The Assay Technique Research Of High-precision X-ray Fluorescence Instrument Detection Limit

Currently, X fluorescence analysis technique has been widely used in environmental monitoring, prospecting, and industrial production. With the increasing application requirements, performance requirements for the instrument is gradually improving.The detection limit is one important indicator to judge the test and analysis performance of the instrument, especially for trace analysis instruments.Because of the aging of interior device will change detection limit of the instrument. Therefore, it need to regular test the instrument detection limits. The research reports of High-Precision portable X-ray fluorescence instrument detection limits still rare.This article subject Supported by National High Technology Research and Development Program of China: high precision spectrum detection instrument development（No.2012AA061803）.It aims to combine experimental methods to study the measurement techniques of Portable X-ray fluorescence analyzer detection limit.And respectively SiO₂ and polyethylene（PE） as the matrix, detects analysis detection limitof this severalelementsTi, Cu, As, Pb, Mo, Ag in IED-2000 T portable X-ray fluorescence instrument.And has made the main achievements asfollows.1.Confirmed the optimal working conditions of the instrument in different modes.In medium elements mode,the optimum tube voltage is 24kV; the optimum tube current is 30μA. In heavy elements mode,optimum tube voltage is 40kV; the optimum tube current of 1μA;2.Respectively SiO₂ and polyethylene（PE） as the matrix, preparation a series of standard sample with low content,These provides a basic condition for conducting the detection limit research and the instrument’s detection testing in the future. After testing, the samples have good uniformity（the relative error of each element distribution < 2%）;3. When SiO₂ as matrix, the measured Ti, Cu, As, Pb, Mo, Ag detection limits Respectively were（unit: μg/g）:73.7, 8.0, 11.2, 68.0, 8.7, 68.2;When PE as matrix, the measured Ti, Cu, As, Pb, Mo, Ag detection limits Respectively were（unit: μg/g）: 35.6, 3.1, 5.7, 48.8, 7.1, 27.1;Research shows that, X-ray fluorescence analyzer detection limits are closely related with sample matrix components, the type of target elements, measuring time, X-ray tube working conditions etc.. And it changed greatly, therefore, in practical work should attract attention.