Radioisotope-induced X-ray Fluorescence Research Articles

An X-Ray Fluorescence and Principal Component Analysis study of pottery from Orraon

Radioisotope-induced X-ray fluorescence XRF was used to determine the composition of 64 pottery sherds recovered from the settlement of ancient Orraon, northwestern Greece. The XRF data were submitted to Principal components analysis PCA and distinct sample clusters were identified, originating from differences in major and trace elements concentrations. The statistical classification, combined with archaeological criteria, allows conclusions related to the raw materials and paste recipes used in pottery manufacturing. Distinction between local production and imported pottery may also be inferred.

The In-Vivo Co-monitoring of Protein, Polymeric Delivery System, and Spectator Ions by Radioisotope Induced X-Ray Fluorescence

Abstract The subcutaneous delivery of iodinated bovine serum albumin (I-BSA) incorporated into a barium alginate hydrogel matrix, synthesized from barium bromide, was monitored in vivo by radioisotope-induced X-ray fluorescence. By measuring the iodine, barium, and bromine X-ray fluorescence signals, we were able to simultaneously monitor the status of an entrapped protein, the hydrogel delivery device, and the spectator ions in the hydrogel. The release of the labeled protein followed first-order kinetics with half-lives of 6 h for the I-BSA in phosphate buffer solution up to 28 h for the I-BSA incorporated in the alginate hydrogel. The degradation of the barium alginate hydrogel was biphasic, and the disappearance of the bromide spectator ion from the hydrogel was well described by Fickian diffusion.

Identification of lead in metal food can seams using 57Co RXRFS

Radioisotope-induced X-ray fluorescence spectrometry procedures developedfor screening solder for Pb are described. By using 57 Co as an excitationsource, food cans with Pb-soldered seams were easily distinguished from othertypes of metal cans. Limits of detection (3) for Pb in metal food can seamswere 0.1 and 0.3 mg Pb/cm 2 for count times of 1 hour and 3 minutes, respectively.Pb/Sn ratios were determined for commercial solders containing 0.6% to 84%Pb. Pb content was quantified as low as 0.07%, and Bi and Sb content couldbe determined for some commercial solders.

Application of different techniques to assess sediment quality and point source pollution in low-level contaminated estuarine recent sediments (Lisboa coast, Portugal)

Several X-ray techniques have been used in order to consider the chemical and mineralogical characterisation of recent superficial clay—silty sediments collected from the coastal shelf of the Atlantic Ocean, near Lisboa. Multi-element analyses have been carried out by means of total reflection X-ray fluorescence (TXRF) and radioisotope induced X-ray fluorescence (RIXRF). Mineralogical composition was determined using X-ray diffraction (XRD) methods. Particle size distribution was determined by means of a laser scattering technique. Statistical data treatment (correlation matrix, regression and factorial analysis) was used to identify elemental affinities and relationships among chemistry, mineralogy, texture and geographical distribution. The elements Ni, Cu, As and Pb show a marked relationship with clay minerals whose content is also correlated with the decreasing grain-size. Ti, Mn, Zr and V are grouped and may be related to the iron oxide content. Carbonates, Ca, Sr and quartz are correlated with the coarser grain-size fraction.

The optimization of the precision of the strontium/calcium ratio measurement in coral samples by radioisotope induced X-ray fluorescence

The estimation of sea surface water temperatures from the determination of the [Sr/Ca] atomic ratio in coral skeletons has been shown to be a promising method for investigating climate models. The determination of the Sr/Ca ratio by atomic absorption spectrometry was shown not to be acceptable because of the poor precision (around 3%), while more recently mass spectrometric methods were reported with less than 0.5% precision and accuracy. In this work, we have explored the optimization of the precision of the Sr/Ca ratio by radioisotope induced X-ray fluorescence, employing thin sample methods with 241 Am and 109Cd excitation sources. It was found that the precision for one determination could approach 0.5% and, for the determination of the Sr/Ca ratio for various aliquots, about 1.0% was found when the thin film (around 1 mg cm −2) method was employed with excitation by a 109Cd source. Finally, sea surface water temperatures were estimated using three recent Acropora coral specimens from the Los Roques archipelago; the results were similar to other values reported for tropical sea surface waters.

Noninvasive measurement of protein release from subcutaneous depo formulations in vivo using X-ray fluorescence

The feasibility of using radioisotope-induced X-ray fluorescence (XRF) as a noninvasive method to measure the release rate of peptides/proteins from hydrogels or other formulations in vivo following subcutaneous administration has been demonstrated. A sodium phosphate buffer solution (PBS) containing 52 mg/ml of iodinated bovine serum albumin (I-BSA) was administered subcutaneously in female Sprague-Dawley rats and the administration site was fluoresced at regular intervals over a 24–96 h period. The variation in the iodine X-ray yield with time indicated that the disappearance of I-BSA alone followed first order kinetics with a half-life of approximately 6.6 h. When the I-BSA was formulated into a polymeric hydrogel of poly(acrylic acid) (Carbopol-940), a significant increase in the half-life was observed. As the Carbopol concentration was increased from 5.61 to 18.75 mg/ml, the disappearance half-life increased from 6.3 to 14.0 h. Free iodide loaded into the Carbopol gel at equivalent concentrations had a disappearance half-life of 13.8 min.

Fluctuations in Fe, Cu, Zn, Br, As, Se, and Rb concentrations in C57L/J mice bearing BW7756 murine hepatoma using radioisotope-induced X-ray fluorescence

The effects of selenite or selenate supplementation on the concentration and distribution of Fe, Cu, Zn, As, Br, and Rb are investigated using the radioisotope-induced X-ray fluorescence, RIXRF. These effects are studied in the animals bearing BW7756 murine hepatoma and healthy animals for both of the oxidation states. Selenite and selenate induce different effects on the distribution of selenium, zinc, copper, bromine, and rubidium. The differences may be attributed to the differences in the inter element interaction after absorption into the bloodstream as well as to the mode of their intestinal absorption. Simultaneous supplementation of copper with selenite or selenate at the described levels has a profound influence on the concentration levels of other elements in the normal as well as in the diseased mice. The administration of selenium (0.67 micrograms/g body wt sodium selenite or sodium selenate, daily) and selenium and copper (0.67 and 1.35 micrograms/g body wt, respectively) has no effect on the incidence rate of hepatoma development.

Determination of selenium in animal tissue samples using radioisotope induced X-ray fluorescence

A simplified preconcentration procedure for the trace element profile studies of selenium using radioisotope induced X-ray fluorescence, RIXRF, is described. The method is based upon sample digestion followed by separation of selenium from the bulk by solvent extraction. The signal to noise ratios in the X-ray spectra are improved and interference from Br and As is significantly reduced. Levels of detection in the submicrogram range are achievable. Submicrogram quantities of selenium in animal tissues can be analyzed by the method.

Time-dependent distribution of selenate and selenite selenium in male C57L/J mice

The distribution and retention of selenate and selenite in C57L/J mice was investigated using 75Se radioisotope. The comparison is made with the normal distribution of the element determined by using radioisotope-induced x-ray fluorescence, RIXRF methods. The distribution of the two oxidation states measured as activity of 75Se was almost identical but differed from the normal trace elemental profile, TEP. The excretion rates of the two selenium species in the initial phase are different with more selenate being excreted than selenite in the first 2 days. It was found that the wholebody excretion rates followed a pure first-order pattern this was not true for the individual organs of the animals.

X-RAY FLUORESCENCE CHARACTERIZATION OF MING-DYNASTY PORCELAIN RESCUED FROM A SPANISH SHIPWRECK

A radioisotope induced X-ray fluorescence method was used to measure trace elements in Ming porcelain. Thirty pieces of blue-and-white Chinese porcelain, belonging to the Ch'eng Hua reign (AD 1465-87) and rescued from a shipwreck, were analysed along with two fake reproductions. The measurement system consisted of an Si(Li) detector, a 109Cd annular source and a personal computer with a non-linear fitting least-square program. The relative intensity ratios of manganese, cobalt, rubidium, strontium, zirconium, and niobium were determined. Rb/Sr and Mn/Co ratios between two to five and two to four respectively correspond to antique porcelain.

Level of some minor and trace elements in Bangladeshi meat products

An investigation on the level of some minor and trace elements in some varieties of meat (beef, mutton and chicken) consumed in Bangladesh is reported. In this study, protoninduced X-ray emission (PIXE) and radioisotope-induced X-ray fluorescence (XRF) techniques were used for analytical measurements. In PIXE measurements, the samples were exposed to the proton beam in air as 1 mm thick pellets and irradiated with 2.0 MeV protons having the beam intensity of 30 nA for characteristic X-ray excitation, whereas in XRF, the samples were excited for 5000 seconds with a 10 mCi109Cd annular X-ray source. The elemental concentrations of Ca, Mn, Fe, Ni, Cu, Zn, As, Se, Br, Rb and Sr were determined in the samples by comparison with X-ray yield curves constructed from IAEA and NBS standard reference materials. The significance of the results is dicussed in relation to human health and diseases.

The status of trace and minor elements in some Bangladeshi foodstuffs

An investigation is conducted on the status of trace and minor elements in some foodstuffs (cereals, vegetables, milk, egg and fish), commonly consumed in Bangladesh, using proton induced X-ray emission (PIXE) and radioisotope-induced X-ray fluorescence (XRF) techniques. In PIXE measurements, the samples were irradiated in air with 2.0 MeV (energy on the target) protons having the beam intensity of 30 nA for characteristic X-ray excitation, while in XRF analysis, the samples were excited for 5000 seconds with a 10 mCi Cd-109 annular X-ray source. The elemental concentration of K, Ca, Mn, Fe, Ni, Cu, Zn, Se, As, Br, Rb, Sr, Mo, and Pb were determined in the samples by comparison with X-ray yield curves constructed from IAEA and NBS standard reference materials. The validity of the analytical procedures (PIXE and XRF) followed in this study has been confirmed by comparative measurements of Cu, Zn and Mn in some varieties of rice with atomic absorption spectrophotometry. The results indicate that none of the food regimes investigated here is burdened with heavy metals beyond permissible limits except five species of vegetables with chromium having the range of 0.99–3.59 mg/kg compared to the literature value of 0.0–0.36 mg/kg (dry weight basis). An average value of 0.2 mg/kg of arsenic was observed both in IRRI (n=16) and local Aman (n=12) varieties of rice and only one hen egg contained 1.7 mg/kg of lead in yolk. The zinc content in some marine fish from Bay of Bengal was reported to be 5.4–19.5 mg/kg, whereas in the present study of sweet-water fish, the level is found to be 15.2–62.1 mg/kg (fresh weight basis) for five species. In human milk, both Cu (0.12–0.25 mg/l, n=8) and Zn (0.28–1.80 mg/l, n=8) levels appear to be almost half the literature values (n=25). On the other hand formula milk has higher values of Cu (0.32–1.63 mg/kg, n=16) and Zn (5.16–19.8 mg/kg, n=16).

Kβ/Kα intensity ratios for rare earth compounds using radioisotope induced X-ray fluorescence

Measurements of the Kβ to Kα intensity yield for the rare earth elements in various chemical compounds and as the pure elements have been made utilising radioisotope induced fluorescence and a hyperpure germanium (HpGe) detection system. Deviations from the ratios anticipated from theoretical considerations or from existing compilations have been found for LaB6, Ce(NH4)2(NO3)6, Pr6O11, Gd (citrate solution), Gd (EDTA solution), Tb4O7, Lu2O3, Lu (foil) and Eu in acid solution.

Dolomites formed under conditions of deep burial: Hunton Group carbonate rocks (Upper Ordovician to Lower Devonian) in the deep Anadarko Basin of Oklahoma and Texas

Progressive burial diagenesis of Hunton Group (Upper Ordovician to Lower Devonian) rocks of the deep Anadarko Basin of Oklahoma and the Texas Panhandle is evident from petrographic and geochemical study of cores and cuttings from more than 25 boreholes up to 30,000 ft deep. Limestone of the Hunton Group, which originated as shallow shelf carbonates, has been replaced, chiefly below present depths of about 10,000 ft, by dolomite that is commonly ferroan and is associated with shale. This diagenetic dolomite is inferred to have formed under deep-burial conditions. The dolomite occurs as finely disseminated, 10μm and larger rhombic crystals, and is most abundant near the base of the Hunton Group, particularly where an oolite unit (the Keel Formation) overlies the thick marine Sylvan Shale that is inferred to be the chief source of Fe2+ and Mg2+ ions. Ferroan dolomite also occurs where clay minerals are abundant in the Middle Hunton Group. In shallow wells, dolomite crystals are euhedral. Below 10,000 ft(3.0 km), where dolomitization of the oolite has been more complete, hypidiotopic and xenotopic textures result. Hydrocarbon-associated fluids are inferred to have dissolved the calcite that was not replaced, and to have created intercrystalline and moldic porosity. X-ray diffraction verifies a trend of higher dolomite concentrations with increasing depth in the same oolite horizon. For example, oolite samples from outcrop lack dolomite and are 100% CaCO3; cores from 9,200 ft (2.8 km) are about 25% dolomite; and cores from 15,000 ft (4.6 km) and below are more than 85% dolomite. Radioisotope-induced x-ray fluorescence shows that dolomites below 10,000 ft(3.0 km) are iron-enriched relative to both non-dolomitized oolite and dolomites of surface origin. Where the Hunton Group and the Sylvan Shale are buried below 10,000 ft(3.0 km), well logs show high densities in the lowermost Hunton (above the Sylvan Shale) which can be interpreted as the occurrence of Fe2+- rich dolomite. Stable isotope ratios suggest a higher temperature of origin for burial dolomites than for dolomites of surface origin. Formation waters recovered from within the shale and carbonate are greatly depleted in Mg2+ ions compared to normal marine waters. General restriction of this shale-associated ferroan dolomite to strate that are currently buried below 10,000 ft (3.0 km) in the Anadarko basin supports other lines of evidence for the belief that previously deeply buried strate can be recognized even if the strata have been subsequently uplifted. The transformation of smectite to illite in the Sylvan Shale (conformably underlying the oolite) is suggested as a possible source of Mg2+ and Fe2+. Smectite/illite ratio decreases with increasing depth in the Sylvan Shale. Furthermore, Sylvan Shale below 10,000 ft(3.0 km) is depleted in iron by 70% relative to Sylvan Shale less than 10,000 ft(3.0 km) deep, suggesting that under deep conditions shales have given up their iron (and magnesium), presumably to the overlying carbonates.

Trace element profiles of biological samples using radioisotope X-ray fluorescence

The trace element content determination of biological samples such as provided by biopsy or tissue section, require a unique approach. Radioisotope induced X-ray fluorescence (RIXRF) methods have been adopted to provide these criteria. Sensitivities of 10 15 atoms has been achieved in a nondestructive approach and utilized in tumor growth studies and studies involving atherosclerosis. Techniques for sample preparation and mounting and data reduction are presented.

Radioisotope induced x-ray emission — a complementary method to pixe analysis

It is shown that in some cases radioisotope induced X-ray fluorescence can be a useful complement to PIXE analysis. This is a consequence of the different dependence of the ionization cross sections on atomic number for each technique. The effects of X-ray absorption and particle range in matter are examined and illustrated by the analysis by both methods of clays and ceramics. The importance of a convenient choice of source-detector combination is emphasized.

Dolomites Formed Under Deep Burial Conditions: Hunton Group Carbonate Rocks (Upper Ordovician to Lower Devonian) in Deep Anadarko Basin of Oklahoma and Texas: ABSTRACT

Petrographic and geochemical study of cores and cuttings from 25 boreholes ranging in depth from near surface to 30,000 ft (9.1 km) of the Hunton Group (Upper Ordovician to Lower Devonian), in the deep Anadarko basin of Oklahoma and the Texas panhandle, shows progressive burial diagenesis with increased depth. Limestone conformably overlying shale has been diagenetically altered to dolomite, commonly ferroan, chiefly below current depths of 10,000 ft (3.0 km). The dolomite occurs as finely disseminated, 10 µm and larger rhombic crystals, and is most abundant near the base of the Hunton Group, particularly where an oolite unit overlies the thick marine Sylvan Shale inferred to be the chief source of Fe2+ and Mg2+ ions. Dolomite crystals are euhedral above about 10,000 ft (3 km). Below 10,000 ft, more complete dolomitization of the oolite produced hypidiotopic and xenotopic textures. Fluids associated with hydrocarbon migration (following dolomitization) dissolved the nonreplaced calcite, thereby creating intercrystalline and moldic porosity. X-ray diffraction verifies a trend of higher dolomite concentrations in the same oolite horizon with increasing depth. Oolite samples from outcrop lack dolomite (100% CaCO3); cores from 9,200 ft (2.8 km) are about 25% dolomite; and cores and cuttings from 15,000 ft (4.6 km) and below are +85% dolomite. Radioisotope-induced x-ray fluorescence shows that dolomites below 10,000 ft (3 km) are iron enriched relative to both nondolomitized oolite and dolomites of surface origin. We therefore conclude that dolomite has formed under deep burial conditions. End_of_Article - Last_Page 1317------------

Radioisotope-induced x-ray fluorescence termination of phenylmercury, methylmercury and inorganic mercury in water after preconcentration on diethylammonium diethyldithiocarbamate-loaded polyurethane foam discs

Polyurethane foam discs (7 mg cm −2 thick) loaded with diethylammonium diethyldithiocarbamate sob traces of mercury, methylmercury and phenylmercury ions quantitatively from aqueous solution. Matrix effects of the loaded polyurethane sorbent on the final measurement are low. Impurities in the foam do not interfere. The procedure is suitable for 0.3–2 μg cm 3 mercury with 25-cm 3 samples.

Radioisotope induced X-ray fluorescence analysis of cereal grains and flour

Radioisotope induced X-ray fluorescence analysis is a rather simple and convenient method for investigating ashed plant material. In order to reduce matrix effects, thin samples (2 mg/cm2) are analyzed to obtain a reasonable compromise between maximum sensitivity and the lowest possible absorption effects. Concentrations are determined by standard addition method. A precision of 6–8% can be achieved. As an application, analytical results are given for whole grains of several sorts of wheat.

Rapid determination of lead for industrial hygiene surveys

Emphasis on the continued reduction of personnel exposure to airborne lead has led to the development and evaluation of portable instrumentation for the rapid determination of microgram quantities of lead collected on air filter samples. The instrumentation is based on radioisotope-induced X-ray fluorescence; a cadmium-109 radioisotope source is used for sample excitation, and the characteristic lead X-rays emitted are measured by a proportional detector. The effects of excitation source geometry, particle size, and interferences from other elements were investigated. This type of portable instrumentation appears ideally suited for in-plant measurements intended to monitor lead and evaluate new control measures.