Direct analysis of essential oils by means of TXRF spectrometry

Direct analysis of essential oil has been performed for estimation of the elemental content in five different extracted essential oils from the leaves of different plants, namely, Mentha longifolia, Rosmarinus officinalis, Ocimum basilicum, Elletaria cardamomum, and Lavandula hybrida. A benchtop total reflection X-ray fluorescence spectrometer with a maximum power of 40 W was used for this purpose. Fourteen elements have been quantified in most of the extracted essential oil samples, and their limits of detection were determined. The detected elements are P, S, Cl, K, Ca, Cr, Mn, Fe, Ni, Cu, Zn, As, Br, Ni, and Hf. The validity of the present method was demonstrated using a standard reference material of organometallic oil sample. Two extraction methods of essential oils from leaves of the mentioned plants are evaluated, namely, classical hydro-distillation and microwave-assisted hydro-distillation. The quantitative elemental analysis of the extracted essential oils using the two extracted methods was studied and compared.     

In-Situ Monitoring of Chromium Uptake in Different Parts of the Wheat Seedling (Triticum aestivum) using Laser-Induced Breakdown Spectroscopy

The present work is a methodological study to investigate the effect of chromium (VI) stress on wheat seedlings. Point detection capability of laser-induced breakdown spectroscopy (LIBS) was utilized for the monitoring of in-situ chromium uptake in wheat (Triticum aestivum) seedlings. Chromium accumulation and its effects on other elements in wheat seedling were investigated by comparing the intensities of spectral lines of chromium and other minerals present in the LIBS spectra. In-situ LIBS spectra of the different parts of the wheat seedlings were recorded by directly focusing the laser beam on the surface of root, stem, and leaf of the seedlings grown with and without chromium-containing solutions. The spectra obtained from the different parts (root, stem, and leaf) of the wheat plant were analyzed to determine the distribution pattern/accumulation of chromium. Effect of the chromium uptake on the distribution pattern of other elements like calcium (Ca), magnesium (Mg), sodium (Na), and potassium (K) was also investigated. It was observed that chromium concentrations in plant organs decreased in the following order: roots > leaves > stems.     

SR-XRF analysis and assessment in urban ecology studies: The case of Novosibirsk

This paper considers the elemental composition of aerosols which have accumulated in the snow in winter and that of the top soil layer (0–5 cm), birch (Betula pendula Roth.) leaves collected at the end of the vegetative season, and soils in the vicinity of Novosibirsk. The analysis is carried out using the X-ray fluorescence elemental analysis with synchrotron radiation (SR-XRF) method, which helps reveal the existing local aerosol pollution from industrial sources. The main geochemical indicators of aerosol pollution of the Novosibirsk tin smelter (Novosibirskii Olovokombinat) are As, Sn, Tl, Cd, and Pb; those of three Novosibirsk heat power stations TETs-2, -3, and -5 are V, Mn, I, and Ga. It is found that the accumulation of the majority of technogenic elements in the tissues of higher plants depends on the intensity of the pollution, except for the biophilic Cu, Zn, and Mn, the content of which is more regulated by the physiobiological mechanisms of plants. For example, birch leaves are found to have a lower Mn content in the areas of high technogenic pollution, whereas, in ecologically clean areas, the Mn content in plant tissues is observed to increase. Thus, in Siberia, the snow cover and vegetation are the seasonal depositing components of the urban environment that adequately reflect the existing technogenic aerosol pollution. The elemental SR-XRF analysis of snow and plant tissues can be used to carry out a timely and reliable environmental assessment of an urban territory.     

Radioisotope‐induced EDXRF investigation of elemental uptake in cauliflower grown at MSW‐contaminated site

A ¹⁰⁹Cd radioisotope‐induced energy dispersive X‐ray fluorescence (EDXRF) study has been performed on samples of cauliflower consisting of the flower, the leaves and the associated root soil. The cauliflowers are collected from farms near the main dumping site of municipal solid waste (MSW) in the city of Kolkata, India, and also from uncontaminated farms about 50 km away from the city. The systematic investigation is primarily aimed at achieving two correlated objectives. Firstly, a unified calibration approach is undertaken for the study tool viz., EDXRF spectrometer, through the use of same instrumental scattering constants for quantification in widely differing matrices like soil and plant. Quality control was done by quantitative reproduction of National Institute of Standards and Technology–Standard Reference Materials (NIST–SRMs). Subsequently, the second objective is to comparatively study elemental uptake in the cauliflower samples from contaminated and uncontaminated farms using the same calibration. This study suggests that the elemental concentrations in the root soils and leaves of the samples vary from farm to farm, whereby the concentrations of Cu, Zn and Pb in root soils of MSW‐contaminated farms are higher by almost an order of magnitude compared to uncontaminated farms. But the most notable feature of this study is the strikingly similar elemental concentrations in the edible flower part of all samples irrespective of the soil type. Plots of the ratio of concentrations of elements in leaf to soil and in flower to leaf, observed from the present EDXRF study suggests that a preferential uptake of elements takes place at different stages. Copyright © 2010 John Wiley & Sons, Ltd.     

Estimation of trace elements in some medicinal plants used in anti‐cancer drugs by PIXE

A trace elemental analysis was carried out in various parts of 12 anticancer medicinal plants, using the PIXE (particle‐induced X‐ray emission) 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 the GUPIX software. The elements Cl, K, Ca, Ti, V, Mn, Fe, Ni, Cu, Zn, Br and Sr were identified, and their concentrations estimated. The results of the present study provide justification for the usage of these medicinal plants in the development of anticancer drugs. Copyright © 2012 John Wiley & Sons, Ltd.     

The determination of the parameters of sub- and supercritical extraction of plant raw materials

The extraction of biologically active substances by carbon dioxide from various plant raw materials (amaranth seeds, Sophora japonica flower buds, Stephania rotunda stems, and Stevia rebaudiana leaves) was studied at sub- and supercritical parameters. A laboratory unit for the extraction of plant raw materials by liquefied gases and supercritical fluids at 5–35 MPa pressures and 285–350 K temperatures was developed. The maximum yield of the extracted substances from plants specified was obtained at temperature and pressure exceeding the critical parameters of CO₂ (320–330 K, 28–30 MPa).     

Extending the quantitative analytical capabilities of the EDXRF technique for plant‐based samples

The energy‐dispersive x‐ray fluorescence (EDXRF) technique has limitations in the quantitative analysis of light elements (low‐Z analytes with Z < 10), for many reasons. This work, however, circumvents the problem through an a priori determination of low‐Z analytes, representative of plant‐based samples. The main purpose of this work was to characterize the major elements in the dark matrix of some plant‐based samples (including biomonitors) using Rutherford backscattering spectrometry (RBS), and the results provided as a generalized input for EDXRF analysis. The derived stoichiometry and mass ratio for the moss, lichen, and cotton cellulose samples analyzed were found to be similar and close to C₇H₁₀O₅, with an average matrix of C = 49.8%, H = 4.0% and O = 45.8%. Quantitative analysis of plant‐based reference material IAEA‐336 (lichen) was subsequently carried out. Use of the a priori determined dark matrix elements (from one‐time RBS spectrometry) extended the scope of applicability of the EDXRF quantitative methods used, and improved accuracy in the elemental analysis of plant‐based samples. The results obtained were in good agreement with the reference values. Copyright © 2004 John Wiley & Sons, Ltd.     

Elemental concentration analysis in some plant samples by EDXRF at Trabzon

The elemental analysis of some plant samples have been carried out in Trabzon region (Turkey) using energy-dispersive X-ray fluorescence (EDXRF) spectrometry. We have analyzed plant samples for nine stations using 1.85 GBq ⁵⁵Fe radioactive sources. We have found that potassium and calcium within 0.3-1.4% and 0.3-2.8% were present in concentration in plants for every station, respectively. The concentration of Cl and Ti generally changed according to the plant species and the sampling station.     

Energy-dispersive X-ray fluorescence study of elemental uptake in cauliflower

A ¹⁰⁹Cd radioisotope-induced energy-dispersive X-ray fluorescence (EDXRF) study has been performed on samples of cauliflower consisting of the flower, the leaves and the associated root soil. The cauliflowers were collected from farms near the main dumping site of municipal solid waste in the city of Kolkata, India and also from uncontaminated farms about 50 km away from the city. A unified calibration approach was undertaken for the elemental analysis of the samples of widely varying matrices. The present study suggests that the elemental concentrations in the root soils and leaves of the samples vary from farm to farm, whereby the concentrations of Cu, Zn and Pb in root soils of MSW-contaminated farms are higher by almost an order of magnitude compared to uncontaminated farms. But, the most notable feature of this study is the strikingly similar elemental concentrations in the edible flower part of all samples irrespective of the type of soil.     

Application of X-ray fluorescence spectrometry in plant science: Solutions,threats, and opportunities

X-ray fluorescence (XRF) spectrometry is a nondestructive, rapid, simultaneous multi-elemental imaging methodology for plant materials. Its applications are broad and cover most of the elements with varying concentration below the parts per million (ppm). XRF is a well-established atomic spectrometric technique that is also being used as a field portable instrumentation. In recent decades, XRF has been considered a very versatile tool for plant nutrition diagnosis due to its fast and multi-elemental analytical imaging response directly from a solid sample. In this review, we have mainly focused on the recent developments and advancements in XRF spectrometry to analyze plant materials. We have also included the fundamental aspects and instrumentation for XRF spectrometry for its use in plants imaging. We have also covered the use of XRF for vegetal tissues and plant leaves. Mainly, we have briefly focused on some features of sampling procedures and calibration strategies regarding the use of XRF for plant tissues. Microchemical imaging applications by XRF, μ-XRF, μ-SRXRF, and TXRF have been covered for a wide variety of plant tissues such as leaves, roots, stems, and seeds.     

Application of total reflection X-ray fluorescence spectrometry for trace elemental analysis of rainwater

Applicability of total reflection X-ray fluorescence (TXRF) spectrometry for trace elemental analysis of rainwater samples was studied. The study was used to develop these samples as rainwater standards by the National University of Singapore (NUS). Our laboratory was one of the participants to use TXRF for this study. The rainwater sample obtained from NUS was analysed by TXRF and the trace elements Mn, Fe, Ni, Cu, Zn, V and Pb were determined as required by the NUS. The average precision was found to be within 16% and the TXRF-determined elemental concentrations of these elements were below 20 μg/l. The average deviation of TXRF-determined values from the certified values were 20% (excluding the deviation for Fe and V which were comparatively high). Apart from the above elements, S, K, Ca, Rb, Sr, Ba and Br were also determined by TXRF and were found to be in the range of 0.2 to 191 μg/l. TXRF-determined values of our laboratory played an important role in the certification of concentration of seven elements in this rainwater sample which was later developed as a rainwater standard.     

Chromium localization in plant tissues of Lycopersicum esculentum Mill using ICP-MS and ion microscopy (SIMS)

High-resolution imaging secondary ion mass spectrometry (HRI-SIMS) in combination with inductively coupled plasma mass spectrometry (ICP-MS) were utilised to determine specific sites of chromium concentration in tomato plant tissues (roots, stems and leaves). The tissues were obtained from plants grown for 2 months in hydroponic conditions with Cr added in a form chromium salt (CrCl₃·6H₂O) to concentrations of 25 and 50 mg/L. The chemical fixation procedure used permit to localize only insoluble or strongly bound Cr components in tomato plant tissue. In this work no quantitative SIMS analysis was made. HRI-SIMS analysis revealed that the transport of chromium is restricted to the vascular system of roots, stems and leaves. No Cr was detected in epidermis, palisade parenchyma and spongy parenchyma cells of the leaves. The SIMS-300 spectra obtained from the tissues confirm the HRI-SIMS observations. The roots, and especially walls of xylem vessels, were determined as the principal site of chromium accumulation in tomato plants.     

EDXRF for elemental determination of nanoparticle-related agricultural samples

The number of studies dealing with nanoparticles (NPs) and plants has increased. They subsidize the advances of agriculture in the 21st century; however, so far, beneficial as well as detrimental results have been reported. In this context, analytical tools for monitoring macronutrients and micronutrients in plants exposed to NPs, with adequate performance and low cost, are required. This work assesses the use of energy-dispersive X-ray fluorescence (EDXRF) spectrometry for elemental content evaluation in NP-containing agricultural samples. For Phaseolus vulgaris (common bean) seedlings treated with ZnO NP, CuO NP, and Fe₃O₄ NP, the limits of detection (LODs) were 0.4 mg kg⁻¹ for Zn and Cu and 0.6 mg kg⁻¹ for Fe after dry-ashing digestion, thus being suitable for NP oxide monitoring in seed priming. For submicron suspension fertilizers, Mn, Cu, and Zn were quantified as thin films after sample dilution. The LODs for Mn, Cu, and Zn were 0.09, 0.1, and 0.08 mg L⁻¹, respectively. Finally, for P. vulgaris plants exposed to 300-nm ZnO NP, we monitored P, S, K, Ca, and Zn directly in powdered leaves, whose LODs ranged from 1.3 to 27 mg kg⁻¹. No critical spectral interference was observed, and notable repeatability and suitable trueness were found in the cases of studies. EDXRF revealed itself a simple, fast, and reliable alternative to evaluate the elemental content in suspensions or the uptake of NP by plants.     

Elemental characterization of edible plants and soils in an abandoned mining region: assessment of environmental risk

The chemical concentrations of 11 elements in 6 species of edible plants grown in 7 soils, developed in different gossanous materials of the abandoned mine area of Sao Domingos, in southern Portugal, was measured by energy dispersive X‐ray fluorescence. The total fraction of elements in the soils from which the plants were sampled, was measured, using wavelength dispersive X‐ray fluorescence. The elemental content in bioavailable fraction was obtained by using three different leaching tests: DIN 38414‐S4, 1 M ammonium acetate and 0.005 M DTPA. Leachates were analyzed by Induced Coupled Plasma—Optical Emission Spectrometer (ICP‐OES) and Induced Coupled Plasma—Mass Spectrometer (ICP‐MS). The mineralogy of the same soils was evaluated by X‐ray diffraction to identify the species present. The results show that levels in plants can be hazardous especially for Pb and As. Important concentrations of Fe and K were also observed. A different uptake was observed in the several plants for the different elements. The highest assimilation of metals was observed in sampling points containing soluble sulfate salts. Copyright © 2011 John Wiley & Sons, Ltd.     

Determination of microelement distribution in different components of soil-plant systems

The leaves, stem, and roots of two types of shrubs (tea (Camellia sinensis) and sweet leaf (Sauropus androgynus)) and two types of herbs (vetiver grass (Vetiveria zizanioides L. Nash) and maize (Zea mays L)) and the Thucuc soil where the plants were growing were collected to be studied. The contents of 22 elements in the samples were determined by three methods: X-Ray fluorescence analysis (XRFA), gamma activation analysis (GAA), and the tracking method to study the distribution of these elements in plants and the soil-plant relationship. This study was carried out at the Flerov Laboratory of Nuclear Reactions (FLNR), Joint Institute for Nuclear Research (JINR), Dubna, Russia. The distribution of the elements in the soil-plant system was studied.     

Elemental characterization and source identification of the near-road PM2.5 using EDXRF in Chengdu,China

To characterize the elemental composition and source apportionment of aerosols in roadside area, particulate matters with aerodynamic diameter less than 2.5 μm (PM_2.5) were collected in close proximity to a road from September 2017 to February 2018 in downtown Chengdu, China. An energy-dispersive X-ray fluorescence spectrometer was used to quantify elemental constituents (Al, Si, S, K, Mn, Fe, Ni, Cu, Zn, As, and Pb) of PM_2.5 and was calibrated by in-house standards instead of commercial standards. The constructed calibration curves exhibited good linearity with all correlation coefficients greater than 0.98. The proposed calibration method proved to be reliable for the subsequent elemental analyses due to the satisfactory performance of u-score and precision that were validated by the certified reference materials (#2783). The results revealed that average PM_2.5 concentrations of 92.2 ± 45.6 and 113.2 ± 60.3 μg/m³ were respectively observed in autumn and in winter. The major trace elements identified were K, S, and Fe and the minor contributions were from Cu and As. Most crustal elements showed decline in winter except for K, and most anthropogenic elements showed increase in winter except for Ni. Using rotation factor analysis and cluster analysis based on the elemental dataset, four potential sources were identified: road dust, vehicular emissions, coal and biomass burning, and industrial emissions. This research will provide a better understanding of traffic-related PM_2.5 composition, and this can be used in the mitigation and prevention programs.     

Direct determination of mineral nutrients in soybean leaves under vivo conditions by portable X-ray fluorescence spectroscopy

A portable energy dispersive X-ray fluorescence (XRF) spectrometer furnished with an Rh X-ray tube was evaluated for the determination of macronutrients and micronutrients in soybean leaves (Glycine max L.). XRF instrumental parameters were optimized in a univariate way, and emission intensities were measured for 60 s and under vacuum for macronutrients, and during 180 s, under air, and 305 μm Al/25.4 μm Ti filter, for micronutrients. Fresh and dried leaves were irradiated, and it was possible to identify P, K, Ca, S, Mn, Fe, Cu, and Zn Kα emission lines. For comparative purpose, the samples were also microwave assisted, digested and analyzed by inductively coupled plasma optical emission spectrometry. In general, linear correlations between K, Ca, Mn, Fe, Cu, and Zn concentrations in the tested samples and the corresponding portable XRF (pXRF) intensities were obtained. The linear correlation coefficients (R²) ranged from 0.42 to 0.86. In addition, the detection limits were suitable for plant nutrient diagnosis. It is demonstrated that pXRF is a simple and powerful tool for analysis of plant materials.     

Nuclear microscopy of normal and necrotic skeletal muscle fibers: an intracellular elemental microanalysis

The in situ total elemental composition and elemental concentrations present in mouse soleus (type I) and gastrocnemius (type IIA) muscle fibers were analyzed by using nuclear microscopy (NM). Elemental changes in necrotic fibers, induced by intramuscluar injection with snake venom (Pseudechis australis), were also studied 3 h post-injection. Nuclear microscopy is a new method based on nuclear technology that utilizes the interaction between a million-electron-volt nuclear particle beam and the muscle sample (in the case of the present study). Elemental analysis was done at the parts per million (ppm) level of sensitivity on unfixed, rapidly frozen and unstained single fast- and slow-twitch muscle fibers with imaging capabilities of μm spatial resolution and in multi-elemental mode. In total, 12 different intracellular elements were mapped, co-localized and analyzed in single normal and necrotic skeletal muscle fibers from mice. Elements such as potassium, sulfur, phosphorus, chlorine and sodium were found in concentrations from 1000 to 18 000 ppm. Unlike conventional electron-probe X-ray microanalysis, NM also detected and analyzed the trace elements such as magnesium, calcium, iron and zinc that were found in concentrations of 50 to 1000 ppm. Other elements — copper, manganese and rubidium — were also detected in concentrations of less than 50 ppm. The trace elements calcium, iron and zinc were more abundant in the soleus than the gastrocnemius (the level of iron was statistically significant). Calcium, sodium and chlorine were significantly elevated in venom-induced necrotic soleus muscle fibers.     

Concentrations and sources of trace elements in particulate air pollution,Dar es Salaam,Tanzania, studied by EDXRF

Trace elements in near‐ground atmospheric aerosols were investigated in Dar es Salaam, Tanzania. Particles were collected at two sites, one urban and one rural, during two months with different meteorological conditions. The samplers, dichotomous impactors, segregate the particles into two size fractions, fine (PM_2.5, d_a < 2.5 µ m) and coarse (2.5 < d_a < 10 µ m). A sharp cyclone was used to sample finer particles (PM₁, d_a < 1 µ m). Meteorological parameters were also examined at both sites. An EDXRF spectrometer, based on three‐axial geometry, was used for quantitative elemental analysis. Concentrations of elements heavier than phosphorus were determined. Also, the content of black carbon on the filters was measured with a reflectometer. The elemental concentrations were compared with respect to season and geographical location in the city. The levels of different species in Dar es Salaam were also compared with similar data from other African and European countries. This showed low values of Pb with respect to the size of the city and no legislation on the use of leaded petrol, that often is the main source of lead. High values of Cl were also found, as would be expected in a coastal city. The coarse particles in the air, originating from soil, had a different composition in Dar es Salaam than in Gaborone, Botswana, and the concentration of black carbon was higher than in other cities. On the basis of the data collected, source assignments were made and the following sources found; sea‐spray, soil, city road dust, biomass burning, industries and traffic. Comparing the concentrations of different elements in PM_2.5 and PM₁ revealed that black carbon, Zn, Pb, K and Br are present only in the smallest particles. Copyright © 2004 John Wiley & Sons, Ltd.