Evaluation of quantitative synchrotron radiation micro-X-ray fluorescence in rice grain

Abstract

Concentrations of nutrients and contaminants in rice grain affect human health, specifically through the localization and chemical form of elements. Methods to spatially quantify the concentration and speciation of elements are needed to protect human health and characterize elemental homeostasis in plants. Here, an evaluation was carried out using quantitative synchrotron radiation microprobe X-ray fluorescence (SR-µXRF) imaging by comparing average rice grain concentrations of As, Cu, K, Mn, P, S and Zn measured with rice grain concentrations from acid digestion and ICP-MS analysis for 50 grain samples. Better agreement was found between the two methods for high-Z elements. Regression fits between the two methods allowed quantitative concentration maps of the measured elements. These maps revealed that most elements were concentrated in the bran, although S and Zn permeated into the endosperm. Arsenic was highest in the ovular vascular trace (OVT), with concentrations approaching 100 mg kg−1 in the OVT of a grain from a rice plant grown in As-contaminated soil. Quantitative SR-µXRF is a useful approach for comparison across multiple studies but requires careful consideration of sample preparation and beamline characteristics.

High Resolution 3D Strain and Orientation Mapping within a Grain of a Directed Energy Deposition Laser Additively Manufactured Superalloy

“…The band-like structures aligned across the length of the grain show ≈ 0.3-0.5°misorientation from one another, while in the interior they consist of cells with diameters <5 µm. and ∆χ are the differences between the local sample tilt center-of-mass and their grain averages [24]. Figure 2(c) and (d) show ≈5 µm-sized subgrains having boundaries with high dislocation densities at a layer 3 µm deep below the surface of the grain.…”

“…The orientation and strain maps were collected as 2D meshes of the sample tilts and the 2θ around the 111 scattering vector (Figure 2(a)). The DFXM data were analyzed using the darfix and inhouse built MATLAB scripts [24]. The matching of the GOI for EBSD and DFXM measurements was enabled by a DCT scan on the sample (see the Supp.…”