Total Reflection X-ray Fluorescence Technique Research Articles

Trace element concentration in São Francisco River water using STXRF and PIXE techniques

Trace element concentrations in water from Sao Francisco River using Particle Induced X-ray Emission (PIXE) and Synchroton Total Reflection X-ray Fluorescence (STXRF) techniques are measured. The main objective of this work was to characterize and to monitor the trace elements in the water of Sao Francisco River, as well as to provide valuable information about the levels of metallic ions pollutants. Water samples were collected monthly at five locations along the course of the river from July 2003 to April 2004. As an internal standard, 11.6 ppm of Yttrium was added to 10 ml of the water sample. The PIXE and TXRF measurements were performed at the Ion Beams and Materials Laboratory (LAMFI) and the Brazilian National Synchrotron Light Laboratory (LNLS), using a proton beam and a polychromatic X-ray beam, respectively. Si(Li) detectors were used to collect the X-ray spectra. Due to the excellent detection limits of the PIXE and STXRF analysis, up to 15 elements were quantified. The highest total content of Cr, As, Cu and Zn detected in river water are above the limits recommended by the environmental legislation.

Ion irradiation damage on tin side surface of float glass

Changes in the surface morphology and in-depth density variation in two surfaces of a float glass viz. the tin side and non-tin side surface, are investigated after 100keV Ar ion irradiation. In the tin side surface, the irradiation caused a drastic change in density and surface roughness, whereas the other side (non-tin side surface) remained almost unaffected. Roughness of the tin side increases from 8Å to 41Å. Surface density also modified significantly with a redistribution of surface impurities. Monte Carlo simulations suggest that the displacement of tin and Fe impurities are responsible for the surface damage, which are experimentally examined by employing the total reflection X-ray fluorescence technique. Morphological and density changes are analyzed by grazing incidence X-ray reflectivity and atomic force microscopy techniques. Subsequent changes in surface morphology of float glass by ion irradiation are explained.

Non-destructive surface characterization of float glass: X-ray reflectivity and grazing incidence X-ray fluorescence analysis

In the present study we have carried out non-destructive surface characterization of a float glass using total reflection X-ray fluorescence (TXRF) technique and X-ray reflectivity (XRR). The in-depth distribution of Sn and Fe impurities has been determined by TXRF where as X-ray optical properties such as r.m.s surface roughness, refractive index, etc., have been derived by XRR. The results obtained so are used in analyzing the soft X-ray optical constants in the wavelength region of 80–200 Å. The results obtained indicate that two surfaces of float glass differ significantly.

Assessment of trace metals composition of vegetable <i>Amaranthus spinosus</i> (Linn species) grown along urban motorways using TXRF technique

Vegetables of Amaranthus Spinosus Linn species, commonly grown along urban motorways, were sampled in three different locations along motorways in Ile Ife, Nigeria. The washed and unwashed leaves, stems and roots portions of the vegetable samples as well as the soil samples from each site were separated for independent analysis. All samples were digested using analytical grade acids and subsequently analysed using Total Reflection X-ray Fluorescence (TXRF) technique. Elements identified mainly in the samples are K, Ca, Ti, Mn, Fe, Cu, Zn, Br, Rb, Sr and Pb. Enrichment factors and soil-to-plant transfer ratios (TRs-p) of the metals for each vegetable sample were determined. The enrichment factors reveal that anthropogenic contributions increased the levels of some elements: Cr, Mn, Br, Sr and Pb, in the vegetable samples. Key Words: TXRF, Amaranthus Spinosus Linn, soil-to-plant transfer ratio, toxicity, enrichment factor Ife Journal of Science Vol.6(1) 2004: 45-49

Near-edge absorption spectroscopy of interplanetary dust particles

Interplanetary Dust Particles (IDPs) are derived from primitive Solar System bodies like asteroids and comets. Studies of IDPs provide a window onto the origins of the solar system and presolar interstellar environments. We are using Total Reflection X-ray Fluorescence (TXRF) techniques developed for the measurement of the cleanliness of silicon wafer surfaces to analyze these particles with high detection sensitivity. In addition to elemental analysis of the particles, we have collected X-ray Absorption Near-Edge spectra in a grazing incidence geometry at the Fe and Ni absorption edges for particles placed on a silicon wafer substrate. We find that the iron is dominated by Fe2O3.

Study of a novel labelled scleroglucan macromolecule

A fast and rapid chemical reaction is presented here for labelling the polysaccharide scleroglucan with iodine to simplify its detection. The conditions proposed for the chemical reaction (temperature, concentrations of reactants and pH) were selected so as to substitute only a few of the OH groups in the polymer. The quantification of the labelled macromolecule is possible by radioactivity or Total Reflection X-ray Fluorescence techniques, depending on the iodine isotope used. Both techniques were adjusted for their use in labelled (with 127I or 131I) scleroglucan solutions. A comparison of the molecular weight distribution and the viscosity between solutions of the labelled product and the original one is performed and no major differences were found.

Determination of some heavy metals (Fe, Cu, Zn and Pb) in blood by total reflection X-ray fluorescence

The main purpose of this study is the interaction between nutrition (micronutrients heavy metals: Fe, Zn, Cu) and toxic heavy metals such as Pb in blood of children living in Gharb region of Morocco. This region receives all pollution carried by the Sebou river coming mainly from industrial activities. A rapid and simple analytical procedure was used for the determination of Fe, Cu and Zn trace amounts in blood by total-reflection X-ray fluorescence technique. This method is an energy dispersive XRF technique in a special geometry of primary beam, sample and detector. The sample is deposited on a plane polished surface of a suitable reflector material. It is presented as a few drops (25 μl) from a solution of blood digested in a mixture of HNO 3 and H 2 O 2 using a microwaves accelerated reaction system. The accuracy of measurements has been investigated by using certified materials. The concentration of Cu was found to be normal in all samples (≅ 1 ppm) which ruled out any interaction between this element and the others. On the other hand, amounts of Fe and Zn are very variables, suggesting an interaction between Fe and Zn. However, amounts of Pb in blood are inferior to 50 ppb, suggesting that no interaction exist with this metal and micronutrients.

Characterization of iron, copper and zinc levels in the colostrum of mothers of term and pre-term infants before and after pasteurization

Pasteurization is a thermal treatment applied to the milk used in human milk banks so as to provoke the thermic inactivation of pathogenic micro-organisms, with the aim of avoiding contamination of milk that will be offered to new-born infants in clinical conditions very often demanding special care. The literature has very little data available relating to the effect of pasteurization on the concentration of oligo-elements in human milk. The objective of this study was to evaluate the effect of pasteurization on the concentrations of iron (Fe), copper (Cu) and zinc (Zn) in the colostrum of mothers of pre-term (PT) and term (T) infants. Samples were collected from the day of birth to the seventh day after birth. The oligo-elements were analyzed using the total reflection X-ray fluorescence technique with synchrotron radiation. The following results of Fe, Cu and Zn (means±SD) were obtained for the PT and T colostrum samples, non-pasteurized and pasteurized, respectively: PT: 1.96±0.73 mg/l Fe/1.71±0.70 mg/l Fe, 0.67±0.28 mg/l Cu/0.64±0.28 mg/l Cu, 5.55±2.71 mg/l Zn/5.39±2.73 mg/l Zn; T: 1.71±1.01 mg/l Fe/1.46±0.99 mg/l Fe, 0.54±0.29 mg/l Cu/0.49±0.19 mg/l Cu, 6.97±2.82 mg/l Zn/6.75±2.62 mg/l Zn. There was a significant reduction in the levels of Fe, Cu and Zn in the samples of pasteurized colostrum. These results suggest that, despite the observance of a diminution in the levels of Fe, Cu and Zn in the samples of pasteurized colostrum, the values fell within the acceptable range for the specific nutritional needs of new-born infants during this period of lactation.

Assessment of serum selenium levels in 2-month-old sucking calves using total reflection X-ray fluorescence technique

The assessment of selenium status of livestock plays an important role in the production of medicine since low serum Se levels influence disease resistance in ruminants. It has been proved that Se deficiency may cause muscular dystrophy, cardiomyopathy and even death. Serum level has been widely used to evaluate the Se short-term status in animals since there is a good association between serum Se level and the dietary intake of the element over a wide range. The purpose of this work was to determine the Se serum concentration in a population of 78 sucking 2-month-old calves, in order to corroborate a clinical diagnosis of severe deficiency status. The samples were analyzed by total reflection X-ray fluorescence (TXRF) at the ITAL STRUCTURES Research Laboratory. The results obtained from the serum samples presented Se concentrations varying from 10 to 66 ng/ml. The comparison between the obtained values and the expected serum selenium values (60–80 ng/ml), confirmed a mild to severe deficiency status in the investigated population.

Determination of the rare-earth∶Nb mass ratio in doped LiNbO3 by the TXRF technique

This paper describes a new method for evaluating the mass contents of rare-earth elements used as dopants in LiNbO3 single crystals with respect to Nb. The method is based on the technique of total-reflection X-ray fluorescence (TXRF). The method presented does not require chemical manipulation of the samples and is rapid (30 min sample preparation and 10 min analysis), precise (between 2 and 8% of variation coefficient) and simple.

Determination of metal-ligand stoichiometries for inorganic complexes using total reflection X-ray fluorescence.

The methods usually used to determine the ratio metal-ligand in inorganic complexes require a set of solutions with different concentrations for both the ligand and metal. We propose a new method using the total reflection X-ray fluorescence technique, in which the ratio between metal and ligand is determined precisely, easily, and quickly. Experimental results provide evidence that for different chemical complexes, the ligand-metal ratio determined by this technique deviates at most from stoichiometric values by 6%. The technique is restricted usually to elements with Z above 14, and its detection limit is on the order of 10(-8) g/g.

Determination of trace elements in pharmaceutical substances by graphite furnace atomic absorption spectrometry and total reflection X-ray fluorescence after flow injection ion-exchange preconcentration

Flow injection iminodiacetic acid ethyl cellulose (IDAEC) microcolumn preconcentration and graphite furnace atomic absorption spectrometry determination of trace metals (Cd, Co, Ni, Pb) were carried out without decomposition of the drug matrix. The two forms of chromium Cr(III) and Cr(VI) were separated using IDAEC and anion exchanger diethylaminoethyl (DE)-cellulose, respectively. The detection limits of trace elements in pharmaceutical substances (sugars, sorbitol, mannitol, paracetamol, amidopyrine, chloral hydrate) after a 10-fold preconcentration in 1–5% m/v solution of pharmaceuticals were in the 0.3–29 ng g −1 range. The measured concentration of trace elements in substances investigated was below 100 ng g −1. The spike recovery was close to 100%. The capability of total reflection X-ray fluorescence technique for the determination of trace elements in pharmaceuticals with and without preconcentation was explored.

Comparison between proton-induced x-ray emission (PIXE) and total reflection x-ray fluorescence (TXRF) spectrometry for the elemental analysis of human amniotic fluid

A comparison between use of proton-induced x-ray emission (PIXE) and total reflection x-ray fluorescence (TXRF) techniques in relation to the elemental analysis of amniotic fluid (AF) was carried out by measuring the concentrations of Cl, K, Ca, Fe, Cu, Zn and Br. For 10 AF samples analyzed, the agreement between PIXE and a TXRF measurements was 100% for K, 60% for Cl and Ca, 80% for Fe and 50% for Cu. For Zn, although there was only a 20% agreement, the measured concentrations ranged between 0.1 and 1 μg/ml with a TXRF standard deviation as high as 0.070 μg/ml. For Br, a factor of 1.8±0.2 was obtained between TXRF and PIXE measurements, suggesting a systematic error between experiments. This work indicates that further investigation is required to determine the experimental conditions, e.g. sample preparation and irradiation, which lead to complete agreement between TXRF and PIXE when a complicated organic sample such as amniotic fluid is analyzed. Copyright © 1999 John Wiley & Sons, Ltd.

Performance of total reflection and grazing emission X-ray fluorescence spectrometry for the determination of trace metals in drinking water in relation to other analytical techniques

An intercomparison survey has been carried out in order to evaluate the performance of two related X-ray fluorescence techniques as compared to the achievements of several other analytical techniques applied for trace elements determination in drinking water. A relatively new technique, total reflection X-ray fluorescence (TXRF) and a novel related technique, grazing emission X-ray fluorescence (GEXRF) have been used for the analysis of a mineral water sample. The concentrations of the following elements have been determined: Na, Mg, K, Ca, Ni, Cu, Zn and Sr. The mineral water sample has also been analyzed by a number of other analytical techniques, routinely utilized in drinking water quality control. The analyses were performed in eleven laboratories which reported 286 individual determinations producing 75 laboratory means. From the obtained results, it can be concluded that the TXRF technique is suitable for a direct determination of heavy elements in drinking water (above potassium, Z = 19). This technique can compete with other analytical techniques routinely used in water quality monitoring. First results obtained with GEXRF spectrometry show that this technique can be successfully applied for the determination of low-Z elements in drinking water. However, results for sodium and magnesium were systematically too low, indicating that modifications of the quantification procedure may be required to improve the accuracy of determination for these light elements.

Determination of mercury by total-reflection X-ray fluorescence using amalgamation with gold

Analysis by total-reflection X-ray fluorescence (TXRF) is unsuitable for determining mercury concentrations because the usual sample preparation produces evaporation and loss of this element as a consequence of its high vapour pressure and low boiling point. A method that has been developed to achieve this determination involves forming an amalgam while a thin layer of silver (obtained by sputtering or evaporation) is in contact with an ionic solution of Hg; subsequently, a traditional TXRF analysis is performed. This was the first method reported in the literature to apply the TXRF technique for reliably determining mercury concentrations with high sensitivity. This work shows how a similar procedure may be employed to measure mercury concentrations. This second method involves forming an amalgam of gold using microlitre quantities of the solution to be analysed. As gold is a highly malleable material, it allows the production of very thin films, the weight of which is a few orders of magnitude higher than the mass of mercury present in the amalgam. The determination is performed in the usual way using the TXRF technique. The sensitivity of this method (≈ 5 ppm) is inferior to that of the former method, and data processing is quite difficult because the peaks for mercury and gold overlap, but the experiment is simple to execute and improved sensitivity is expected to be attained by forming the amalgam with larger volumes of sample and with a more responsive data processing scheme.

A New Method for the Determination of S, V, Fe, Ni, Pb and Other Elements in Some Distilled Fractions of Crude Petroleum by TXRF

The possibility of employing the Total Reflection X-ray fluorescence (TXRF) technique for the analysis of some derivatives of petroleum crude oil (Petrol, Diesel oil, Fuel oil), is demonstrated with the help of certified standards (NIST, ENEL, ICIP). The quantitative analysis is conducted via an internal standard method. Some problems about elements volatility (S in Diesel oil and Pb in Petrol) are solved to permit an accurate quantitative simultaneous determination of the elements (from Z = 13 to Z = 90 with a detection limit in the range from ppb to ppm) present in the samples of petroleum derivatives. The analyses are conducted with a new Total - Reflection X-ray spectrometer (TX 2000 supplied by Ital Structures)

Total reflection x-ray fluorescence analysis of planarized semiconductor product wafers

The use and effectiveness of total reflection x-ray fluorescence (TXRF) have been widely reported. The application of this technique in semiconductor fabrication has become popular and several instrument vendors now make equipment optimized for this particular purpose. Because sample surfaces must be optically flat in order to achieve the total reflectance condition, the majority of the work in investigating semiconductor processing is performed on monitor wafers. The use of TXRF for in-line process control, therefore, has been limited to silicon or dielectric film substrates, either on the surface or the backside of the wafer. This article details the use of TXRF analysis for monitoring the contamination present on production-wafer surfaces, after planarization techniques have been used. The wafer surfaces at several of these planarization steps meet the criteria for the application of the TXRF technique using the normal operating conditions of the TXRF instrument. This technique can be used as process-monitoring tool to study wafer surfaces for particular contaminants that affect wafer yield. TXRF is being used on IBM’s state-of-the-art DRAM and logic circuits.

Heavy metal speciation in coastal sediments using total-reflection X-ray fluorescence spectrometry

The chemical forms of K, Ca, Ti, Mn, Fe, Ba, Rb, Cr, Cu, Sr, Zn and Pb in the sediments of St. Gilla Lagoon (Sardinia, Italy) are evaluated. Five fractions, consisting of an exchangeable metal fraction, metals bound to carbonates, metals bound to iron and manganese (hydr)oxides, metals bound to organic matter and a fraction of residual metals were separated from sediments by sequential chemical extraction. The metals in each fraction were determined by the total-reflection X-ray fluorescence (TXRF) technique. Both principal and trace element distributions in the sequential phases are discussed in terms of pollution sources, metal transport and deposition/redeposition in air dried sediments.

TXRF High Sensitivity X-Ray Analyzer With Multi-Layer Monochromator

Total reflection X-ray Fluorescence (TXRF) has been applied to the detection and quantification of metal contamination on the surface and near-surface regions of silicon wafers in the semiconductor industry The need for improving the sensitivity and detection limit of the TXRF technique is driven by the progress in producing thinner films and finer features in the development of larger Mbit DRAMS.

TXRF Spectrometric Analysis of Major Elements in Mineral Sands

The major elements of mineral sands such as rutile and ilmenite vary widely in their concentrations. A method is developed with the use of thin-film samples and the total reflection x-ray fluorescence technique to obtain quantitative concentrations of such samples. The method was tested with the use of the GSJ (Geological Survey of Japan) rock reference JB-3, and agreement with quoted values was good. The advantages of the method are the simplicity of sample preparation, including easy removal of samples from the reflector; the low background contribution from the substrate; and the small quantity of the sample that is required.