Simple procedure for nutrient analysis of coffee plant with energy dispersive X-ray fluorescence spectrometry (EDXRF)

Nutrient analysis is used to estimate nutrient content of crop plants to manage fertilizer application for sustained crop production. Direct solid analysis of agricultural and environmental samples by energy dispersive X-ray fluorescence spectrometry (EDXRF) was chosen as alternative technique to evaluate the simultaneous multielemental quantification of the most important essential elements in coffee (Coffea arabica L.) plants. Inductively coupled plasma atomic emission spectrometry and certified reference materials made from leaves were used to calibrate and check the trueness of EDXRF method for the determination of the concentration of several nutrients in coffee leaves and branches. Fluorescence spectrometry proved to be advantageous and presented low cost as loose powder samples could be used. Samples collected from a field experiment where coffee plants were treated with excess of Ni and Zn were used to verify the practical application of the method. Good relationships were achieved between certified values and data obtained by EDXRF, with recoveries ranging from 82 to 117 %

Multi-elemental composition of Slovenian milk: analytical approach and geographical origin determination

The main objective in multi-elemental analysis in food is to obtain the best results in the shortest time and with minimal contamination and reagent consumption. Three different methods were investigated in the present study to obtain the elemental content in milk samples: energy dispersive X-ray fluorescence spectrometry (EDXRF), k&lt;sub&gt;0&lt;/sub&gt;-instrumental nuclear activation analysis (k&lt;sub&gt;0&lt;/sub&gt;-INAA) and the inductively coupled plasma mass spectrometry (ICP-MS). Quality assurance including intercomparison exercises of these measurements proved entirely satisfactory and was typical of that previously established for this technique. It was found that EDXRF was the cheapest, simplest and environmental friendly method for analysis of multi-elemental composition (P, S, Cl, K, Ca, Zn, Br, Rb, Sr) in milk samples, while for determination of Mn, Fe, Cu, Se content and possible identification of pollutants such as As, Cd and Pb ICP-MS was a method of choice due to its excellent sensitivity and accuracy. These two methods were also used to determine the multi-elemental composition in Slovenian raw cow milk from different geographical regions: Alpine, Mediterranean. Dinaric and Panoninan in December 2013. Linear discriminant analysis (LDA) was used to explore multi-elemental analysis of milk samples to obtain classification according to geographical regions. Regional discrimination was most successful taking into account Ca, S, P, K, and Cl with prediction ability of 66.7%.</jats:p

Magnetic carbon nanocomposites via the graphitization of glucose and their induction heating

Carbon nanocomposites containing iron-based nanoparticles are attractive materials for the catalyst sup-ports used for magnetic (induction) heating catalysis. The metallic, soft-magnetic iron nanoparticles pro-vide local heating of the support in an alternating magnetic field and ensure rapid magnetic separation of the nanocomposite particles from reaction suspensions. In this work, magnetic carbon nanocomposites were prepared by annealing the precursor particles consisting of iron-oxide nanoparticles dispersed in a carbohydrate matrix. The annealing was conducted at 600 degrees C and 750 degrees C in an Ar atmosphere. At both temperatures the carbothermal reduction of iron oxide to Fe/Fe3C was observed; however, at the lower temperature the rate of reduction and the growth of the nanoparticles were considerably slower. The Fe3C was formed in negligible amounts only after a prolonged period of annealing at 600 degrees C. A detailed structural analysis showed that the Fe/Fe3C nanoparticles catalyze the graphitization of the carbonaceous precursor material already at 600 degrees C, resulting in the formation of a graphitic shell that surrounds them. This shell is tight enough to prevent the areal oxidation of the encapsulated Fe nanoparticles; their magnetic properties remained unchanged even after 1 year of storage under ambient conditions. At the higher annealing temperature, the growth of the Fe/Fe3C nanoparticles caused bursting of the graphitic shell and thus par-tially exposed their surfaces to the atmosphere. All the nanocomposites exhibited ferromagnetic behavior in accordance with their compositions. The nanocomposite that was predominantly composed of a graphitic shell, encapsulated Fe nanoparticles and a negligible amount of Fe3C, showed the highest specific ab-sorption rate (760 W/gFe at 274 kHz), even at a relatively low AC-field amplitude (88 mT).(c) 2023 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/)

Radiological characterization of alkali-activated material doped with Sm2O3 and its polymerization products

The aim of this study was determination of radiological characterization of alkali-activated material with Sm2O3 and its polymerization products. Alkali-activated materials with 1 wt.% and 5 wt.% addition of Sm2O3 were synthesized and their natural radioactivity was determined. Energy dispersive X-ray fluorescence showed changes in the phase composition, or the formation of stable compounds, at higher temperatures. All samples demonstrated good pozzolanic activity, while the percentage of Sm2O3 was slightly changed. The X-ray photoelectron spectroscopy confirmed that the obtained material has a very low carbon content making it environmentally friendly, due to its low carbon content. A detailed analysis of the oxygen peak indicates variations in the stoichiometry of the oxides, which may affect the changes of natural radioactivity. Scanning electron microscopy confirmed that with the increase in the temperature of the thermal treatment, the opening of the pores in the alkali-activated material occurs, as well as further propagation of reaction that increased porosity and crystallization. Radiological measurement confirmed that examined alkali-activated material is safe for usage and exploitation. It should be emphasized that the presence of artificial radionuclide cesium 137Cs was not detected