish were optimized.The acid removal temperature,the amount of hydrogen peroxide and the atomization temperature of the assistive reagent were taken as factors.Based on obtaining the value range of these factors,the response surface experiment plan was designed and performed.The optimization results showed that the recovery rate of lead was the highest when the acid extraction temperature was 160 ?,the dosage of hydrogen peroxide assisted digestion was 1.5 mL and the atomization temperature was 2200 ?.With this detection conditions,the recovery rate of lead is 94.5 %.The error between the determined recovery rate and the predicted is 0.72 %.In short,the detection accuracy of heavy metals in fish was greatly improved with the optimized detection conditions.