Energy Dispersive X-ray Fluorescence Set-up Research Articles

Distribution of toxic elements in teeth treated with amalgam using μ-energy dispersive X-ray fluorescence

Over the years, the presence of mercury in amalgam fillings has raised some safety concerns. Amalgam is one of the most commonly used tooth fillings and contains approximately 50% of elemental mercury and 50% of other metals, mostly silver, tin and copper. Amalgam can release small amounts of mercury vapor over time, and patients can absorb these vapors by inhaling or ingesting them. In this study, 10 human teeth treated with dental amalgam were analyzed using energy dispersive X-ray fluorescence (EDXRF) to study the diffusion of its constituents, Ag, Cu, Sn and Hg. The used EDXRF setup, makes use of a polycapillary lens to focus radiation up to 25μm allowing the mapping of the elemental distribution in the samples. Quantification was performed using the inbuilt software based on the Fundamental Parameters method for bulk samples, considering a hydroxyapatite matrix.The teeth were longitudinally cut and each slice was scanned from the surface enamel to the inner region (dentin and pulp cavity). Mercury concentration profiles show strong levels of this element close to the amalgam region, decreasing significantly in the dentin, and increasing again up to 40,000μg·g−1 in the cavity were the pulp used to exist when the tooth was vital.

Relative K X-ray energy shifts in Fe, Cu and Zn metals and their compounds with EDXRF set-up

Energy Dispersive X-ray Fluorescence (EDXRF) set-up comprising low power X-ray tube and Si(PIN) detector has been used for chemical shift measurements in X-ray energies following a statistical method that involves division of measurement time into sub-divisions and in each sub-division the XRF spectra of element and its compound have been recorded. A polynomial fit to the photo-peak energies of recorded spectra determines the non-statistical fluctuations of the data due to instability of apparatus and environmental factors. Afterwards, the data was corrected for non-statistical errors. The method has been used for shift measurements in K X-ray energies of 8 pairs of 3 metals Fe, Cu and Zn; Fe and FeSO4·7H2O, Fe and FeS, Fe and Fe(NO3)3·9H2O, Cu and CuO, Cu and CuCl2, Cu and CuSO4·5H2O, Zn and ZnS and Zn and ZnBr2. The t-test for statistical significance of final results clearly supported the reliability of these shift measurements.

ED-XRF spectrometry-based trace element composition of genetically engineered rhizoclones vis-à-vis natural roots of a multi-medicinal plant, butterfly pea (Clitoria ternatea L.)

The energy dispersive X-ray fluorescence set-up incorporating a molybdenum secondary exciter was used for quantitative determination of major and minor elements in genetically transformed root somaclones (rhizoclones) of butterfly pea (Clitoria ternatea L.) which had been established via explant co-cultivation with Agrobacterium rhizogenes. The multi-elemental composition of these transformed rhizoclones was compared with that of the naturally grown in vivo donor plant. Trace elements namely Cr, Mn, Fe, Co, Ni, Cu, Zn, Se, Rb, Sr and Pb in addition to two macro-elements K and Ca were identified and quantified in root tissues of both sources. The elemental content of transformed root cultures was found to be at par with that of the natural roots of in vivo grown plants of the same species. These findings are implicated on the context of utilization of such Agrobacterium-mediated genetically transformed root cultures as a viable alternative to natural roots, the former being a fast-proliferating renewable resource of medicinally useful minerals essential for designing of effective drugs, besides providing an ex situ means for plant conservation.

L x-ray production cross sections in Th and U at 17.8,25.8 and 46.9 keV photon energies

The L x-ray production (XRP) differential cross sections in Thand U have been measured at the 17.8 keV incident photon energy(E_L3<Einc<E_L2, ELi is the Lisubshell ionization threshold) in an angular range90°-160°, and at the 25.8 and 46.9 keV incident photonenergies (E_L1<Einc<EK) at an angle of130°. The measurements were performed using the energydispersive x-ray fluorescence set-up in secondary excitationmode. In contrast to the findings of an earlier experiment (Sharmaand Allawadhi 1999 J. Phys. B: At. Mol. Opt. Phys. 32 2343), the present measurementsrule out the possibility of a strong angular dependence ofdifferential cross sections for various L3 subshell x-raysfollowing selective photoionization of the L3 subshell.Integral L XRP cross sections at the 17.8, 25.8 and 46.9 keVphoton energies, deduced assuming isotropic emission of the Lx-rays, are found to be in good agreement with those evaluatedusing the most reliable theoretical values of Li(i = 1,2,3) subshell photoionization cross sections,fluorescence yields, x-ray emission rates and Coster-Kronigtransition probabilities.