Analysis Of Trace Elements In Animal Feed

Feed is an important source of sufficient nutrients for animals.It will seriously affect the growth and the quality of livestock,and then affect human health.If the necessary trace elements are excessive or insufficient in the feed.Therefore,the content and proportion of various trace elements in feed should be controlled within a strict range.It is particularly important to analyze and determine the composition and content of trace elements in various feed materials,compound feed,premix and mineral feed additives.This paper is based on Spectrophotometry,Atomic Absorption Spectrometry and ICP-AES to check the trace elements in animal feed.The details are as follows:(1)A Spectrophotometry method was established for quantitative analysis of Trace Zinc in animal feed with PAN-Zn Chromogenic System.The results showed that Zn and PAN formed an orange-red complex in weak acidic medium(p H=6).The red complex had the maximum absorption at 590 nm.When the solution was colored and solubilized by adding ethanol.And,the relationship about Zn and the concentration was linear,when the concentration was 0~0.7 ?g/m L.The linear correlation coefficient was 0.9998,the recovery rate was 97.8%~102.9% and RSD was 1.79%.This method had good precision and accuracy.(2)The feed samples were digested by incomplete digestion method and the contents of Cu,Fe and Mn were determined by flame atomic absorption spectrometry.The results showed that the linear range of the method was 0~4.00 g/m L,the recovery was 93.8%~101.9% and RSD was 1.40%~3.79%.The amount of digestive reagent is small and the relative error is less than ±1%.This method is accurate,simple,time-consuming compared that of dry ashing method.The concordant results were obtained by using two different pretreatment procedures.Therefore,it is feasible the non-complete digestion method to replace the dry ashing method.(3)The feed samples were digested by microwave digestion and the chromium in feed was determined by graphite furnace atomic absorption spectrometry.The influence factors of matrix modifier,ashing temperature and atomization temperature on the determination results were studied,and the optimum experimental conditions were determined.The results showed that the relationship about Cr and the concentration was linear,when the concentration was 0~15 ?g/L.The linear correlation coefficient was 0.9987,the recovery was 98.2%~103.1%,the relative standard deviation was 2.35%.The method had good precision and accuracy.(4)A method for the determination of Pb,Al,Sr,Ba,Co,Ni and Se in feed by ICP-AES with microwave digestion for sample pretreatment was developed.The method has good precision and accuracy,and can be used for simultaneous determination of trace elements in feed.