Study on the method of using ICP-MS to determine microelements in the animal feed

The method for the determination of microelements such as Cu, Zn, Fe, Mn, Cr, Cd, Pb, As and Se in the animal feed by inductively coupled plasma-mass spectrometry was developed. The operation parameters, spectrum interference, matrix effect and memorial effect were studied in detail. Under optimal condition, the detection limits of these nine elements were from 2.03 x 10(-3) to 3.17 mu g . L-1, and the linear range was over three orders with a correlation coefficient above 0.999. This method was applied directly to determine microelements in real samples involving the standard wheat powder, formular feed and pre-mix feed. The determination results of microelements in the standard wheat powder accorded with reference results. The recovery of microelements in the formular feed was from 86% to 115%, and the relative standard deviations <= 8.2% (n=6). The results of elements content in the pre-mix feed were identical with those determined by national standard method. This method is simple, sensitive, accurate and can perform simultaneous multi-elements determination compared with conventional method of animal feed determination. The results were satisfactory.