Preparation of the In‐House Reference Materials of the Food Grain Sample for <scp>XRF</scp> Analysis

ABSTRACT A simple and quick method for preparing the in‐house reference materials of food grain samples for XRF analysis was developed for the determination of Cr, Fe, Mn, Cd, and Pb. The reference materials were prepared by mixing wheat flour or potato starch powder with a toluene solution of organometallic compounds as a standard. The mixture was pressed into a cylindrical pellet and measured by XRF analysis. The prepared food samples had a homogeneous elemental distribution. Calibration curves of five elements showed a good linearity in the calibration ranges. The lower limits of detection (3σ) were 0.09 mg/kg for Cd, 0.06 mg/kg for Pb, 0.04 mg/kg for Fe, 0.06 mg/kg for Mn, and 0.07 mg/kg for Cr, respectively. The slopes of the calibration curve for the five elements in the reference sample made by wheat flour and potato starch as a matrix agreed well. The quantitative values of analytes were in good agreement with the certified values of the food certified reference materials (CRMs).