Simultaneous Determination Of Multi-Elements In Infant Milk Powder

Infant formula is one of the world's most stringent food production management,from these products in the accurate determination of the added element content is essential.Therefore,to strengthen the international technical exchanges and cooperation,the establishment of infant formula milk powder analysis methods and mutual verification,to improve our laboratory testing and testing capabilities,so that our detection level out of the country,to the international level has long-term and important significance.(1)In this experiment,the differences in the digestion results caused by the difference in volume difference between nitric acid and hydrogen peroxide were compared.Finally,5mL nitric acid and 1mL hydrogen peroxide was used to digest the samples.At the same time,according to the nitric acid and hydrogen peroxide of different manufacturers Reagent blank on the determination of the results of the final selection of Merck's nitric acid and Sinopharm Group of excellent pure hydrogen peroxide.(2)In this experiment,we studied the effects of different temperature on different elements.Microwave digestion was carried out from 120? to 200?.All the elements were dissolved in the range of 160? to 200?.Therefore,The microwave digestion temperature was set at 200?.At the same time,the effects of different digestion time on the determination results were studied.The results showed that the samples were completely decomposed and then completely digested for 20 to 25 minutes,and no obvious granules appeared,and the liquid was clear and transparent.There was no significant difference between the two.To shorten the measurement time,select the digestion time of 20min.(3)In order to increase the sensitivity of selenium,the alcohol was added in the pretreatment process and the effects of methanol,ethanol and isopropanol were studied.The effects of volatile and safety were determined.The methanol was added at the same time to analyze the relationship between methanol content and selenium sensitivity.When the concentration of methanol was 2%-4%,the sensitivity was the highest.In order to select as few organic reagents as possible,2%methanol was used in the experiment.(4)In this experiment,we used mass spectrometry dynamic reaction pool technology to remove the interference,study the different reaction gas flow on the sensitivity of different elements,and finally determine the reaction gas flow conditions.(5)In this study,the new analytical methods were verified:the detection limit was 2.0-2000?g · kg-1 the relative standard deviations were less than 5%,the recoveries were 93.2%-103.6%,the linear correlation coefficient was 0.9993-1.0000,Meet the requirements.(6)In this study,10 kinds of infant formula milk powder at home and abroad were selected and the results were consistent with the results of national standard method.It also validates that the established method has good adaptability to different samples...