Human hair analysis by PIXE: Pattern recognition of trace element composition

The feasibility is explored of classifying human hair specimens according to their trace metal composition as determined by PIXE. Protons of 3.5 MeV were used to analyse 150 samples by energy-dispersive spectrometry using a Si(Li) detector. The methods of the Minimal Spanning Tree and Non-Linear Mapping were used to establish correlation among the specimens. As a result of distinct groupings obtained by these methods it was inferred that these techniques could usefully be applied to environmental pollution studies.     

Untargeted GC-MS Metabolomics applied to wild leaves and callus produced by plant tissue culture of Hibiscus sabdariffa L.

Hibiscus sabdariffa L. is a naturalized medicinal species in Brazil commonly called a “vinagreira” and is a member of the Malvaceae Juss. family, which has a rich potential of bioactive compounds presenting extracts with antioxidant, antibacterial, anti-inflammatory, hepatoprotective, antiviral, antidiabetic, and antiobesity, among others. The production of secondary metabolites of medicinal plants using biotechnological tools such as the culture of callus of plant tissues is increasingly being used to produce high-quality compounds under in vitro conditions. From this perspective, the objective of this work was to analyze the chemical compounds of the leaves and callus culture of H. sabdariffa using techniques of Gas Chromatography Coupled to the Mass Spectrum (GC-MS),. The analysis methodology used consisted of removal of liposoluble compounds, acid hydrolysis, and derivatization, all stages were submitted to ultrasonic-assisted agitation, using a reduced amount of biomass. Based on the results obtained in the study, a total of 38 metabolites identified by GC-MS analysis can be observed. Among the identified substances, protocatechuic acid (26A) stands out as the main constituent, with a relative abundance of 26.86% and 16.68% for leaves and callus of H. sabdariffa, respectively. The principal component analysis (PCA) allowed the discrimination of the chemical composition of each sample, being useful for the observation and detection of the compounds trends patterns. The analysis of the hierarchical group combined with the heat map represented the visual relationship between the samples of the data set indicating the values of higher and lower concentrations of chemical compounds respectively, confirming that protocatechuic acid is the most abundant, for the leaves and callus of H. sabdariffa, followed by eicosanoid and isocitric acid, produced only in callus. It was concluded that the GC-MS technique combined with chemometric tools, helped identify the diversity of the compounds present in the leaves and callus of H. sabdariffa and that callus culture enables the production of bioactive compounds continuously and uniformly in a controlled environment and free of contamination.     

Applications of total reflection X-ray fluorescence spectrometry in trace element and surface analysis

Total reflection X-ray fluorescence spectrometry (TXRF) is presented as a genuine surface analytical technique. Its low information depth is shown to be the characteristic feature differentiating it from other energy dispersive X-ray fluorescence methods used for layer and surface analysis. The surface sensitivity of TXRF and its analytical capability together with the limitations of the technique are discussed here using typical applications including the contamination control of silicon wafers, thin layer analysis and trace element determination. For buried interfaces and implantation depth profiles in silicon a combination of TXRF and other techniques has been applied successfully. The TXRF method has the particular advantage of being calibrated without the need for standards. This feature is demonstrated for the example of the element arsenic.     

Proton induced X-ray emission (PIXE) technique for determining multi-element composition of transformed hairy root cultures of Boerhaavia diffusa L.: an important medicinal herb

Therapeutically important inorganic elements in Agrobacterium rhizogenes-mediated genetically transformed hairy root cultures (HRCs) of a pharmaceutically significant herb Boerhaavia diffusa were quantified using proton induced X-ray emission technique. This was compared with that of roots from the naturally grown donor plant. Two macro-elements (Ca & K) and eight different trace elements namely V, Cr, Mn, Fe, Co, Cu Zn, and Ni were detected and their content was determined. In HRCs of a transformed rhizoclone, calcium and potassium had values which were significantly higher than that of in vivo roots. The concentrations of several trace elements, which are known to have a positive implication in human healthcare, were found to be either comparable (Fe) to that in the natural root samples or higher (Mn, Zn, Cr, Cu, Co) in the transformed rhizoclone. The genetically transformed HRCs can thus serve as a fast-proliferating renewable resource of medicinally useful minerals targeting specific diseases.     

Sound-producing sand in Japan: major element composition and its minerals determined by X-ray diffraction and X-ray fluorescence.

The major element composition, including two kinds of clay minerals and moisture content of sound-producing sand are reported for the first time. Sand from 33 beaches in Japan has been found to make sound. Ten sound-producing beaches were selected to compare with silent beach sand. Both sound-producing sand and silent beach sand are mostly composed of quartz and feldspar. The range of SiO2 content of sound-producing sand is not different from silent sand samples. This indicates that a high quartz content is not necessary to produce sound, although more than 60 weight percent of quartz is necessary. One silent sand recovered its sound after a 3.5 percent HNO3 treatment. Also, a small portion of clay minerals was found. A clean grain surface is a necessary factor for sand to produce sound. Illite was found in all silent sand samples.     

Development of a new approach to trace element analysis using neutron activation followed by high resolution X-ray spectrometry

The interference of beta particles with the measurement of X-rays with Si(Li) detectors, is eliminated by the use of magnetic fields. The latter defect the beta particles preventing them to reach the detector, but have no effect on the X-rays to be measured. Thus the high background which obscures the X-ray peaks of low and medium Z elements is reduced to a minimum and the resolution of the detector restored to ist normal value. As a result the X-ray peaks may be accurately integrated. Several experiments which show the usefulness of the method are discussed. This work was supported by the U.S.-Israel Binational Science Foundation.     

Measurement of trace element concentration in a metal matrix using total reflection X-ray fluorescence spectrometry

Total reflection X-ray fluorescence spectroscopy (TXRF) has been used in combination with synchrotron radiation in order to determine detection limits and lowest limits of concentration of trace elements in metal matrices. Two applications on irradiated material are described, where the TXRF method has some advantages, as compared to other detection methods, because only few micrograms of material is needed for the measurements. The first application is devoted to radiation damage studies on first wall material of future fusion reactors. Therefore, metal foils were irradiated with 590 MeV protons at PSI and the transmutational elements produced in the foils were measured. The second application is the assessment of radiation damage of core components in a nuclear power plant, e.g. the reactor pressure vessel. This is performed by the determination of the fast neutron fluence on the components using an activation reaction of ⁹³Nb which is a trace element in most reactor steels. Detection limits of a few picograms have been found in the experiments.     

Solid-liquid extraction as a preconcentration technique in trace element analysis Extraction of trace impurities from metal chlorides

Microgram quantities of iron, cobalt, copper, zinc and cadmium are extracted with various aqueous, organic and mixed solvents from chlorides of sodium, potassium, nickel, cadmium, barium and lead prepared by evaporation of aqueous sample solutions. An ultrasonic field accelerates the extraction, and satisfactory trace recoveries and separation factors are achieved in several systems within a reasonable time. The application to a polarographic determination and a two-stage separation technique are also described.     

Determination of trace element pathways in a petroleum distillation unit by instrumental neutron activation analysis

The concentrations of 11 trace and minor elements (Na, Al, S, Cl, Ca, V, Mn, Ni, As, Br, I) have been measured by instrumental neutron activation analysis in a sample of crude oil from Venezuela, and in 7 of its distillates and in the final residue produced in a primary distillation unit. Concentrations range from 0.5 ppb to 2.0%. The elements have been classified in 4 categories on the basis of their distributions among the fractions analyzed. The results on concentrations have also been used to establish elemental balances in the distillation unit studied operating under steady-state conditions. Only S and V have been found to give rise to losses by emission.     

Fractionation analysis of trace metals in humic substances of soils irrigated with wastewater in Central Mexico by particle induced X-ray emission

The Mezquital Valley in Central Mexico has received wastewater from Mexico City for nearly 100 years. Wastewater brings in organic matter and nutrients but also trace metals. Humic substances, the main components of organic soil matter, are responsible for retaining and regulating the mobility of trace metals in soils. In this study, humic substances were extracted from the soil and separated into distinct fractions (humic acids, fulvic acids and humins). The particle induced X-ray emission (PIXE) technique was applied to determine the metal content in bulk soil as well as in humic acids and fulvic acids not soluble in H₃PO₄. In order to assess whether the long-term input of organic matter and metals modifies the metal association with these humic substances, parcels irrigated for three time periods (5, 47 and 89 years) were selected for this study. It was observed that metals such as Zn and Cu are mainly associated with the humic acids. Fulvic acids retain mainly Cr while Pb is distributed among humic and fulvic acids. It was also observed that in general, metal retention by humic substances increases with irrigation time. Depth also affects metal association with the humic substances.     

Phytochemical analysis of the essential oil of Thymus serpyllum L. growing wild in Estonia

Variations in the essential oil composition of Thymus serpyllum L., growing wild in Estonia (33 samples) and in some other countries (Russia, Latvia and Armenia, seven samples) were determined. The oil were obtained from Estonia (46 samples) in yields 0.6-4.4 and 1.9-8.2 mL kg(-1) in other countries. The T. serpyllum herb grown in Estonia usually did not confirmed to the EP standard in the aspect of the essential oil contents (3.0 mL kg(-1)). Variations in the essential oil composition of wild thyme were studied using capillary gas chromatographic methods. A total of 94 components were identified. Thymol and carvacrol, mentioned in literature as principial components, are not the main components of the essential oil of wild thyme growing in Estonia. (E)-nerolidol, caryophyllene oxide, myrcene and borneol chemotypes of wild thyme drug are distinguishable. The chemical composition of samples from Russia, Latvia and Armenia is very variable.     

Wet mineralization of organic matrices in glassy carbon vessels in a pressure-bomb system for trace element analysis

Glassy carbon (Sigradur G(R)) is thermally stable up to 600 degrees under atmospheric conditions and has proved to be substantially resistant to many decomposition agents at temperatures up to 250 degrees . It can, therefore, substitute for PTFE vessels in a pressure-bomb device for the wet decomposition of organic and inorganic substances with, e.g., nitric, chloric or hydrofluoric acid or mixtures thereof, in the determination of trace elements. The mineralization can be carried out at temperatures up to 50 degrees higher than with PTFE vessels, which are limited to a maximum of 170 degrees . The higher decomposition temperature, which results in a higher oxidation potential, considerably shortens the decomposition time. On account of the lower content of impurities, particularly of Hg, Ag, Bi, Cd, Se, Te and Sb, the results are more accurate than those obtained with PTFE vessels, if these elements are to be determined in the ng/g range in the resulting solution.     

Comparative analysis of the composition of the essential oil from the shoots,leaves and stems the wild Ledum palustre L. from Estonia

The aerial parts of Ledum palustre L. were collected near to Pudisoo River, Harju country, Estonia, in September 2007. The simultaneous distillation and extraction micro-method (SDE) was used to isolate the essential oil from the plant's samples. The capillary gas chromatographic (GC/FID) analysis was applied to the identification of oil components and determination of their content in the oil. The yield of oil from the leaves was 0.92%, from the stems, 0.24% and from the shoots, 0.78%. A total of 68 constituents, accounting for over 95% of the total oil yield, were identified in the oils.     

Chemical composition of volatile and fixed oils from of Salvia argentea L. (Lamiaceae) growing wild in Sicily

The chemical compositions of the essential oil and of the non-polar extracts (petroleum ether, dichloromethane) of the aerial parts (flowers, leaves and stems) of Salvia argentea L. were determined by GC-FID and gas chromatography–mass spectrometry analysis. 14-Hydroxy-α-humulene (40.1%) was recognised as the main constituents of the essential oil of S. argentea, together with 1,3,8-p-menthatriene (12.1%), globulol (7.4%) and β-sesquiphellandrene (5.8%). Tritriacontane (9.9% and 14.1%), heptacosane (8.4% and 10.5%), hentriacontane (8.3% and 10.9%), tetradecanal (8.4% and 10.2%) and methyldotriacontane (7.9% and 7.6%) were recognised as the main constituents of the extracts in petroleum ether and dichloromethane, respectively, whereas methyl linolenate (36.6% and 13.5%) and methyl myristoleate (10.5% and 18.5%) were recognised as the main constituents of the methylated extracts.     

A new iridoid glycoside from galium verum L. First X-ray analysis of a tricyclic iridoid glycoside

V₂ iridoid (I) was isolated from the overground parts of the blooming plant and its complete structure has been established by spectroscopic and X-ray diffraction methods.     

Essential oil composition and antioxidant activity of Stachys sylvatica L. (Lamiaceae) from different wild populations in Kosovo

Leaves and inflorescences of Stachys sylvatica L. (Lamiaceae) were collected from three different wild populations in Kosovo to study the natural variation of the chemical composition of essential oils, total flavonoids, total phenolics and the antioxidant activity. Essential oils were obtained by steam distillation and analysed by GC-FID and GC-MS, whereas total flavonoids, total phenolics and antioxidant activities were determined by spectrophotometric methods. Yields of essential oils ranged from 0.001% to 0.007% (v per dry weight). Twenty-eight volatile constituents were identified. The main constituents were α-pinene, β-pinene and germacrene-D. Total phenolics ranged from 39.3 to 70.8?mg?g?1 dry mass, whereas total flavonoid content ranged from 30.44 to 70.63?mg?g?1 dm. The antioxidant activity, as measured by the DPPH method, exhibited a rather high degree of activity ranging from 25.5% to 57.2%, whereas the FRAP antioxidant activity showed a lower variability and ranged from 93 to 133.4?mg?g?1 dm.     

Chemical composition of the essential oil from Thapsia garganica L. (Apiaceae) grown wild in Sicily and its antimicrobial activity

In this study, the chemical composition of the essential oil from flowers and leaves of Thapsia garganica L. collected in Sicily was evaluated by GC and GC–MS. The main components of T. garganica flower oil (T.f.) were chamazulene (58.3%), humulene oxide II (9.0%), tricosane (8.2%) and pentacosane (8.2%). Also the oil from leaves (T.l.) was characterised by high content of chamazulene (49.2%). Other abundant metabolites were 1,4-dimethylazulene (18.5%), (E)-phytol (6.3%) and neophytadiene (5.1%). The comparison with other studied oils of genus Thapsia is discussed. Antimicrobial activity against several micro-organisms, including some ones infesting historical art craft, was also determined.     

Automated analysis of SEM X-ray spectral images: a powerful new microanalysis tool.

Spectral imaging in the scanning electron microscope (SEM) equipped with an energy-dispersive X-ray (EDX) analyzer has the potential to be a powerful tool for chemical phase identification, but the large data sets have, in the past, proved too large to efficiently analyze. In the present work, we describe the application of a new automated, unbiased, multivariate statistical analysis technique to very large X-ray spectral image data sets. The method, based in part on principal components analysis, returns physically accurate (all positive) component spectra and images in a few minutes on a standard personal computer. The efficacy of the technique for microanalysis is illustrated by the analysis of complex multi-phase materials, particulates, a diffusion couple, and a single-pixel-detection problem.     

Inter-population variability of terpenoid composition in leaves of Pistacia lentiscus L. from Algeria: a chemoecological approach

Three different altitudes were selected to study the variability of terpenoid composition from leaves of female plants of Pistacia lentiscus L. throughout the elevation gradient. GC-MS analyses showed that terpenoid contents change with altitude. Forty nine compounds were identified with a high interpopulation variability for low- and midaltitude sites that also exhibited the same major components when data were expressed on dry weight basis. However, Two-Way-ANOVA followed by Tukey's post hoc test showed that monoterpene hydrocarbons increased with elevation, giving values of 21.7, 37.5 and 221.5 μg g?1 dw for low- mid- and highlands, respectively. On the other hand, applying P.C.A. with data expressed in percentage of the chromatogram of the volatile extract led to the identification of three chemotypes associated with altitudinal levels. In highlands (Group I), the major compounds were β-caryophyllene (12%), δ-cadinene (9.3%) and a-pinene (6.3%) while in midlands (Group II), β-caryophyllene (11.5%), δ-cadinene (8.6%) and caryophyllene oxide (6.8%) were the main components. In lowlands (Group III) δ-cadinene (10.9%), cubebol (10.5%) and β-bisabolene (7.7%) were chiefly present. Hence, the involvement of genetic factors, temperature and drought in the chemical polymorphism of P. lentiscus associated with elevation is discussed in this report.