Determination of trace elements in Syrian medicinal plants and their infusions by energy dispersive X-ray fluorescence and total reflection X-ray fluorescence spectrometry

X-ray fluorescence (XRF) and total-reflection X-ray fluorescence (TXRF) techniques suited well for a multi-element determination of K, Ca, Mn, Fe, Cu, Zn, Rb, and Sr in some Syrian medicinal plant species. The accuracy and the precision of both techniques were verified by analyzing the Standard Reference Materials (SRM) peach-1547 and apple leaves-1515. A good agreement between the measured concentrations of the previously mentioned elements and the certified values were obtained with errors less than 10.7% for TXRF and 15.8% for XRF. The determination of Br was acceptable only by XRF with an error less than 24%. Furthermore, the XRF method showed a very good applicability for the determination of K, Ca, Mn, Fe, Cu, Zn, Rb, Sr, and Br in infusions of different Syrian medicinal plant species, namely anise (Anisum vulgare), licorice root (Glycyrrhiza glabra), and white wormwood (Artemisia herba-alba).     

偏振能量色散X射线荧光光谱法测定地质样品中18种元素

利用偏振能量色散X射线荧光光谱仪分析了硅酸盐基体样品. 选取岩石、土壤、水系沉积物等国家一级标准物质, 采用镶边粉末压片方法, 选择Al2O3偏振靶、 Mo、 Co二级靶, 在真空状态下对K、 Ca、 Ti、 Cr、 Mn、 Fe、 Ni、 Cu、 Zn、 Ga、 As、 Rb、 Sr、 Y、 Zr、 Nb、 Ba、 Pb等18种元素进行选择激发和探测, 所有元素的校正选用扩展的康普顿散射校正模型. 各元素的检出限为0.4～10.9 μg/g;除了As元素外, 均达到了1:25万多目标地球化学调查规范的要求. 根据60个地质调查多目标考核样品的分析结果, 采用Rousseau(2001)所提出的相对不确定度计算方法, 对所建立的方法进行了评估.     

Analysis of uranium ores by energy dispersive X-ray fluorescence

Summary The determination of uranium in ores by energy-dispersive X-ray fluorescence (XFA) is demonstrated for uranium ore samples of known content. For calibration silica gel standards are used. Matrix effects are corrected by measuring the Compton scattering peaks. The radionuclide ¹⁰⁹Cd as well as a X-ray tube in combination with Mo or Sn as secondary targets are suited as X-ray sources. The mean relative deviation of the values found from the given values is 5%

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Analyse von Uranerzen mit Hilfe der energiedispersiven Röntgenfluorescenz

Zusammenfassung Die Anwendbarkeit der energiedispersen Röntgenfluorescenzanalyse zur Bestimmung des Urangehaltes in Erzen wird am Beispiel von Uranerzproben bekannten Gehaltes demonstriert. Für die Eichung werden Kieselgel-Standards verwendet. Die Matrixeffekte werden mit Hilfe der ComptonStreupeaks korrigiert. Als Röntgenquellen eignen sich sowohl eine ¹⁰⁹Cd-Radionuklidquelle als auch eine Röntgenröhre mit Mo oder Sn als Sekundärtarget. Die mittlere relative Abweichung der Analysenwerte von den gegebenen Werten beträgt 5 %.

     

Chemometric methods in energy dispersive X-ray fluorescence

Chemometric methods like principal component regression (PCR) are an excellent tool for the determination of matrix parameters from scattered radiation. PCR is used for the determination of carbon, hydrogen and oxygen from water and oil-based samples. This information is used in combination with fundamental parameters to determine zink in liquid samples. The method allows an accurate prediction of element concentrations in strong varying matrices.     

Assessment of the Lake Gendabi salt for trace elements and toxic heavy metals by energy dispersive X-ray fluorescence spectrometry

This study has analyzed samples of salts from Lake Gendabi, located in the northern part of Tanzania for metal contamination using the EDXRF spectrometry. The aim of the study was to assess the suitability of the salt from Lake Gendabi for human consumption. Seventy-five samples of salt were collected from the Lake Gendabi floor and grouped into five grades (G1, G2, G3, G4 and G5) depending on the position of the salt from the lake shore. In addition to Na and Cl, concentrations of 17 more elements were determined in all five grades of salt. These included seven toxic metals which are Al, Ni, Cr, Cd, Pb as well as Th and U which are both toxic and radioactive. The concentrations of all toxic elements found in the samples were higher than their Maximum tolerable limits set by international organizations. As this salt is used in many parts of Tanzania, it is proposed that the salt should be thoroughly purified before entering the market. Further research to include salt samples from other salt production areas in Tanzania is recommended.     

Biomedical applications of energy dispersive X-ray fluorescence

An X-ray fluorescence method for in vitro analysis of trace elements in biological samples is presented. The method is characterised by the use of an X-ray tube with secondary targets as a monoenergetic radiation source, and by thin specimens. The method has been applied to the analysis of blood serum samples, gunshot residue and urinary calculi.     

X-ray fluorescence determinatin of trace elements in soil

Trace elements in soil are quantified by direct X-ray fluorescence method. Gallium is used an internal standard to compensate for variations in sample matrix, instrumental operating characteristics, and sample preparation. At the 50-mg kg^?1 level, V, Cr, Ni, Cu, Zn and As can be determined within a precision and accuracy of ± 20% or less. Sample prepartion is less elaborate than for some other methods.     

Heavy metals and some other elements in medicinal plants. Determined by X-ray fluorescence analysis

Determination of Mn, Fe, Cu, Zn, Hg, Pb, Br, Se, Rb, Sr and Cd in the medicinal plants by radionuclide X-ray fluorescence analysis (using²³⁸Pu,²⁴¹Am/Ag and¹²⁵I) is described.     

Determination of rare earth elements and thorium in britholite ore by energy dispersive X-ray fluorescence spectrometry

A radioisotope-excited X-ray fluorescence technique is applied for the determination of thorium and rare earth elements in britholite ore from Canada. An annular source of⁵⁷Co is employed for excitation of characteristic K X-rays of thorium and rare earth elements. The peak ratios of lanthanides were used to remove the difficulties because of overlapping lines at the 33–50 keV energy region. Matrix effects are examined also in detail and compensated for infinitely thick powdered ore sample. Results obtained in the analysis agree well with recommended values of Canada.     

Estimation of trace elements in some anti-epileptic medicinal plants by PIXE

Trace elemental analysis was carried out in various parts of 10 anti-epileptic medicinal plants using PIXE technique. A 3?MeV proton beam was used to excite the samples and spectra were recorded using a Si(Li) detector. Data analysis was done using Gupix Software. The elements Cl, K, Ca, Ti, Mn, Fe, Ni, Cu, Zn, Br and Sr were identified and their concentrations estimated. The presence of some of these trace elements is correlated with the anti-epileptic curative property of these plants.     

Investigation on major,minor and trace elements in some medicinal plants using Particle Induced X-ray Emission

Journal of Radioanalytical and Nuclear Chemistry - Elemental concentrations namely P, S, Cl, K, Ca, Sc, Ti, Mn, Fe, Cu, Zn, Rb, Br and Sr were determined using Particle Induced X-ray Emission...     

Direct rapid analysis of trace bioavailable soil macronutrients by chemometrics-assisted energy dispersive X-ray fluorescence and scattering spectrometry

Precision agriculture depends on the knowledge and management of soil quality (SQ), which calls for affordable, simple and rapid but accurate analysis of bioavailable soil nutrients. Conventional SQ analysis methods are tedious and expensive. We demonstrate the utility of a new chemometrics-assisted energy dispersive X-ray fluorescence and scattering (EDXRFS) spectroscopy method we have developed for direct rapid analysis of trace ‘bioavailable’ macronutrients (i.e. C, N, Na, Mg, P) in soils. The method exploits, in addition to X-ray fluorescence, the scatter peaks detected from soil pellets to develop a model for SQ analysis. Spectra were acquired from soil samples held in a Teflon holder analyzed using ¹⁰⁹Cd isotope source EDXRF spectrometer for 200 s. Chemometric techniques namely principal component analysis (PCA), partial least squares (PLS) and artificial neural networks (ANNs) were utilized for pattern recognition based on fluorescence and Compton scatter peaks regions, and to develop multivariate quantitative calibration models based on Compton scatter peak respectively. SQ analyses were realized with high CMD (R² > 0.9) and low SEP (0.01% for N and Na, 0.05% for C, 0.08% for Mg and 1.98 μg g⁻¹ for P). Comparison of predicted macronutrients with reference standards using a one-way ANOVA test showed no statistical difference at 95% confidence level. To the best of the authors’ knowledge, this is the first time that an XRF method has demonstrated utility in trace analysis of macronutrients in soil or related matrices.     

Determination of tungsten in ores by energy dispersive X-ray fluorescence analysis

The possible determination of tungsten in low grade ores from Northern India, Rajasthan State has been explored by energy dispersive X-ray fluorescence analysis /EDXRF/ technique using radioisotope based excitation of W L X-rays and high resolution Si/Li/ detector system. Finely powdered ore has been diluted with optimal quantity of cellulose and converted into pellets to make it suitable for X-ray analysis after homogenization. The experiments have shown the minimum detectable limit of 33 ppm in diluted matrix. The results are compared with the spectrophotometric stannous chloride-thiocyanate method. EDXRF appears to be encouraging for routine and precise analysis of tungsten in low grade ores.     

Titanium dioxide determination in sunscreen by energy dispersive X-ray fluorescence methodology

Nowadays there are many sun-protection cosmetics incorporating chemical and/or physical UV filters as active ingredients and there are no official methods to determine these kinds of compounds in sunscreen cosmetics. The objective of this work is to estimate TiO₂ concentration, without sample preparation, employing a portable energy dispersive X-ray fluorescence (EDXRF), aiming to estimate the sun protection factor (SPF) due to the physical barrier in sunscreen composition, and also identify the metals present in the samples. A portable EDXRF system was used for the analysis of fifteen commercial samples. It was also prepared three formulations estimated in FPS-30 using TiO₂ at 5%. Quantification was performed using calibration curves with standards from 1 to 30%. The physical barrier contribution in the SPF, associated to Ti concentration, was determined for all samples. The presence of some elements, like K, Zn, Br and Sr was detected in the sunscreen, identifying chemical elements that were not cited in the formulations. Three commercial samples were analyzed for total SPF determination and the result shows that the measured value is 10% lower than the nominal one.     

Rapid identification of inorganic salts using energy dispersive X-ray fluorescence.

A simple method for the rapid identification of inorganic salts used as raw materials during food production has been established using energy dispersive X-ray fluorescence (EDXRF). Intensities of Na, Mg, P, S, Cl, K, Ca, Mn, Fe, Cu, Zn Kalpha peaks have been measured. The treatment and comparison of the respective intensities allowed a rapid identification of inorganic salts. Two different methods of data treatment have been tested: K nearest neighbours (KNN) and centroids. Using cross validation on a database containing 140 samples representing 31 classes, a total of 98% of samples were well identified.     

Determination of yttrium in xenotime ore by energy dispersive X-ray fluorescence spectrometry

A radioisotope-excited X-ray fluorescence analysis is applied for the determination of yttrium in xenotime ore. An annular¹⁰⁹Cd source is employed for excitation of characteristic K X-rays of yttrium. The dilution method using pure starch as a diluent has been examined. Critical thickness of diluted ore sample has been determined. For the estimation of yttrium concentration in xenotime ore, the scattered radiation technique has been utilized. The validity and precision of the method have also been investigated.     

Micro energy dispersive X-ray fluorescence analysis of polychrome lead-glazed Portuguese faiences

Several glazed ceramic pieces, originally produced in Coimbra (Portugal), were submitted to elemental analysis, having as premise the pigment manufacture production recognition. Although having been produced in Coimbra, their location changed as time passed due to historical reasons. A recent exhibition in Coimbra brought together a great number of these pieces and in situ micro Energy Dispersive X-ray Fluorescence (µ-EDXRF) analyses were performed in order to achieve some chemical and physical data on the manufacture of faiences in Coimbra.     

Effect of helium environment and mylar foil on the sensitivity of different elements in energy dispersive X-ray fluorescence spectroscopy

Analysis by Energy Dispersive X-Ray Fluorescence (ED-XRF) technique of liquid samples and specimens in aqueous media requires that the sample chamber be flushed with helium gas. Moreover the sample should also be covered with mylar foil to hold the sample. The helium environment and the X-ray beam but also affect the sensitivity of different elements. An investigation was carried out with six multielement NBS standards to evaluate the effect of helium environment and mylar foil on the sensitivity of various elements. The effect of both the factors can be employed to improve the results of liquid samples with ED-XRF technique.     

Zirconium and hafnium determination by energy dispersive X-ray fluorescence with solid phase preconcentration

Two preconcentration methods has been developed for simultaneous determination of zirconium and hafnium by energy dispersive X-ray fluorescence (EDXRF). The first method is a liquid-solid extraction procedure with the use of an anionic exchange resin modified with xylenol orange. The second is a precipitation procedure carried out in the presence of lanthanum. Both methods permit significant enhancement of sensitivity in comparison with direct measurement in the aqueous phase. The applicability of both procedures for the preconcentration of Zr and Hf prior to their determination by EDXRF was demonstrated by analyzing synthetic mixtures and a sample of zirconium ore. The results obtained with the use of the modified resin show relative standard deviation of about 4% and good agreement with those obtained by spectrographic analysis.     

A new X-ray pinhole camera for energy dispersive X-ray fluorescence imaging with high-energy and high-spatial resolution

A new X-ray pinhole camera for the Energy Dispersive X-ray Fluorescence (ED-XRF) imaging of materials with high-energy and high-spatial resolution, was designed and developed. It consists of a back-illuminated and deep depleted CCD detector (composed of 1024 × 1024 pixels with a lateral size of 13 μm) coupled to a 70 μm laser-drilled pinhole-collimator, positioned between the sample under analysis and the CCD. The X-ray pinhole camera works in a coaxial geometry allowing a wide range of magnification values.The characteristic X-ray fluorescence is induced on the samples by irradiation with an external X-ray tube working at a maximum power of 100 W (50 kV and 2 mA operating conditions).The spectroscopic capabilities of the X-ray pinhole camera were accurately investigated. Energy response and energy calibration of the CCD detector were determined by irradiating pure target-materials emitting characteristic X-rays in the energy working-domain of the system (between 3 keV and 30 keV).Measurements were performed by using a multi-frame acquisition in single-photon counting. The characteristic X-ray spectra were obtained by an automated processing of the acquired images. The energy resolution measured at the Fe–Kα line is 157 eV.The use of the X-ray pinhole camera for the 2D resolved elemental analysis was investigated by using reference-patterns of different materials and geometries. The possibility of the elemental mapping of samples up to an area of 3 × 3 cm² was demonstrated.Finally, the spatial resolution of the pinhole camera was measured by analyzing the profile function of a sharp-edge. The spatial resolution determined at the magnification values of 3.2 × and 0.8 × (used as testing values) is about 90 μm and 190 μm respectively.