Portable x-ray fluorescence for assessing trace elements in rice and rice products: Comparison with inductively coupled plasma-mass spectrometry

Portable x-ray fluorescence (XRF) was investigated as a means of assessing trace elements in rice and rice products. Using five measurement trials of 180 s real time, portable XRF was first used to detect arsenic (As), manganese (Mn), iron (Fe), nickel (Ni), copper (Cu), and zinc (Zn) in a variety of rice samples. The same samples were then microwave-digested and used to determine elemental concentrations using inductively coupled plasma-mass spectrometry (ICP-MS). The concentrations of As, Mn, Fe, Cu, and Zn determined by ICP-MS were found to be consistent with other recent studies involving various types of rice and rice products. When assessing for As, Mn, Fe, Cu, and Zn, comparison of results between XRF amplitude and ICP-MS concentration (wet weight) demonstrated a linear relationship with a significant correlation. A significant correlation between XRF amplitude and ICP-MS concentration was not found when assessing for Ni.