Multi-elemental analysis by energy dispersion X-ray fluorescence spectrometry and its application on the traceability of soybean origin

Abstract

In this work, a commercial energy dispersion X-ray fluorescence (ED-XRF) spectrometer was utilized to measure the trace elements in soybean samples. After optimizing the radiation time and calibration strategy, ED-XRF was able to successfully measure 9 elements (Mg, K, Ca, Mn, Fe, Ni, Cu, Zn, and Rb) in 296 soybean samples from five producing areas of northern China (Henan, Inner Mongolia, Xinjiang, Heilongjiang, and Liaoning). Since principal component analysis (PCA) is not able to distinguish all growing areas completely, the multi-layer perceptron (MLP) procedure was employed which demonstrated to have a powerful classification capacity with an accuracy rate of 96.2%. XRF is a type of solid sampling analytical method, which is fast, accurate and partly portable for multi-elemental analysis. The combination of MLP and ED-XRF overcomes the analytical disadvantages found with ICP-MS or wavelength dispersion XRF analysis, and provides a novel and fast testing method for on-site recognition of food origin traceability.