Multielemental Analysis in Rice Grains by Total Reflection X‐Ray Fluorescence

ABSTRACT Rice ( Oryza sativa ) is a staple food cultivated worldwide and represents a significant source of essential nutrients for humans. However, this cereal may also contain potentially toxic elements including chromium, arsenic, and lead typically present at trace concentrations (ng.g −1 ). The quantitative determination of these elements is analytically challenging due to their low concentrations within the matrix. Several analytical techniques are commonly employed for elemental quantification, notably inductively coupled plasma mass spectrometry (ICP‐MS), X‐ray fluorescence (XRF), and atomic absorption spectrometry (AAS). Among XRF‐based approaches, total reflection X‐ray fluorescence (TXRF) has proven particularly effective for trace element analysis. In the present study, elemental concentrations were determined in 28 rice samples categorized into seven groups: white, parboiled white, brown, parboiled brown, red, black, and wild. Analyses were conducted using TXRF with a Bruker S2 PICOFOX spectrometer. Concentrations of K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Br, As, and Rb were measured and compared with literature data. The results revealed that black, red, and wild rice varieties exhibited higher concentrations of K, Ca, Cu, and Zn relative to white rice varieties. Wild rice showed the highest levels of Zn (53.2 μg.g −1 ) and Cu (8.6 μg.g −1 ). Regarding arsenic, brown rice (BRW) and red rice (RED) samples displayed the highest concentrations, exceeding the maximum permissible limits established by ANVISA and WHO. The data obtained expand the current understanding of the elemental composition of rice commercialized in Brazil and underscore the importance of monitoring toxic elements in grains widely consumed in the human diet.