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Sample records for fluorescence analysis determination

  1. Fluorescence uranium determination

    Fernandez Cellini, R.; Crus Castillo, F. de la; Barrera Pinero, R.

    1960-01-01

    An equipment for analysis of uranium by fluorescence was developed in order to determine it at such a low concentration that it can not be determined by the most sensible analytical methods. this new fluorimeter was adapted to measure the fluorescence emitted by the phosphorus sodium fluoride-sodium carbonate-potasium carbonate-uranyl, being excited by ultraviolet light of 3,650 A the intensity of the light emitted was measure with a photomultiplicator RCA 5819 and the adequate electronic equipment. (Author) 19 refs

  2. Significant improvement of accuracy and precision in the determination of trace rare earths by fluorescence analysis

    Ozawa, L.; Hersh, H.N.

    1976-01-01

    Most of the rare earths in yttrium, gadolinium and lanthanum oxides emit characteristic fluorescent line spectra under irradiation with photons, electrons and x rays. The sensitivity and selectivity of the rare earth fluorescences are high enough to determine the trace amounts (0.01 to 100 ppM) of rare earths. The absolute fluorescent intensities of solids, however, are markedly affected by the synthesis procedure, level of contamination and crystal perfection, resulting in poor accuracy and low precision for the method (larger than 50 percent error). Special care in preparation of the samples is required to obtain good accuracy and precision. It is found that the accuracy and precision for the determination of trace (less than 10 ppM) rare earths by fluorescence analysis improved significantly, while still maintaining the sensitivity, when the determination is made by comparing the ratio of the fluorescent intensities of the trace rare earths to that of a deliberately added rare earth as reference. The variation in the absolute fluorescent intensity remains, but is compensated for by measuring the fluorescent line intensity ratio. Consequently, the determination of trace rare earths (with less than 3 percent error) is easily made by a photoluminescence technique in which the rare earths are excited directly by photons. Accuracy is still maintained when the absolute fluorescent intensity is reduced by 50 percent through contamination by Ni, Fe, Mn or Pb (about 100 ppM). Determination accuracy is also improved for fluorescence analysis by electron excitation and x-ray excitation. For some rare earths, however, accuracy by these techniques is reduced because indirect excitation mechanisms are involved. The excitation mechanisms and the interferences between rare earths are also reported

  3. X-ray fluorescence analysis for trace element determination in foodstuff chemistry

    Wildanger, W.

    The physical fundamentals of X-ray fluorescence analysis are given and the routine spectrometers described. The basic principles are given of analytical methods used in qualitative and quantitative fluorescence analyses. Examples are given of the use of the method in a number of fields and the possibility and usefulness is discussed for the determination of trace elements in foodstuffs. The preparation of samples, preliminary concentration of components and calibration methods are discussed. (M.K.)

  4. Computer-assisted sperm morphometry fluorescence-based analysis has potential to determine progeny sex

    Pilar Santolaria

    2016-01-01

    Full Text Available This study was designed to determine the ability of computer-assisted sperm morphometry analysis (CASA-Morph with fluorescence to discriminate between spermatozoa carrying different sex chromosomes from the nuclear morphometrics generated and different statistical procedures in the bovine species. The study was divided into two experiments. The first was to study the morphometric differences between X- and Y-chromosome-bearing spermatozoa (SX and SY, respectively. Spermatozoa from eight bulls were processed to assess simultaneously the sex chromosome by FISH and sperm morphometry by fluorescence-based CASA-Morph. SX cells were larger than SY cells on average (P < 0.001 although with important differences between bulls. A simultaneous evaluation of all the measured features by discriminant analysis revealed that nuclear area and average fluorescence intensity were the variables selected by stepwise discriminant function analysis as the best discriminators between SX and SY. In the second experiment, the sperm nuclear morphometric results from CASA-Morph in nonsexed (mixed SX and SY and sexed (SX semen samples from four bulls were compared. FISH allowed a successful classification of spermatozoa according to their sex chromosome content. X-sexed spermatozoa displayed a larger size and fluorescence intensity than nonsexed spermatozoa (P < 0.05. We conclude that the CASA-Morph fluorescence-based method has the potential to find differences between X- and Y-chromosome-bearing spermatozoa in bovine species although more studies are needed to increase the precision of sex determination by this technique.

  5. Determination of small amounts of aluminum in iron and steel by x-ray fluorescence analysis

    Ito, Minao; Sato, Shoki; Narita, Masanao

    1981-01-01

    The accuracy of X-ray fluorescence analysis for determining aluminum in steel is generally poor when the aluminum content is below 0.1%. In this study, it is confirmed that the existence of inhomogeneous acid-insoluble aluminum causes the poor accuracy of X-ray fluorescence analysis. The accuracy can be improved by adding granular ferro-zirconium to molten steel when sampling. By using this method, the accuracy of determining aluminum was 0.0024% for low alloy steels and 0.0022% for stainless steels as the standard deviation obtained for a series of differences between an analytical result and a standard value. Corrections for overlapping of the chromium spectrum, and for absorption and enhancement effects of co-existent elements are not necessary for the analysis of low alloy steels, whereas these corrections are necessary for the analysis of stainless steels. (author)

  6. Development of unified X-ray fluorescent analysis to determine rhenium content in multicomponent oxide compositions

    Drobot, D.V.; Belyaev, A.V.; Kutvitskij, V.A.; Rysev, A.P.

    1999-01-01

    A procedure to prepare rhenium-containing glass-like specimens on the basis of bismuth and boron oxides is proposed. The glasses produced are studied by X-ray fluorescent analysis and routine spectrometric thiocyanate analysis. The results make it possible to determine rhenium in oxide mixtures in the range of its content 0.01 - 10% with S r = 0.03 [ru

  7. The determination of lanthanum and lanthanide elements by means of X-ray fluorescence analysis

    Kuelcue, N.

    1982-01-01

    The quantitative analysis of all lanthanide elements (except Pm) was carried out concurrently using X-ray fluorescence analysis. By choice of suitable preparative methods (thin layer samples prepared by pipetting solutions onto filter paper) and use of an internal standard (Sr) it was possible to obtain linear calibration curves up to high concentrations in the solution (85 g/l) and to suppress disturbances caused by absorption and secondary fluorescence. A correction procedure was developed for reflection superimpositions in the L-spectra of the lanthanide elements which, through selection of the most favourable reflections for analysis, permitted concurrent determination of all 14 elements. Main and secondary constitutents can be analysed whereas enrichment is required for trace analysis. Under routine usage the actual limits of detection range from 3 to 17 μg/cm 2 or alternatively 0.3 to 1.7 mg/ml. (orig.) [de

  8. Determination of potassium concentration in organic samples by means of x-ray fluorescence analysis

    Soto Moran, R.L.; Szgedi, S.

    1993-01-01

    By means of x-ray fluorescence analysis and the inner standard method using KH 2 PO 4 as the added chemical compound, potassium concentration of roots, stems , leaf, flowers and grains from Quinua (Chenopodium Quinoa Willd). which was previously treated with a nitrogen ed fertilizers has been determined taking into account the increasing effect the average atomic number due to used standard. Experimental errors are lower than 10 %

  9. Computer-assisted sperm morphometry fluorescence-based analysis has potential to determine progeny sex.

    Santolaria, Pilar; Pauciullo, Alfredo; Silvestre, Miguel A; Vicente-Fiel, Sandra; Villanova, Leyre; Pinton, Alain; Viruel, Juan; Sales, Ester; Yániz, Jesús L

    2016-01-01

    This study was designed to determine the ability of computer-assisted sperm morphometry analysis (CASA-Morph) with fluorescence to discriminate between spermatozoa carrying different sex chromosomes from the nuclear morphometrics generated and different statistical procedures in the bovine species. The study was divided into two experiments. The first was to study the morphometric differences between X- and Y-chromosome-bearing spermatozoa (SX and SY, respectively). Spermatozoa from eight bulls were processed to assess simultaneously the sex chromosome by FISH and sperm morphometry by fluorescence-based CASA-Morph. SX cells were larger than SY cells on average (P potential to find differences between X- and Y-chromosome-bearing spermatozoa in bovine species although more studies are needed to increase the precision of sex determination by this technique.

  10. Determination of minor and trace elements in kidney stones by x-ray fluorescence analysis

    Srivastava, Anjali; Heisinger, Brianne J.; Sinha, Vaibhav; Lee, Hyong-Koo; Liu, Xin; Qu, Mingliang; Duan, Xinhui; Leng, Shuai; McCollough, Cynthia H.

    2014-03-01

    The determination of accurate material composition of a kidney stone is crucial for understanding the formation of the kidney stone as well as for preventive therapeutic strategies. Radiations probing instrumental activation analysis techniques are excellent tools for identification of involved materials present in the kidney stone. In particular, x-ray fluorescence (XRF) can be very useful for the determination of minor and trace materials in the kidney stone. The X-ray fluorescence measurements were performed at the Radiation Measurements and Spectroscopy Laboratory (RMSL) of department of nuclear engineering of Missouri University of Science and Technology and different kidney stones were acquired from the Mayo Clinic, Rochester, Minnesota. Presently, experimental studies in conjunction with analytical techniques were used to determine the exact composition of the kidney stone. A new type of experimental set-up was developed and utilized for XRF analysis of the kidney stone. The correlation of applied radiation source intensity, emission of X-ray spectrum from involving elements and absorption coefficient characteristics were analyzed. To verify the experimental results with analytical calculation, several sets of kidney stones were analyzed using XRF technique. The elements which were identified from this techniques are Silver (Ag), Arsenic (As), Bromine (Br), Chromium (Cr), Copper (Cu), Gallium (Ga), Germanium (Ge), Molybdenum (Mo), Niobium (Nb), Rubidium (Rb), Selenium (Se), Strontium (Sr), Yttrium (Y), Zirconium (Zr). This paper presents a new approach for exact detection of accurate material composition of kidney stone materials using XRF instrumental activation analysis technique.

  11. Statistical Analysis of Bending Rigidity Coefficient Determined Using Fluorescence-Based Flicker-Noise Spectroscopy.

    Doskocz, Joanna; Drabik, Dominik; Chodaczek, Grzegorz; Przybyło, Magdalena; Langner, Marek

    2018-06-01

    Bending rigidity coefficient describes propensity of a lipid bilayer to deform. In order to measure the parameter experimentally using flickering noise spectroscopy, the microscopic imaging is required, which necessitates the application of giant unilamellar vesicles (GUV) lipid bilayer model. The major difficulty associated with the application of the model is the statistical character of GUV population with respect to their size and the homogeneity of lipid bilayer composition, if a mixture of lipids is used. In the paper, the bending rigidity coefficient was measured using the fluorescence-enhanced flicker-noise spectroscopy. In the paper, the bending rigidity coefficient was determined for large populations of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine and 1,2-dioleoyl-sn-glycero-3-phosphocholine vesicles. The quantity of obtained experimental data allows to perform statistical analysis aiming at the identification of the distribution, which is the most appropriate for the calculation of the value of the membrane bending rigidity coefficient. It has been demonstrated that the bending rigidity coefficient is characterized by an asymmetrical distribution, which is well approximated with the gamma distribution. Since there are no biophysical reasons for that we propose to use the difference between normal and gamma fits as a measure of the homogeneity of vesicle population. In addition, the effect of a fluorescent label and types of instrumental setups on determined values has been tested. Obtained results show that the value of the bending rigidity coefficient does not depend on the type of a fluorescent label nor on the type of microscope used.

  12. Metals determination in wood treated by synchrotron radiation X-ray fluorescence analysis

    Vives, Ana Elisa Sirito de; Medeiros, Jean Gabriel da Silva; Tomazello Filho, Mario

    2005-01-01

    The paper describes the use of X-Ray fluorescence analysis for distribution and quantification of metals in the hardwood (Eucalyptus sp) and softwood (Pinus sp) treated with CCA (copper-chromium-arsenic). The sapwood/heartwood for hardwood sample and the growth-rings for softwood sample were analyzed. The samples were scanned in 320 mm steps in the vertical direction. For excitation of the elements a white beam synchrotron radiation of ∼ 320 x 180 mm was employed and for the X-ray detection a Si(Li) semiconductor detector. The elements K, Ca, Cr, Mn, Cu, Zn and As were determined. Fundamental parameters were used to quantify the elements concentrations. (author)

  13. Metals determination in wood treated by synchrotron radiation X-ray fluorescence analysis

    Vives, Ana Elisa Sirito de [Universidade Metodista de Piracicaba (UNIMEP), Santa Barbara D' Oeste, SP (Brazil). Faculdade de Engenharia, Arquitetura e Urbanismo]. E-mail: aesvives@unimep.br; Silva, Richard Maximiliano da Cunha [Centro de Energia Nuclear na Agricultura, Piracicaba, SP (Brazil)]. E-mail: maxcunha@cena.usp.br; Medeiros, Jean Gabriel da Silva; Tomazello Filho, Mario [Sao Paulo Univ., Piracicaba, SP (Brazil). Escola Superior de Agricultura Luiz de Queiroz]. E-mail: jeangm@esalq.usp.br; mtomazel@esalq.usp.br; Moreira, Silvana [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia Civil, Arquitetura e Urbanismo]. E-mail: Silvana@fec.unicamp.br; Zucchi, Orgheda Luiza Araujo Domingues [Sao Paulo Univ., Ribeirao Preto, SP (Brazil). Faculdade de Ciencias Farmaceuticas]. E-mail: olzucchi@fcfrp.usp.br; Barroso, Regina Cely [Universidade do Estado, Rio de Janeiro, RJ (Brazil)]. E-mail: cely@uerj.br

    2005-07-01

    The paper describes the use of X-Ray fluorescence analysis for distribution and quantification of metals in the hardwood (Eucalyptus sp) and softwood (Pinus sp) treated with CCA (copper-chromium-arsenic). The sapwood/heartwood for hardwood sample and the growth-rings for softwood sample were analyzed. The samples were scanned in 320 mm steps in the vertical direction. For excitation of the elements a white beam synchrotron radiation of {approx} 320 x 180 mm was employed and for the X-ray detection a Si(Li) semiconductor detector. The elements K, Ca, Cr, Mn, Cu, Zn and As were determined. Fundamental parameters were used to quantify the elements concentrations. (author)

  14. Determination of Fe and Zn in healing plants by radionuclide X-ray fluorescence analysis

    Harangozo, M.; Toelgyessy, J.; Tomecek, O.; Ruzicka, I.; Cejpek, K.

    1999-01-01

    Radionuclide X-ray fluorescence method was used for the determination of Fe and Zn in healing plants (Sage, Peppermint, Stinging, Common Agrimony, Milfoil, Ribwort, Tansy, White Dead-Nettle). 238 Pu exciting source and Si/Li semiconductor detector were used for the determination. (author)

  15. [Determination of H2S in Rat Intestinal Perfusion Solution Based on Fluorescence Analysis].

    Hou, Jun-feng; Li, Xin-xia; Shen, Xue-ru; Huojia, Miliban; Guan, Ming

    2015-08-01

    Under alkaline conditions, Fluorescein mercury has strong fluorescence, however, when it met S(2-), its fluorescence would quench, in view of the above, a fluorescence method for determination of H2S in biological samples was established. In the 0.1 mol · L(-1) NaOH dilution, when the concentration of fluorescein Mercury and Na2S was 5.0 × 10(-5) and 1.0 × 10(-5) mol · L(-1) respectively, the fluorescence intensity of system was determined at 522 nm. The results showed that, at the range of 4.0 × 10(-7)~2.0 × 10(-6) mol · L(-1), the concentration decreasing of H2S and fluorescence intensity had good linear relationship, r=0.9980, the RSD of precision test was 4.59% (n=7), the detection limit was 3.5 × 10(-8) mol · L(-1), the content of H2S in the sample were 1.01 × 10(-6) and 1.15 × 10(-6) mol · L(-1), and the recovery rate was 95.8%~101.0%, the method has the advantages of simple operation, high sensitivity, good selectivity, can accurately determine of H2S in intestinal perfused solution, and provides the basis for the determination of endogenous H2S.

  16. Moessbauer spectroscopy and X-ray fluorescence analysis in studies for determinate the sources of several prehispanic objects

    Arriola S, H.; Ramos R, P.; Castro V, P.; Jimenez R, A.; Flores D, F.; Garcia Moreno C, C.

    1980-01-01

    A study by the Moessbauer effect and X-ray fluorescence analysis of the mexican prehispanic ceramic specimens is presented. Several iron compounds of the ceramics are determined, the different iron compounds indicate different sources of the clays, and different forms of ovens used with them, this compounds are identified by the differents oxidation states of the magnetic iron Fe 3+ , Fe 2+ . (author)

  17. Use of X-ray fluorescence analysis for the determination of hafnium in zircalloys

    Sato, I.M.; Salvador, V.L.R.; Lordello, A.R.

    1985-01-01

    The determination of hafnium at trace levels (ppm) in the presence of zirconium by X-ray fluorescence technique is presented. The samples were prepared in the form of double-layer pellets, with boric acid as the binding material. The most sensitive first order line of hafnium HfLα (0.157 nm), which is used analyticaly, has approximately 67% overlapping with second order line of zirconium ZrKα 1 , (0.079 nm). As the excitation potencial of zirconium is larger than hafnium, the best condition was selected, so that the interference of zirconium intensity would not be significant in hafnium analytical line. The method allowed the determination of hafnium above 5.0 ppm (LLd = 1.5 ppm) with an accuracy of less than 10%. (Author) [pt

  18. Development of image analysis for graphite pore-structure determination using fluorescence techniques

    Stephen, W.J.; Bowden, E.A.T.; Wickham, A.J.

    1983-03-01

    The use of image analysis to assess the pore structure of graphite has been developed to the point at which it may be considered available for routine use. A definitive pore structure in terms of the geometry-independent ''characteristic pore dimension'' is derived from the computer analysis of polished specimens whose open-pore structure has been impregnated with bismuth or a fluorescent epoxy resin, with the very small pores identified separately by mercury porosimetry as in the past. The pore-size distributions obtained from these combined techniques have been used successfully to predict the corrosion rates of nine graphites, of widely differing pore structure, in a variety of gas compositions and, indirectly, to confirm appropriate mean ranges and rate constants for the reaction of the oxidising species in these gas mixtures. The development of the fluorescent-impregnant technique is discussed in detail and its use is justified in preference to ''traditional'' methods. Further possible refinements are discussed, including the eventual aim of obtaining a computer prediction of the future oxidation behaviour of the graphite directly from the image analyser. (author)

  19. Metals determination in coffee sample by total reflection X-ray fluorescence analysis (TXRF)

    Vives, Ana Elisa Sirito de

    2005-01-01

    The objective of this study was to evaluate the inorganic concentration in five brands of coffee, three of them nationally marketed and the others of an exportation kind. The samples were prepared by infusion with deionized water. To carry out the calibration, standard solutions were prepared with different concentrations of Al, Si, K, Ca, Ti, Cr, Fe, Ni, Zn and Se. The measurements were carried out using a white beam of synchrotron radiation for excitation and a Si (Li) semiconductor detector for detection. By employing Synchrotron Radiation Total Reflection X-Ray Fluorescence Analysis (SR-TXRF) it was possible to evaluate the concentrations of P, S, Cl, K, Ca, Mn, Fe, Cu, Zn, Rb and Ba. The detection limits for 300 s counting time were in the range of 0.03 (Ca) to 30 ng.g -1 (Rb), respectively. (author)

  20. Metals determination in coffee sample by total reflection X-ray fluorescence analysis (TXRF)

    Vives, Ana Elisa Sirito de [Universidade Metodista de Piracicaba (UNIMEP), Santa Barbara D' Oeste, SP (Brazil). Faculdade de Engenharia, Arquitetura e Urbanismo]. E-mail: aesvives@unimep.br; Moreira, Silvana [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia Civil, Arquitetura e Urbanismo]. E-mail: Silvana@fec.unicamp.br; Brienza, Sandra Maria Boscolo [ Universidade Metodista de Piracicaba (UNIMEP), Piracicaba, SP (Brazil). Faculdade de Ciencias Matematicas, da Natureza e de Tecnologia da Informacao]. E-mail: sbrienza@unimep.br; Zucchi, Orgheda Luiza Araujo Domingues [Sao Paulo Univ., Ribeirao Preto, SP (Brazil). Faculdade de Ciencias Farmaceuticas]. E-mail: olzucchi@fcfrp.usp.br; Nascimento Filho, Virgilio Franco do [Centro de Energia Nuclear na Agricultura (CENA), Piracicaba, SP (Brazil)]. E-mail: virgilio@cena.usp.br

    2005-07-01

    The objective of this study was to evaluate the inorganic concentration in five brands of coffee, three of them nationally marketed and the others of an exportation kind. The samples were prepared by infusion with deionized water. To carry out the calibration, standard solutions were prepared with different concentrations of Al, Si, K, Ca, Ti, Cr, Fe, Ni, Zn and Se. The measurements were carried out using a white beam of synchrotron radiation for excitation and a Si (Li) semiconductor detector for detection. By employing Synchrotron Radiation Total Reflection X-Ray Fluorescence Analysis (SR-TXRF) it was possible to evaluate the concentrations of P, S, Cl, K, Ca, Mn, Fe, Cu, Zn, Rb and Ba. The detection limits for 300 s counting time were in the range of 0.03 (Ca) to 30 ng.g{sup -1} (Rb), respectively. (author)

  1. Determination of uranium and thorium by X-ray fluorescence analysis in ores and derivatives

    Sato, I.M.

    1979-01-01

    A method to determinate the elements thorium and uranium by X-rays fluorescence in ores and derivatives is presented. The chosen samples are ores from Morro do Agostinho, Pocos de Caldas, Minas Gerais and monazite concentrated from Nucleomon which has the feature of being complex, and which is a type of material frequently found in nuclear technology. The method of fusion is chosen to prepare the samples, in which they are fused in borax in its natural form thus, proposing analyses of those elements without any previous chemical treatment. In the analyses of uranium, the effect of absorption of iron existing in the distinctive line ULα (n=2) of second order is mathematically corrected, instead of baing eliminated by chemical separation. The determination of thorium is made through the method of double-dilution in which several reasons have shown the advantages of its employment. The precision in function the coefficient of variation in percentage and the accuracy of the method proposed are discussed [pt

  2. Determination of some main elements and traces by x-ray fluorescence analysis in silicate rocks: a comparative study of two analytical techniques

    Andrade, M.D. de.

    1977-01-01

    The determinations of silicon, magnesium, iron, potassium, calcium, titanium, manganese, barium, strontium, rubidium, zirconium and scandium in felsic and mafic rocks, by X ray fluorescence analysis are presented. (author)

  3. Fundamental quantification procedure for total reflection X-ray fluorescence spectra analysis and elements determination

    Wegrzynek, D.; Holynska, B.

    1997-01-01

    A method for the determination of the concentrations of elements in particulate-like samples measured in total reflection geometry is proposed. In the proposed method the fundamental parameters are utilized for calculating the sensitivities of elements and an internal standard is used to account for the unknown mass per unit area of a sample and geometrical constant of the spectrometer. The modification of the primary excitation spectrum on its way to a sample has been taken into consideration. The concentrations of the elements to be determined are calculated simultaneously with the spectra deconvolution procedure. In the process of quantitative analysis the intensities of all X-ray peaks corresponding to K and L-series lines present in the analyzed spectrum are taken into account. (Author)

  4. Determination of rare earth oxides in Li{sub 2}CO{sub 3} by x-ray fluorescence analysis

    Mengfu, Wei; Xinmian, Xu [Sichuan Inst. of Material and Technology (China)

    1994-07-01

    The mechanism of light elements incoherent scatter has been studied. By combining the incoherent scatter intensity with character line intensity to calculate the appearance concentration, the Lucas-Tooth and Pyne intensity correction model is corrected. By using this model and least-square method of regression of linear equations, the x-ray fluorescence analysis method is used for determining Sc{sub 2}O{sub 3}, Y{sub 2}O{sub 3}, La{sub 2}O{sub 3}, Tm{sub 2}O{sub 3} and Lu{sub 2}O{sub 3} in Li{sub 2}CO{sub 3} which are standard samples in the laboratory. The precision of the method is better than 4.0%, and the best is up to 1.4%. Advantages of the method are accurate, easy to control, fast and various elements can be simultaneously determined.

  5. Determination of total iron in iron ore by x-ray fluorescence analysis using the Compton effect: comparison with others analytical techniques

    Castilho, M.V. de; Oliveira, R.C.

    1991-01-01

    Total iron in iron ores is determines by X-ray fluorescence analysis method using the compton effect. The Bragg angle is determined for compton no-coherent scattering related to K alpha of Rhodium. This measurement procedure can be used for best fitting of analytical results in X-ray fluorescence, when compared with others methods used for results corrections. (M.V.M.)

  6. Determination of sulfur and chlorine in fodder by X-ray fluorescence spectral analysis and comparison with other analytical methods

    Nečemer, Marijan; Kump, Peter; Rajčevič, Marija; Jačimović, Radojko; Budič, Bojan; Ponikvar, Maja

    2003-07-01

    Sulfur and chlorine are essential elements in the metabolic processes of ruminants, and correct planning strategy of ruminant nutrition should provide a sufficient content of S and Cl in the animal's body. S and Cl can be found in various types of animal fodder in the form of organic compounds and minerals. In this work, the Cl and S content in forage was determined by X-ray fluorescence spectrometry (XRF), and its performance was then compared in parallel analyses by instrumental neutron activation analysis (INAA), inductively coupled plasma atomic emission spectrometry (ICP-AES) and potentiometric methods. The results were compared and critically evaluated in order to assess the performance and capability of the XRF technique in analysis of animal fodder.

  7. Determination of sulfur and chlorine in fodder by X-ray fluorescence spectral analysis and comparison with other analytical methods

    Necemer, Marijan; Kump, Peter; Rajcevic, Marija; Jacimovic, Radojko; Budic, Bojan; Ponikvar, Maja

    2003-07-18

    Sulfur and chlorine are essential elements in the metabolic processes of ruminants, and correct planning strategy of ruminant nutrition should provide a sufficient content of S and Cl in the animal's body. S and Cl can be found in various types of animal fodder in the form of organic compounds and minerals. In this work, the Cl and S content in forage was determined by X-ray fluorescence spectrometry (XRF), and its performance was then compared in parallel analyses by instrumental neutron activation analysis (INAA), inductively coupled plasma atomic emission spectrometry (ICP-AES) and potentiometric methods. The results were compared and critically evaluated in order to assess the performance and capability of the XRF technique in analysis of animal fodder.

  8. Fluorescence correlation spectroscopy analysis for accurate determination of proportion of doubly labeled DNA in fluorescent DNA pool for quantitative biochemical assays.

    Hou, Sen; Sun, Lili; Wieczorek, Stefan A; Kalwarczyk, Tomasz; Kaminski, Tomasz S; Holyst, Robert

    2014-01-15

    Fluorescent double-stranded DNA (dsDNA) molecules labeled at both ends are commonly produced by annealing of complementary single-stranded DNA (ssDNA) molecules, labeled with fluorescent dyes at the same (3' or 5') end. Because the labeling efficiency of ssDNA is smaller than 100%, the resulting dsDNA have two, one or are without a dye. Existing methods are insufficient to measure the percentage of the doubly-labeled dsDNA component in the fluorescent DNA sample and it is even difficult to distinguish the doubly-labeled DNA component from the singly-labeled component. Accurate measurement of the percentage of such doubly labeled dsDNA component is a critical prerequisite for quantitative biochemical measurements, which has puzzled scientists for decades. We established a fluorescence correlation spectroscopy (FCS) system to measure the percentage of doubly labeled dsDNA (PDL) in the total fluorescent dsDNA pool. The method is based on comparative analysis of the given sample and a reference dsDNA sample prepared by adding certain amount of unlabeled ssDNA into the original ssDNA solution. From FCS autocorrelation functions, we obtain the number of fluorescent dsDNA molecules in the focal volume of the confocal microscope and PDL. We also calculate the labeling efficiency of ssDNA. The method requires minimal amount of material. The samples have the concentration of DNA in the nano-molar/L range and the volume of tens of microliters. We verify our method by using restriction enzyme Hind III to cleave the fluorescent dsDNA. The kinetics of the reaction depends strongly on PDL, a critical parameter for quantitative biochemical measurements. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. Radionuclide X-ray fluorescence analysis

    Cechak, T.

    1994-01-01

    The author's achievements in the title field are summarized and discussed. The following topics are dealt with: (i) principles of radionuclide X-ray fluorescence analysis; (ii) mathematical methods in X-ray fluorescence analysis; (iii) Ross differential filters; (iv) application of radionuclide X-ray fluorescence analysis in the coal industry (with emphasis on the determination of the ash content, sulfur content, and arsenic content of coal); and (v) evaluation of the X-ray fluorescence analyzer from the radiological safety point of view. (P.A.)

  10. Silver content determination in mining and ore dressing using radionuclide-excited X-ray fluorescence analysis

    Koerner, B.; George, R.; Ratnikow, W.

    1989-01-01

    A laborsaving method based on radionuclide-excited X-ray fluorescence is described for the determination of silver in mining and ore dressing. Detection limits reached under operation conditions and measuring errors are discussed and compared with results from chemical analyses

  11. Optimal Fluorescence Waveband Determination for Detecting Defective Cherry Tomatoes Using a Fluorescence Excitation-Emission Matrix

    In-Suck Baek

    2014-11-01

    Full Text Available A multi-spectral fluorescence imaging technique was used to detect defective cherry tomatoes. The fluorescence excitation and emission matrix was used to measure for defects, sound surface and stem areas to determine the optimal fluorescence excitation and emission wavelengths for discrimination. Two-way ANOVA revealed the optimal excitation wavelength for detecting defect areas was 410 nm. Principal component analysis (PCA was applied to the fluorescence emission spectra of all regions at 410 nm excitation to determine the emission wavelengths for defect detection. The major emission wavelengths were 688 nm and 506 nm for the detection. Fluorescence images combined with the determined emission wavebands demonstrated the feasibility of detecting defective cherry tomatoes with >98% accuracy. Multi-spectral fluorescence imaging has potential utility in non-destructive quality sorting of cherry tomatoes.

  12. Trace metal determinations by total-reflection x-ray fluorescence analysis in the open Atlantic Ocean

    Schmidt, D.; Gerwinski, W.; Radke, I.

    1993-01-01

    The Intergovernmental Oceanographic Commission (IOC), as a major component of its programme ''Global Investigation of Pollution in the Marine Environment'' (GIPME), maintains a long-standing project on ''Open Ocean Baseline Studies of Trace Contaminants''. Initially, the Atlantic Ocean and trace metals were selected. Four deep-water stations in the Cape Basin, Angola Basin, Cape Verde Abyssal Plain and Seine Abyssal Plain were regularly sampled for at least 36 depths. Additional samples were taken between stations. Samples were distributed to participants and a similar number of additional laboratories. As a central part of our own contribution to the project, we determined the trace heavy metals manganese, nickel, copper, zinc and lead and the lighter selenium by total-reflection X-ray fluorescence analysis. For the TXRF, the pre-enrichment of the trace metals and the separation from the salt matrix were performed by complexation with sodium dibenzyldithiocarbamate and reverse-phase chromatography. Generally, very low levels of trace elements were found in filtered and unfiltered water samples from these remote areas of the open Atlantic Ocean. Typical examples of the distributions of trace metal concentrations on depth profiles from the four deep-water stations as well as intercomparisons between the stations are presented. (author)

  13. Determination of Mn, Fe, Ni, Cu, Zn and Pb contents in samples in samples of apple trees by radionuclide X-ray fluorescence analysis

    Bumbalova, A.; Havranek, E.; Harangozo, M.

    1982-01-01

    The applicability of the radionuclide X-ray fluorescence analysis (RXFA) for qualitative and quantitative evaluation of environmental plant samples is discussed and examples of determination of Mn, Fe, Ni, Cu, Zn, Pb in samples of apple trees are given. The instrumentation, the standard and sample preparation are also presented. (author)

  14. Determination of gold accumulation in human tissues caused by gold therapy using x-ray fluorescence analysis

    Bacso, J.; Uzonyi, I.; Dezsoe, B.

    1986-08-01

    Human autopsy tissues from five patients with rheumatoid arthritis treated earlier with aqueous solution of gold and those from untreated control with the same disease were analyzed by x-ray fluorescence spectrometry using a conventional Si(Li) detection system. The gold and zinc concentrations of tissues were determined and compared with literature data. Correlation was found between Zn and Au concentrations in heart, lung, kidney and liver tissues. (author)

  15. Determination of elements in bone of tuberculous-arthritis patients by radioisotope X-ray fluorescence analysis

    Akyuez, T.; Bassari, A.; Akyuez, S.

    1998-01-01

    The quantitative analysis of the human femoral bone of 17 tuberculosis-arthritis (Koch-arthritis) patients (9 males and 8 females) in the age range of 45-65, for Ca, P, Zn, Sr, Ba, La and Ce were performed by using radioisotope energy dispersive X-ray fluorescence (EDXRF) and the results were compared with those of 12 healthy control groups (8 males and 4 females) in the range of 37-58. The results indicate that the concentrations of P, Ca and Sr in the control group are higher than those in the patient group, while the concentrations of Zn, Ba, La and Ce are not significantly different. (author)

  16. Comparative analysis of dose rates in bricks determined by neutron activation analysis, alpha counting and X-ray fluorescence analysis for the thermoluminescence fine grain dating method

    Bártová, H.; Kučera, J.; Musílek, L.; Trojek, T.

    2014-11-01

    In order to evaluate the age from the equivalent dose and to obtain an optimized and efficient procedure for thermoluminescence (TL) dating, it is necessary to obtain the values of both the internal and the external dose rates from dated samples and from their environment. The measurements described and compared in this paper refer to bricks from historic buildings and a fine-grain dating method. The external doses are therefore negligible, if the samples are taken from a sufficient depth in the wall. However, both the alpha dose rate and the beta and gamma dose rates must be taken into account in the internal dose. The internal dose rate to fine-grain samples is caused by the concentrations of natural radionuclides 238U, 235U, 232Th and members of their decay chains, and by 40K concentrations. Various methods can be used for determining trace concentrations of these natural radionuclides and their contributions to the dose rate. The dose rate fraction from 238U and 232Th can be calculated, e.g., from the alpha count rate, or from the concentrations of 238U and 232Th, measured by neutron activation analysis (NAA). The dose rate fraction from 40K can be calculated from the concentration of potassium measured, e.g., by X-ray fluorescence analysis (XRF) or by NAA. Alpha counting and XRF are relatively simple and are accessible for an ordinary laboratory. NAA can be considered as a more accurate method, but it is more demanding regarding time and costs, since it needs a nuclear reactor as a neutron source. A comparison of these methods allows us to decide whether the time- and cost-saving simpler techniques introduce uncertainty that is still acceptable.

  17. Comparative analysis of dose rates in bricks determined by neutron activation analysis, alpha counting and X-ray fluorescence analysis for the thermoluminescence fine grain dating method

    Bártová, H.; Kučera, Jan; Musílek, L.; Trojek, T.

    2014-01-01

    Roč. 104, NOV (2014), s. 393-397 ISSN 0969-806X. [1st International Conference on Dosimetry and its Applications (ICDA). Prague, 23.6.2013-28.6.2013] R&D Projects: GA MŠk(XE) LM2011019 Institutional support: RVO:61389005 Keywords : Alpha coutning * neutron activation analysis * X-ray fluorescence * thermoluminescence dating * dose rate Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 1.380, year: 2014

  18. Two-color fluorescence analysis of individual virions determines the distribution of the copy number of proteins in herpes simplex virus particles.

    Clarke, Richard W; Monnier, Nilah; Li, Haitao; Zhou, Dejian; Browne, Helena; Klenerman, David

    2007-08-15

    We present a single virion method to determine absolute distributions of copy number in the protein composition of viruses and apply it to herpes simplex virus type 1. Using two-color coincidence fluorescence spectroscopy, we determine the virion-to-virion variability in copy numbers of fluorescently labeled tegument and envelope proteins relative to a capsid protein by analyzing fluorescence intensity ratios for ensembles of individual dual-labeled virions and fitting the resulting histogram of ratios. Using EYFP-tagged capsid protein VP26 as a reference for fluorescence intensity, we are able to calculate the mean and also, for the first time to our knowledge, the variation in numbers of gD, VP16, and VP22 tegument. The measurement of the number of glycoprotein D molecules was in good agreement with independent measurements of average numbers of these glycoproteins in bulk virus preparations, validating the method. The accuracy, straightforward data processing, and high throughput of this technique make it widely applicable to the analysis of the molecular composition of large complexes in general, and it is particularly suited to providing insights into virus structure, assembly, and infectivity.

  19. Fluorescent determination of neptunium in plutonium

    Alexandruk, V.M.; Babaev, A.S.; Dem'yanova, T.A.; Stepanov, A.V.

    1991-01-01

    This paper describes a new procedure for direct determination of Neptunium in Plutonium using laser induced time resolved fluorescence method. The procedure based on measurement of fluorescence intensity of Neptunium followed its concentration in effective layer of pellet of calcium fluoride. Detection limit of determination of Neptunium is 2 10 -12 g. At the level of Neptunium content in Plutonium more than 5 ppm relative standard deviation is equal 0.08-0.12. For carrying out of single measurement it is necessary neither more nor less 5 mkg Plutonium

  20. Limestone rocks analysis by X-ray fluorescence analysis

    Izquierdo M, G.; Ponce R, R.; Vazquez J, J.

    1996-01-01

    By request of a private company, employing basically X-ray fluorescence analysis (X RF), was established a fast and accurate method for the analysis of the major elements in limestone rocks. Additionally, for complementing analysis was determined by ion chromatography, the chlorides appearance and by atomic absorption of sodium. By gravimetry, was determined the losses by ignition and the alpha quartz. (Author)

  1. Determination of Cr2O3 in chrome-tanned leather by radionuclide-excited X-ray fluorescence analysis

    Melich, M.; Palagyi, S.; Kern, M.

    1989-01-01

    Preliminary results on the determination of Cr 2 O 3 in chrome-tanned leather by measuring the content of Cr by means of radionuclide-excited XRF analysis are reported. For excitation a 3.7 GBq 238 Pu source was used and the characteristic K X-rays of Cr were detected with a planar Si(Li) detector. Both smooth and rough sides of the leather were analyzed directly or with a pair of V/Ti balanced filters. A fairly good correlation was found between Cr Kx counts of the rough side and the Cr 2 O 3 concentrations determined chemically in the range of 3.5 to 6.0% Cr 2 O 3 . The method renders possible a rapid and non-destructive determination of Cr 2 O 3 in various leather samples. (author)

  2. Multielemental analysis of osseous remains by x-ray fluorescence to determine types of diets from the Cultura Lima (II B.C. - VIII A.C)

    Montalvo B, A.

    1997-01-01

    The multielemental analysis of 29 human bone samples and sediments from the Lima Culture (III c. BC to IX c. AC) were analyzed by x-ray fluorescence technique with Cd-109 excitation source Si(Li) detector, Canberra associated electronic and PCA-II nucleus multichannel card, in order to determine to determine the diet type of these antique inhabitant. The elements found in bone rests were Ca, Sr, Zn, Mn, Fe, Ni, Cu, Rb, Zn and Pb, and As in one of the clavicles. In sediment samples we obtained a major quantity of elements. According to the Sr an Zn obtained values in osseous rest and the developed regression model, we can conclude that the ancient inhabitants of Lima Culture had an omnivorous feeding with a carnivore tendency due to its geographic location. (author). 35 refs., 9 figs., 10 tabs., 6 ills

  3. Anodic electrode position of cyanometallates as sample preparation for the determination of transition metals from water samples using X-ray fluorescence analysis

    Wundt, K.; Duschner, H.; Starke, K.

    1978-01-01

    The anodic separation of cyanometallates of propanol -2/Water mixtures at high electrical field strengths was developed as new technique for sample preparation. The optimization of the parameters of the system (high voltage applied, current density, separation time and composition of the solution) resulted in quantitative precipitation of the metallates of Fe, Co, Ni, Cu, Zn, Cd and Ag in homogeneous, thin and strong-adhering layer with mass densities of between 1 nmol cm -2 and 1 μmol cm -2 on high-purity aluminium foils. Metals not forming anionic complexes remain in solution with simualtaneous quantitative multielement separation. The described technique is part of a method to determine heavy metal traces in water samples. It comprises the nonspecific sorption on cation exchangers, the elution of the transition metals as cyanometallates, their electrode position on aluminium foil and the determination by X-ray fluorescence analysis. Model experiments illustrate the possible applications of the method. (orig.) [de

  4. Fluorescence-labeled methylation-sensitive amplified fragment length polymorphism (FL-MS-AFLP) analysis for quantitative determination of DNA methylation and demethylation status.

    Kageyama, Shinji; Shinmura, Kazuya; Yamamoto, Hiroko; Goto, Masanori; Suzuki, Koichi; Tanioka, Fumihiko; Tsuneyoshi, Toshihiro; Sugimura, Haruhiko

    2008-04-01

    The PCR-based DNA fingerprinting method called the methylation-sensitive amplified fragment length polymorphism (MS-AFLP) analysis is used for genome-wide scanning of methylation status. In this study, we developed a method of fluorescence-labeled MS-AFLP (FL-MS-AFLP) analysis by applying a fluorescence-labeled primer and fluorescence-detecting electrophoresis apparatus to the existing method of MS-AFLP analysis. The FL-MS-AFLP analysis enables quantitative evaluation of more than 350 random CpG loci per run. It was shown to allow evaluation of the differences in methylation level of blood DNA of gastric cancer patients and evaluation of hypermethylation and hypomethylation in DNA from gastric cancer tissue in comparison with adjacent non-cancerous tissue.

  5. Determination of U, Th and K in bricks by gamma-ray spectrometry, X-ray fluorescence analysis and neutron activation analysis

    Bártová, H.; Kučera, J.; Musílek, L.; Trojek, T.; Gregorová, E.

    2017-11-01

    Knowledge of the content of natural radionuclides in bricks can be important in some cases in dosimetry and application of ionizing radiation. Dosimetry of naturally occurring radionuclides in matter (NORM) in general is one of them, the other one, related to radiation protection, is radon exposure evaluation, and finally, it is needed for the thermoluminescence (TL) dating method. The internal dose rate inside bricks is caused mostly by contributions of the natural radionuclides 238U, 232Th, radionuclides of their decay chains, and 40K. The decay chain of 235U is usually much less important. The concentrations of 238U, 232Th and 40K were measured by various methods, namely by gamma-ray spectrometry, X-ray fluorescence analysis (XRF), and neutron activation analysis (NAA) which was used as a reference method. These methods were compared from the point of view of accuracy, limit of detection (LOD), amount of sample needed and sample handling, time demands, and instrument availability.

  6. Heavy element concentration determination by the x-ray fluorescence analysis using radioisotope {gamma}-ray sources; Dosage d'elements lourds par fluorescence X utilisant des radio-sources de rayons gamma

    Enomoto, S [Commissariat a l' Energie Atomique, Dir. des Materiaux et des Combustibles Nucleaires, Saclay (France). Centre d' Etudes Nucleaires

    1968-07-01

    A theoretical and experimental study has been made on the fluorescence analysis of high atomic number element, using {gamma}-ray sources for excitation and characteristic K X-rays for the measurement. The choice of the proper {gamma}-ray energy according to the conditions of the determination is considered. The author has studied the usefulness of using the backscattered {gamma}-rays as a correction mean for matrix and grain-size effects. Sources of {sup 153}Gd, {sup 57}Co, {sup 137}Cs have been used for excitation using collimated geometries. Concentration measurements of tungsten in steel, tungsten and lead in aqueous solution, PbS in SiO{sub 2}-PbS powder mixtures have been done, as well as thickness evaluation of gold layers on copper. A precision of about 0.2 per cent (abs.) is obtained for lead determination in light matrixes. A probe design is proposed for the continuous determination of lead in aqueous solutions. (author) [French] On etudie de maniere theorique et experimentale l'analyse d'elements a nombre atomique eleve par fluorescence en utilisant des sources de rayons {gamma} pour l'excitation, et des rayons-X K caracteristiques pour la mesure. On considere le choix de l'energie appropriee des rayons {gamma} suivant les conditions experimentales. L'utilite d'employer les rayons {gamma} retrodiffuses pour corriger les effets de la matrice et de la dimension des grains est etudiee. Des sources de {sup 153}Gd, de {sup 57}Co et de {sup 137}Cs a geometrie collimatee ont ete utilisees pour l'excitation. Des mesures de la concentration du tungstene dans l'acier, du tungstene et du plomb en solutions aqueuses, et du PbS dans des melanges de poudre SiO{sub 2}-PbS ont ete entreprises ainsi que l'evaluation de l'epaisseur des couches d'or sur le cuivre. On obtient une precision d'environ 0,2 pour cent (en absolu) pour la determination du plomb dans des matrices legeres. On propose un modele de sonde pour la determination en continu du plomb en solution aqueuse

  7. Simultaneous determination of estrogens (ethinylestradiol and norgestimate) concentrations in human and bovine serum albumin by use of fluorescence spectroscopy and multivariate regression analysis.

    Hordge, LaQuana N; McDaniel, Kiara L; Jones, Derick D; Fakayode, Sayo O

    2016-05-15

    The endocrine disruption property of estrogens necessitates the immediate need for effective monitoring and development of analytical protocols for their analyses in biological and human specimens. This study explores the first combined utility of a steady-state fluorescence spectroscopy and multivariate partial-least-square (PLS) regression analysis for the simultaneous determination of two estrogens (17α-ethinylestradiol (EE) and norgestimate (NOR)) concentrations in bovine serum albumin (BSA) and human serum albumin (HSA) samples. The influence of EE and NOR concentrations and temperature on the emission spectra of EE-HSA EE-BSA, NOR-HSA, and NOR-BSA complexes was also investigated. The binding of EE with HSA and BSA resulted in increase in emission characteristics of HSA and BSA and a significant blue spectra shift. In contrast, the interaction of NOR with HSA and BSA quenched the emission characteristics of HSA and BSA. The observed emission spectral shifts preclude the effective use of traditional univariate regression analysis of fluorescent data for the determination of EE and NOR concentrations in HSA and BSA samples. Multivariate partial-least-squares (PLS) regression analysis was utilized to correlate the changes in emission spectra with EE and NOR concentrations in HSA and BSA samples. The figures-of-merit of the developed PLS regression models were excellent, with limits of detection as low as 1.6×10(-8) M for EE and 2.4×10(-7) M for NOR and good linearity (R(2)>0.994985). The PLS models correctly predicted EE and NOR concentrations in independent validation HSA and BSA samples with a root-mean-square-percent-relative-error (RMS%RE) of less than 6.0% at physiological condition. On the contrary, the use of univariate regression resulted in poor predictions of EE and NOR in HSA and BSA samples, with RMS%RE larger than 40% at physiological conditions. High accuracy, low sensitivity, simplicity, low-cost with no prior analyte extraction or separation

  8. Design and construction of a detection system for the determination of lead in blood using x-ray fluorescence analysis. Progress report, August 1, 1974--July 31, 1975

    Laurer, G.R.; Kneip, T.J.

    1975-01-01

    Intercomparison difficulties between x-ray fluorescence (XRF) and atomic absorption (AA) measurements of blood lead were due to weight variations in the samples which are correlated to the hemoglobin content. Correction factors were developed to account for changes in background and sensitivity due to weight and hence hemoglobin content variations. Good agreement was achieved in comparisons of XRF and AA determinations on baboon blood, and a preliminary intercomparison with the New York City Health Department demonstrated that the corrected XRF values are accurate for children's blood. The XRF system can accurately determine blood lead concentrations in the range of 0.1 to 3.0 ppM. The difference in the content of zinc in the urine of two individuals undergoing chelation therapy was determined, using XRF analysis, on samples taken before and after treatment. The ratio of the count rate under the Zn K/sub alpha/ peak for one of these persons after treatment was 250 : 1, compared to before chelation. (U.S.)

  9. Method for determination of Fe, Co, Ni, Cu, Zn and Pb in sea water using X-ray fluorescence analysis, after concentration step of these elements by coprecipitation with APDC

    Lam, P.; Estevez Alvarez, J.R.; Pupo Gonzalez, I.; Ramirez, M.; Rivera, N.

    1998-01-01

    In this work an analytical procedure has been applied to the to the determination of Fe, Co, Ni, Cu, Zn y Pb in seawater, that includes a coprecipitation step applied of these metals with APDC. The final analysis is carried out by X-Ray Fluorescence Analysis thin layer absolute method

  10. Study of granitic biotites by X-ray fluorescence analysis: determination of iron, manganese, titanium, calcium, potassium, silicon and aluminium

    Toubes, R. O.; Bermudez Polonio, J.

    1968-01-01

    A method for the quantitative determination of iron, manganese, titanium, calcium potassium, silicon, and aluminium, is reported, Sample preparation is carried out by the miniature flux technique, and rubidium is used as internal standard for silicon and aluminium. (Author) 5 refs

  11. Rapid qualitative determination of main components in archeological samples by radioisotope-excited X-ray fluorescence analysis

    Shenberg, C.; Boazi, M.

    1975-01-01

    Archeological specimen were examined by the radioisotope-excited X-ray method to determine their chemical composition. Individual K and L X-rays of Fe, Ni, Cu, Zn, Pb, Mo, Ag, In, Sn and Ba were induced by using 241 Am - I and 241 Am- Tm source- target assemblies. A lithium drifted silicone diode coupled to a 400-channel analyzer was used for detection. No sample preparation was required and all the elements were measured simultaneously in 40 min counting time. The use of different targets coupled with only one primary source makes this technique simple, versatile and economical. The target materials are suitable for exciting K and L X-rayd from potassium to uranium. In addition, the targets, as monoenergetic secondary sources, minimize the background effect. (T.G.)

  12. Determination of antioxidant content in biodiesel by fluorescence spectroscopy

    Magalhaes, Keurison F.; Caires, Anderson R.L. [Universidade Federal da Grande Dourados, MS (Brazil). Grupo de Optica Aplicada; Oliveira, Samuel L. [Universidade Federal de Mato Grosso do Sul (UFMS), MS (Brazil). Grupo de Optica e Fotonica

    2011-07-01

    Full text. Biodiesel is an alternative fuel composed by mono-alkyl esters obtained from vegetable oils or animal fats. Due to its chemical structure, biodiesel is highly susceptible to oxidation which leads to formation of insoluble gums and sediments that can block the filter system of fuel injection. Biodiesel made from vegetable oils typically has a small amount of natural antioxidants so that it is necessary to add synthetic antioxidants to enhance its stability and retain their properties for a longer period. The main antioxidants are synthetic phenolic compounds such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and tert-butyl hydroquinone (TBHQ) as well as natural antioxidants as tocopherols. The fluorescence spectroscopy has been applied for determination of phenolic compounds in oils. Here, a method based on fluorescence is proposed to quantify the BHA and TBHQ antioxidant concentration in biodiesel produced from sunflower and soybean oils. Soybean and sunflower biodiesel were obtained by transesterification of fatty alcohol in the presence of NaOH as catalyst. The reactions were carried out in the molar ratio of 6:1 methanol/oil. After the production and purification, biodiesel samples were stored. Biodiesel samples with BHA and TBHQ concentrations from 1000 to 8000 ppm (m/m) were pre- pared. These samples were diluted in ethanol (95%) in order to measure the fluorescence spectra. Fluorescence and excitation spectra of the solutions were recorded at room temperature using a spectrofluorimeter. The emission spectra were obtained under excitation at about 310nm and fluorescence in the 320-800nm range was evaluated. Biodiesel samples without BHA and TBHQ showed fluorescence band at about 420nm, which can be attributed to tocopherols inherent to the vegetable oils used in the biodiesel production. The addition of BHA and/or TBHQ is responsible for the appearance of a fluorescence band around 330nm. It was verified that the fluorescence

  13. Capacity of X-ray fluorescence analysis

    Wobrauschek, P.; Kregsamer, P.

    1997-01-01

    X-Ray fluorescence analysis (XRF) is a powerful analytical tool for the qualitative and quantitative determination of chemical elements in a sample. Two different detection principles are accepted widely: wavelength dispersive and energy dispersive. Various sources for XRF are discussed: X-ray tubes, accelerators for particle induced XRF, radioactive isotopes, and the use of synchrotron radiation. Applications include environmental, technical, medical, fine art, and forensic studies. Due to the demands of research and application special techniques like total reflection XRF (TXRF) were developed with ultimately achievable detection limits in the femtogram region. The elements detectable by XRF range from Be to U. (author)

  14. Fast and accurate automated cell boundary determination for fluorescence microscopy

    Arce, Stephen Hugo; Wu, Pei-Hsun; Tseng, Yiider

    2013-07-01

    Detailed measurement of cell phenotype information from digital fluorescence images has the potential to greatly advance biomedicine in various disciplines such as patient diagnostics or drug screening. Yet, the complexity of cell conformations presents a major barrier preventing effective determination of cell boundaries, and introduces measurement error that propagates throughout subsequent assessment of cellular parameters and statistical analysis. State-of-the-art image segmentation techniques that require user-interaction, prolonged computation time and specialized training cannot adequately provide the support for high content platforms, which often sacrifice resolution to foster the speedy collection of massive amounts of cellular data. This work introduces a strategy that allows us to rapidly obtain accurate cell boundaries from digital fluorescent images in an automated format. Hence, this new method has broad applicability to promote biotechnology.

  15. Possibilities of radioisotopic fluorescence analysis application in copper industry

    Parus, J.; Kierzek, J.

    1983-01-01

    The main applications of X-ray fluorescence analysis in copper industry such as: copper ores and other materials from flotation analysis, lead and silver determination in blister copper, analysis of metallurgic dusts and copper base alloys analysis are presented. (A.S.)

  16. Blood selenium content determination by X-ray fluorescence

    Mainardi, R.T.

    1987-01-01

    The presence of some elements in small amounts (traces) in the human body is of foremost importance for the prevention and treatment of several diseases. It has been recently shown that traces of selenium in blood are closely related to the occurrence of miotonic distrophy, a muscular disease that is affecting a significant percentage of the population. This work describes a simple procedure to determine selenium in human blood serum by energy dispersive X-ray fluorescence analysis. Final quantification is achieved through the addition of titanium as an internal standard. (Author) [es

  17. Pulp tissue in sex determination: A fluorescent microscopic study

    Nayar, Amit; Singh, Harkanwal Preet; Leekha, Swati

    2014-01-01

    Aims: To determine and compare the reliability of pulp tissue in determination of sex and to analyze whether caries have any effect on fluorescent body test. Materials and Methods: This study was carried on 50 maxillary and mandibular teeth (25 male teeth and 25 female teeth), which were indicated for extraction. The teeth are categorized into 5 groups, 10 each (5 from males and 5 from females) on the basis of caries progression. The pulp cells are stained with quinacrine hydrochloride and observed with fluorescent microscope for fluorescent body. Gender is determined by identification of Y chromosome fluorescence in dental pulp. Results: Fluorescent bodies were found to be more in sound teeth in males as the caries increase the mean percentage of fluorescent bodies observed decreases in males. We also observed the fluorescent spots in females, and the value of the spot increases in female as the caries progresses, thereby giving false positive results in females. Conclusion: Sex determination by fluorescent staining of the Y chromosome is a reliable technique in teeth with healthy pulps or caries with enamel or up to half way of dentin. Teeth with caries involving pulp cannot be used for sex determination. PMID:25125912

  18. [The intraoperative determination of intestinal vitality with a fluorescent indicator].

    Ivanov, A; Terziev, I

    1997-01-01

    Intestinal obstruction due to strangulation is induced in dogs under experimental conditions, with intestinal wall vitality assessment done on the ground of standard clinical criteria, using fluorescence dye and UV rays, as well as histological study. Sensitivity, specificity and prognostic value of each of the methods employed are determined. The fluorescence method advantages are recorded, and the prospects of its clinical implementation are estimated.

  19. Scanning fluorescent microscopy is an alternative for quantitative fluorescent cell analysis.

    Varga, Viktor Sebestyén; Bocsi, József; Sipos, Ferenc; Csendes, Gábor; Tulassay, Zsolt; Molnár, Béla

    2004-07-01

    Fluorescent measurements on cells are performed today with FCM and laser scanning cytometry. The scientific community dealing with quantitative cell analysis would benefit from the development of a new digital multichannel and virtual microscopy based scanning fluorescent microscopy technology and from its evaluation on routine standardized fluorescent beads and clinical specimens. We applied a commercial motorized fluorescent microscope system. The scanning was done at 20 x (0.5 NA) magnification, on three channels (Rhodamine, FITC, Hoechst). The SFM (scanning fluorescent microscopy) software included the following features: scanning area, exposure time, and channel definition, autofocused scanning, densitometric and morphometric cellular feature determination, gating on scatterplots and frequency histograms, and preparation of galleries of the gated cells. For the calibration and standardization Immuno-Brite beads were used. With application of shading compensation, the CV of fluorescence of the beads decreased from 24.3% to 3.9%. Standard JPEG image compression until 1:150 resulted in no significant change. The change of focus influenced the CV significantly only after +/-5 microm error. SFM is a valuable method for the evaluation of fluorescently labeled cells. Copyright 2004 Wiley-Liss, Inc.

  20. Mercury mass measurement in fluorescent lamps via neutron activation analysis

    Viererbl, L.; Vinš, M.; Lahodová, Z.; Fuksa, A.; Kučera, J.; Koleška, M.; Voljanskij, A.

    2015-01-01

    Mercury is an essential component of fluorescent lamps. Not all fluorescent lamps are recycled, resulting in contamination of the environment with toxic mercury, making measurement of the mercury mass used in fluorescent lamps important. Mercury mass measurement of lamps via instrumental neutron activation analysis (NAA) was tested under various conditions in the LVR-15 research reactor. Fluorescent lamps were irradiated in different positions in vertical irradiation channels and a horizontal channel in neutron fields with total fluence rates from 3×10 8 cm −2 s −1 to 10 14 cm −2 s −1 . The 202 Hg(n,γ) 203 Hg nuclear reaction was used for mercury mass evaluation. Activities of 203 Hg and others induced radionuclides were measured via gamma spectrometry with an HPGe detector at various times after irradiation. Standards containing an Hg 2 Cl 2 compound were used to determine mercury mass. Problems arise from the presence of elements with a large effective cross section in luminescent material (europium, antimony and gadolinium) and glass (boron). The paper describes optimization of the NAA procedure in the LVR-15 research reactor with particular attention to influence of neutron self-absorption in fluorescent lamps. - Highlights: • Mercury is an essential component of fluorescent lamps. • Fluorescent lamps were irradiated in neutron fields in research reactor. • 203 Hg induced radionuclide activity was measured using gamma spectrometry. • Mercury mass in fluorescent lamps can be measured by neutron activation analysis.

  1. Determination of uranium in seawater by fluorescence spectrometry

    Kawashima, Toshi; Kawakubo, Senkichi; Minegishi, Hisako.

    1984-01-01

    A Fluorescence spectrometry for the determination of uranium in seawater has been developed. Anion exchange separation of uranium from seawater followed by preparation of NaF-carbonate cake and by spectrometry for ultraviolet ray excited fluorescence of uranium on the fluoride host provide the trace determinaton of uranium at the subnano gram level. Anion exchange behavior, excitation-emission behavior of the uranium on the host and effects of foreign ions to the fluorescence have been presented. Appling the method to 1 ml of seawater 3 ppb of uranium has been determined. (author)

  2. Rapid determination of trace phosphorus, sulfur, chlorine, bromine and iodine by energy dispersive X-ray fluorescence analysis with monochromatic excitations

    Wakisaka, Tatsushi; Morita, Naoki; Hirabayashi, Tadashi; Nakahara, Taketoshi

    1998-01-01

    A useful and rapid procedure is described for the determination of trace phosphorus, sulfur, chlorine, bromine, and iodine by means of an energy dispersive X-ray fluorescence spectrometer (EDXRF) with monochromatic excitations. Using monochromatic excitations, the detection limits for phosphorus, sulfur, chlorine (Cr-Kα, 5.41 keV), bromine (Mo-Kα, 17.44 keV), and iodine (W-continuum, 40 keV) were found to be 4.6, 1.7, 0.7, 0.09 and 0.5 μg g -1 , respectively. The relative standard deviations in five replicate measurements were 0.9-1.3%. The proposed method was applied to the direct determination of sulfur in the NIST Residual Fuel Oil, and others. The results obtained by the proposed method were in good agreement with the certified values. Bromine in a seawater sample, as well as iodine and bromine in a brine sample were determined by the proposed method. The obtained results were in good agreement with those obtained by ion chromatography. (author)

  3. Analysis of Cholesterol Trafficking with Fluorescent Probes

    Maxfield, Frederick R.; Wustner, Daniel

    2012-01-01

    Cholesterol plays an important role in determining the biophysical properties of biological membranes, and its concentration is tightly controlled by homeostatic processes. The intracellular transport of cholesterol among organelles is a key part of the homeostatic mechanism, but sterol transport...... that can bind to cholesterol to reveal its distribution in cells. We also discuss the use of intrinsically fluorescent sterols that closely mimic cholesterol, as well as some minimally modified fluorophore-labeled sterols. Methods for imaging these sterols by conventional fluorescence microscopy...... and by multiphoton microscopy are described. Some label-free methods for imaging cholesterol itself are also discussed briefly....

  4. Two different preparation techniques for trace element determination of single Daphnia specimen using total reflection x-ray fluorescence analysis (TXRF)

    Woelfl, S.; Mages, M.

    2000-01-01

    Bio accumulation gives first information about the bio-availability of elements in waters and becomes more and more important for the characterization of the water quality. The use of common analytical techniques like ICP-MS and AAS requires large quantities of biologic sample material. Single preparation for example of Daphnia, a common species for bio-test experiments, are hardly possible with these procedures. Therefore alternatively quantitative TXRF element determination of individually prepared Daphnia was developed. Two preparation techniques for single freshwater crustacean specimen from a eutrophic branch of the river Elbe in the 'Rothehorn Park', Magdeburg (Daphnia: dry weight: 10 - 50 μg individuum -1 ) had been tested: (1) Wet preparation: the single Daphnia specimen had been washed with 0.45 μm filtered lake water and put onto quartz sample carriers. After air drying, the body length were determined in order to calculate the dry weight according to previously established body lengths-dry weight relationships. (2) Dry preparation: after collection specimen were washed with 0.45 μm filtered lake water and frozen in liquid nitrogen. The individual lyophilisated dried Daphnia were weighted using an ultrafine micro-balance and put onto quartz sample carriers. After preparation, addition of some μl Gallium standard solution and air drying the individual Daphnia were digested at the quartz sample carriers with 10 μl HNO 3 on a hot plate and dried once more. Finally the element concentrations were determined using a EXTRA IIA total-reflection x-ray fluorescence spectrometer. As a result of these investigations we can conclude that both, the 'dry' and 'wet' preparation method can be used for the element determination in small single crustaceans using TXRF spectrometry. It seems that the 'dry' method yields more precise results, but the wet method is easier to handle in field when samples cannot be fixed with liquid nitrogen. (author)

  5. Application of X-ray fluorescence analysis in environmental research

    Kliment, V.; Kliman, J.; Turzo, I.

    1978-01-01

    A description is presented of the X-ray fluorescence analysis principles and of its possibilities in the study of environmental pollution impact. Experiments with X-ray fluorescence analysis using 241-Am and a Ge(Li) semiconductor detector are discussed. The reproducibility of determinations in dependence on the sample preparation and the evaluation of peak surfaces of characteristic radiation is shown. The dependence of the peak surface on the elemental contents in the sample was linear. Detection limits of the investigated elements ranged in tenths of μg for 300 s measurement. (author)

  6. Automated x-ray fluorescence analysis

    O'Connell, A.M.

    1977-01-01

    A fully automated x-ray fluorescence analytical system is described. The hardware is based on a Philips PW1220 sequential x-ray spectrometer. Software for on-line analysis of a wide range of sample types has been developed for the Hewlett-Packard 9810A programmable calculator. Routines to test the system hardware are also described. (Author)

  7. Determination of U, Th and K in bricks by gamma -ray spectrometry, X-ray fluorescence analysis and neutron activation analysis

    Bártová, H.; Kučera, Jan; Musílek, L.; Trojek, T.; Gregorová, E.

    2017-01-01

    Roč. 140, NOV (2017), s. 161-166 ISSN 0969-806X R&D Projects: GA MŠk LM2015056 Institutional support: RVO:61389005 Keywords : Gamma-ray spectrometry * neutron activation analysis * environmental dosimetry Subject RIV: CB - Analytical Chemistry , Separation OBOR OECD: Analytical chemistry Impact factor: 1.315, year: 2016

  8. Determination of technetium by total reflection x-ray fluorescence

    Bermudez, J.I.; Greaves, E.D.; Nemeth, P.

    2000-01-01

    We describe a technique using total reflection x-ray fluorescence (TXRF) for determination of Technetium produced by elution of chromatography generators with physiological saline solutions. The analysis with the 18.41 keV K α line of Technetium was accomplished with monochromatized K α radiation from a silver anode x-ray tube operated at 45 keV and 20 mA. This radiation at 22.104 keV is efficiently coupled to the 21.054 keV absorption edge of Tc. It is also of advantage in the direct analysis of organic and saline properties of the Tc-bearing samples. Quantification was accomplished by internal standard addition of Ga and using an interpolated value of the sensitivity for Tc between Molybdenum and Rhenium. Data processing was carried out with the QXAS-AXIL software package. System sensitivity was found adequate for direct Tc determination of eluted saline solutions. The interest and advantages of the use of the technique as an auxiliary in the synthesis and characterization of Tc-labeled radiopharmaceuticals used for diagnosis in nuclear medicine are discussed. Detection limits in the matrices analyzed are reported. (author)

  9. Sensitive determination of nucleic acids using organic nanoparticle fluorescence probes

    Zhou, Yunyou; Bian, Guirong; Wang, Leyu; Dong, Ling; Wang, Lun; Kan, Jian

    2005-06-01

    This paper describes the preparation of organic nanoparticles by reprecipitation method under sonication and vigorous stirring. Transmission electron microscopy (TEM) was used to characterize the size and size distribution of the luminescent nanoparticles. Their average diameter was about 25 nm with a size variation of ±18%. The fluorescence decay lifetime of the nanoparticles also was determined on a self-equipped fluorospectrometer with laser light source. The lifetime (˜0.09 μs) of nanoparticles is about three times long as that of the monomer. The nanoparticles were in abundant of hydrophilic groups, which increased their miscibility in aqueous solution. These organic nanoparticles have high photochemical stability, excellent resistance to chemical degradation and photodegradation, and a good fluorescence quantum yield (25%). The fluorescence can be efficiently quenched by nucleic acids. Based on the fluorescence quenching of nanoparticles, a fluorescence quenching method was developed for determination of microamounts of nucleic acids by using the nanoparticles as a new fluorescent probe. Under optimal conditions, maximum fluorescence quenching is produced, with maximum excitation and emission wavelengths of 345 and 402 nm, respectively. Under optimal conditions, the calibration graphs are linear over the range 0.4-19.0 μg ml -1 for calf thymus DNA (ct-DNA) and 0.3-19.0 μg ml -1 for fish sperm DNA (fs-DNA). The corresponding detection limits are 0.25 μg ml -1 for ct-DNA and 0.17 μg ml -1 for fs-DNA. The relative standard deviation of six replicate measurements is 1.3-2.1%. The method is simple, rapid and sensitive with wide linear range. The recovery and relative standard deviation are very satisfactory.

  10. Preliminary determination of calcium, phosphorus, and the calcium/phosphorus ratio in cortical bone of Chinstrap penguin using synchrotron X-ray fluorescence analysis

    Xie Zhouqing; Cheng Bangbo; Sun Liguang; Huang Yuying; He Wei; Zhao Sanping

    2006-01-01

    Synchrotron radiation X-ray fluorescence (SR-XRF) approach was applied to analyzing of Chinstrap penguin (Pygoscelis Antarctica) cortical bone. The method enabled the in situ determination of Ca and P concentrations and the Ca/P ratio in cortical bone. The preliminary results show that: (1) there is the bone site-related difference for Ca and P concentrations. The mean values for the investigated parameters ( on a dry-weight basis) are: 30.7% (Ca) and 14.9% (P) for the femoral cortical bone, 21.4% (Ca) and 11.5% (P) for wing cortical bone. (2) The variation for the Ca/P ratio in cortical bone is lower than those for Ca and P separately.This is in agreement with the previous report that the specificity of the Ca/P ratio is better than that of Ca and P concentrations and is more reliable for the diagnosis of bone disorders. The authors suggest that further studies be conducted to establish normal values of Ca, P and Ca/P ratio for polar animals and provide a basis for the diagnosis of bone disorders.

  11. Fluorescent sensing and determination of mercury (II) ions in water ...

    In this study we report on a fluorescent sensing probe based on a naphthyl azo dye modified dibenzo-18-crown-6-ether (DB18C6) for the detection and determination of mercury (II) ions in water. The probe showed high sensitivity and selectivity towards the mercury (II) ion among various alkali, alkaline earth, and transition ...

  12. Using chlorophyll fluorescence to determine stress in Eucalyptus ...

    Using chlorophyll fluorescence to determine stress in Eucalyptus grandis seedlings: scientific paper. ... Southern Forests: a Journal of Forest Science ... factors affect the functioning of the photosynthetic system, the status of the photosynthetic apparatus is a good indicator of the plant in terms of stress and stress adaptation.

  13. X-ray fluorescence spectroscopic determination of heavy metals and ...

    Purpose: To determine the heavy metal and trace element composition of the powdered aerial parts of Origanum sipyleum L. and its water extract. Methods: The heavy metal and trace elements content of the powdered plant material and 2 % aqueous extract were evaluated by x-ray fluorescence spectroscopy with silicon ...

  14. Simultaneous determination of glycols based on fluorescence anisotropy

    Garcia Sanchez, F.; Navas Diaz, A.; Lopez Guerrero, M.M.

    2007-01-01

    Simultaneous determination of non-fluorescent glycols in mixtures without separation or chemical transformation steps is described. Two methods based in the measure of fluorescence anisotropy of a probe such as fluorescein dissolved in the analyte or analyte mixtures are described. In the first method, the anisotropy spectra of pure and mixtures of analytes are used to quantitative determination (if the fluorophor concentration is in a range where fluorescence intensity is proportional to concentration). In the second method, a calibration curve anisotropy-concentration based on the application of the Perrin equation is established. The methods presented here are capable of directly resolving binary mixtures of non-fluorescent glycols on the basis of differences on the fluorescence anisotropy of a fluorescence tracer. Best analytical performances were obtained by application of the method based on Perrin equation. This method is simple, rapid and allows the determination of mixtures of glycols with reasonable accuracy and precision. Detection limits are limited by the quantum yield and anisotropy values of the tracer in the solvents. Recovery values are related to the differences in anisotropy values of the tracer in the pure solvents. Mixtures of glycerine/ethylene glycol (GL/EG), ethylene glycol/1,2-propane diol (EG/1,2-PPD) and polyethylene glycol 400/1,2-propane diol (PEG 400/1,2-PPD) were analysed and recovery values are within 95-120% in the Perrin method. Relative standard deviation are in the range 1.3-2.9% and detection limits in the range 3.9-8.9%

  15. X-ray fluorescence determination of cobalt in iron-manganese oceanic concretions

    Ivanenko, V.V.; Kustov, V.N.; Metelev, A.Yu.; Rakita, K.A.

    1989-01-01

    A method was developed for resolution of weak analytical lines for elements determined by radionuclide-excited X-ray fluorescence multi-element analysis. The method was used aboart for determining cobalt and some other commercially valuable elements in iron-manganese concretions of Pacific ocean 109 Cd was used as an ionizing radiation source

  16. Rotationally cooled laser induced fluorescence determination of polycyclic aromatic hydrocarbons

    Warren, J.A.; Hayes, J.M.; Small, G.J.

    1982-01-01

    In recent years the development of new highly selective and sensitive methods for the characterization and determination of polycyclic aromatic hydrocarbons (PAHs) and their derivatives in complex mixtures has received considerable attention. High selectivity is associated here with the ability to distinguish between substitutional isomers of PAHs. Attainment of this selectivity with capillary column-gas chromatography-mass spectrometry for complex mixtures is very difficult and time-consuming. Alternative approaches are, therefore, required. Given that the majority of PAHs fluoresce with reasonable quantum yields and that high sensitivities are afforded by fluorescence detection, the possibility of developing high-resolution fluorescence based techniques is attractive. This is all the more so if the technique's selectivity does not rely on physical separation, e.g., chromatography. In this paper discussion is limited to such techniques

  17. Quantitative x-ray fluorescent analysis using fundamental parameters

    Sparks, C.J. Jr.

    1976-01-01

    A monochromatic source of x-rays for sample excitation permits the use of pure elemental standards and relatively simple calculations to convert the measured fluorescent intensities to an absolute basis of weight per unit weight of sample. Only the mass absorption coefficients of the sample for the exciting and the fluorescent radiation need be determined. Besides the direct measurement of these absorption coefficients in the sample, other techniques are considered which require fewer sample manipulations and measurements. These fundamental parameters methods permit quantitative analysis without recourse to the time-consuming process of preparing nearly identical standards

  18. [Fluorescence spectra analysis of the scrophularia soup].

    Yan, Li-hua; Song, Feng; Han, Juan; Su, Jing; Qu, Fei-fei; Song, Yi-zhan; Hu, Bo-lin; Tian, Jian-guo

    2008-08-01

    The cold-water and boiled-water soaked scrophularia soups have been prepared. The emission and excitation spectra of each scrophularia soup under different conditions have been measured at room temperature. The pH values of the different scrophularia soups have been also detected. There are obvious differences between the cold-water soaked scrophularia soup and the boiled-water soaked scrophularia. For both soups the emission wavelength increases with the wavelength of the excitation, but the peaks of the emission spectra for cold-water and boiled-water soaked scrophularia soup are different, which are 441 and 532 nm, respectively. Excitation spectrum has double peaks in the cold-water soaked scrophularia soup while only one peak with longer wavelength in the boiled-water soaked one. The pH value changes from 5.5 to 4.1. According to the organic admixture fluorescence mechanism we analyzed the reasons of the experimental results. Through heating, the interaction in different fluorescence molecular and the energy transfer process in the same fluorescence molecular become more active, and the conjugate structures and the generation of hydrogen bonds, increase. The fluorescence measurement is of value for the scrophularia pharmacology analysis and provides an analytical method for the quality identification of scrophularia soup.

  19. Fluorescent determination of graphene quantum dots in water samples

    Benítez-Martínez, Sandra; Valcárcel, Miguel, E-mail: qa1meobj@uco.es

    2015-10-08

    This work presents a simple, fast and sensitive method for the preconcentration and quantification of graphene quantum dots (GQDs) in aqueous samples. GQDs are considered an object of analysis (analyte) not an analytical tool which is the most frequent situation in Analytical Nanoscience and Nanotechnology. This approach is based on the preconcentration of graphene quantum dots on an anion exchange sorbent by solid phase extraction and their subsequent elution prior fluorimetric analysis of the solution containing graphene quantum dots. Parameters of the extraction procedure such as sample volume, type of solvent, sample pH, sample flow rate and elution conditions were investigated in order to achieve extraction efficiency. The limits of detection and quantification were 7.5 μg L{sup −1} and 25 μg L{sup −1}, respectively. The precision for 200 μg L{sup −1}, expressed as %RSD, was 2.8%. Recoveries percentages between 86.9 and 103.9% were obtained for two different concentration levels. Interferences from other nanoparticles were studied and no significant changes were observed at the concentration levels tested. Consequently, the optimized procedure has great potential to be applied to the determination of graphene quantum dots at trace levels in drinking and environmental waters. - Highlights: • Development of a novel and simple method for determination of graphene quantum dots. • Preconcentration of graphene quantum dots by solid phase extraction. • Fluorescence spectroscopy allows fast measurements. • High sensitivity and great reproducibility are achieved.

  20. Mercury mass measurement in fluorescent lamps via neutron activation analysis

    Viererbl, L.; Vinš, M.; Lahodová, Z.; Fuksa, A.; Kučera, J.; Koleška, M.; Voljanskij, A.

    2015-11-01

    Mercury is an essential component of fluorescent lamps. Not all fluorescent lamps are recycled, resulting in contamination of the environment with toxic mercury, making measurement of the mercury mass used in fluorescent lamps important. Mercury mass measurement of lamps via instrumental neutron activation analysis (NAA) was tested under various conditions in the LVR-15 research reactor. Fluorescent lamps were irradiated in different positions in vertical irradiation channels and a horizontal channel in neutron fields with total fluence rates from 3×108 cm-2 s-1 to 1014 cm-2 s-1. The 202Hg(n,γ)203Hg nuclear reaction was used for mercury mass evaluation. Activities of 203Hg and others induced radionuclides were measured via gamma spectrometry with an HPGe detector at various times after irradiation. Standards containing an Hg2Cl2 compound were used to determine mercury mass. Problems arise from the presence of elements with a large effective cross section in luminescent material (europium, antimony and gadolinium) and glass (boron). The paper describes optimization of the NAA procedure in the LVR-15 research reactor with particular attention to influence of neutron self-absorption in fluorescent lamps.

  1. X-Ray fluorescence determination of the mobile forms of toxic elements in meadow chernozems

    Belikov, K.N.; Blank, A.B.; Shevtsov, N.I.

    1997-01-01

    An X-ray fluorescence method for determining mobile forms of Mn, V, Cr, Co, Ni, Zn, and Pb in meadow chernozems was developed. It is based on the extraction of analytes with an acetate-ammonia buffer solution and the evaporation of the obtained filtrate with carbon powder followed by the X-ray fluorescence analysis of the dry residue. The effect of concomitants on the analytical signals of elements under determination was examined. It was suggested to spike samples with barium in order to decrease analytical errors. (author)

  2. Fluorescence uranium determination; Determinacion de uranio por fluorescencia. I. Proyecto de equipo y comprobacion

    Fernandez Cellini, R; Crus Castillo, F. de la; Barrera Pinero, R

    1960-07-01

    An equipment for analysis of uranium by fluorescence was developed in order to determine it at such a low concentration that it can not be determined by the most sensible analytical methods. this new fluorimeter was adapted to measure the fluorescence emitted by the phosphorus sodium fluoride-sodium carbonate-potasium carbonate-uranyl, being excited by ultraviolet light of 3,650 A the intensity of the light emitted was measure with a photomultiplicator RCA 5819 and the adequate electronic equipment. (Author) 19 refs.

  3. Rapid fluorometric determination of perfluorooctanoic acid by its quenching effect on the fluorescence of quantum dots

    Liu, Qi; Huang, Aizhen; Wang, Nan; Zheng, Guan; Zhu, Lihua

    2015-01-01

    Analysis of perfluorooctanoic acid (PFOA) usually requires a combination of high-performance liquid chromatography and mass spectrometry, which is expensive and time-consuming. In the present work, water-soluble CdS quantum dots (QDs) were employed to develop a simple and rapid fluorometric method for the determination of PFOA. Strongly fluorescent CdS QDs were prepared by using 3-mercaptopropionic acid (MPA) as a stabilizer. It was observed that PFOA strongly quenched the fluorescence emission of the MPA-CdS QDs because PFOA promotes the aggregation of MPA-CdS QDs through a fluorine–fluorine affinity interaction. Under optimum conditions, the fluorescence intensity of MPA-CdS QDs was observed to decrease linearly with an increase in the concentration of PFOA from 0.5 to 40 μmol L −1 , with a limit of detection of 0.3 μmol L −1 . This new method was successfully implemented for the analysis of PFOA-spiked textile samples, with recoveries ranging from 95% to 113%. - Highlights: • PFOA significantly quenched the fluorescence emission of quantum dots (QDs). • A rapid and simple fluorescence sensor was proposed for determining PFOA by QDs. • PFOA determination could be completed within approximately 10 min. • The developed method had a working range of 0.5 to 40 μmol L −1 and a detection limit of 0.3 μmol L −1

  4. Total reflection X-ray fluorescence analysis

    Michaelis, W.; Prange, A.

    1987-01-01

    In the past few years, total reflection X-ray flourescence analysis (TXRF) has found an increasing number of assignments and applications. Experience of trace element analysis using TXRF and examples of applications are already widespread. Therefore, users of TXRF had the opportunity of an intensive exchange of their experience at the 1st workshop on total reflection X-ray fluorescence analysis which took place on May 27th and 28th 1986 at the GKSS Research Centre at Geesthacht. In a series of lectures and discussions dealing with the analytical principle itself, sample preparation techniques and applications as well as comuter programs for spectrum evaluation, the present state of development and the range of applications were outlined. 3 studies out of a total of 14 were included separately in the INIS and ENERGY databases. With 61 figs., 12 tabs [de

  5. [Analysis of fluorescence spectrum of petroleum-polluted water].

    Huang, Miao-Fen; Song, Qing-Jun; Xing, Xu-Feng; Jian, Wei-Jun; Liu, Yuan; Zhao, Zu-Long

    2014-09-01

    In four ratio experiments, natural waters, sampled from the mountain reservoir and the sea water around Dalian city, were mixed with the sewage from petroleum refinery and petroleum exploitation plants. The fluorescence spectra of water samples containing only chromophoric dissolved organic matters(CDOM), samples containing only petroleum, and samples containing a mixture of petroleum and CDOM were analyzed, respectively. The purpose of this analysis is to provide a basis for determining the contribution of petroleum substances and CDOM to the total absorption coefficient of the petroleum-contaminated water by using fluorescence technique. The results showed that firstly, CDOM in seawater had three main fluorescence peaks at Ex: 225-230 nm/Em: 320-330 nm, Ex: 280 nm/Em: 340 nm and Ex: 225-240 nm/Em: 430-470 nm, respectively, and these may arise from the oceanic chlorophyll. CDOM in natural reservoir water had two main fluorescence peaks at EX: 240- 260 nm/Em: 420-450 nm and Ex: 310~350 nm/Em: 420--440 nm, respectively, and these may arise from the terrestrial sources; secondly, the water samples containing only petroleum extracted with n-hexane had one to three fluorescence spectral peaksat Ex: 220-240 nm/Em: 320-340 nm, Ex: 270-290 nm/Em: 310-340 nm and Ex: 220-235 nm/Em: 280-310 nm, respectively, caused by their hydrocarbon component; finally, the water samples containing both petroleum and CDOM showed a very strong fluorescence peak at Ex: 230-250 nm/Em: 320-370 nm, caused by the combined effect of CDOM and petroleum hydrocarbons.

  6. Choice of excitation source for determination of rare earth elements with radioisotope excited X ray fluorescence

    Zhang Quanshi; Chang Yongfu

    2000-01-01

    The comparisons of two radioisotope source ( 241 Am and 238 Pu) which are the most available in the radioisotope excited X Ray Fluorescence (XRF) analysis technique and two characteristic X ray series (KX and LX) analyzed for the determination of the rare-earth (RE) elements were investigated in detail. According to the principle of emission and detection of X ray , the relative excitation efficiencies were calculated by the some fundamental physical parameters including the photoelectric mass attenuation coefficient, the fluorescent yield, the absorption jump factor, the emission probability of the detected fluorescent line with reference to other liens of the same series etc., The advantages and disadvantages of the two conditions are discussed. These results may determine the optimal excitation and detection conditions for different rare-earth elements. The experimental results with nine rare-earth elements (Ce, Nd, Sm, Tb, Tm, Ho, Er, Yb and Lu) are in agreement with the results of theoretical calculations

  7. Quantum dots (QDs) based fluorescence probe for the sensitive determination of kaempferol

    Tan, Xuanping; Liu, Shaopu; Shen, Yizhong; He, Youqiu; Yang, Jidong

    2014-12-01

    In this work, using the quenching of fluorescence of thioglycollic acid (TGA)-capped CdTe quantum dots (QDs), a novel method for the determination of kaempferol (KAE) has been developed. Under optimum conditions, a linear calibration plot of the quenched fluorescence intensity at 552 nm against the concentration of KAE was observed in the range of 4-44 μg mL-1 with a detection limit (3σ/K) of 0.79 μg mL-1. In addition, the detailed reaction mechanism has also been proposed on the basis of electron transfer supported by ultraviolet-visible (UV-vis) absorption and fluorescence (FL) spectroscopy. The method has been applied for the determination of KAE in pharmaceutical preparations with satisfactory results. The proposed method manifested several advantages such as high sensitivity, short analysis time, low cost and ease of operation.

  8. In vivo X-ray fluorescence analysis

    Ahlgren, L.

    1980-02-01

    Measurements on five occupationally exposed persons have shown that it is possible to use X-ray fluorescence analysis for in vivo measurements of lead in the skeleton. The technique for calibrating in vivo X-ray fluorescence measurements of lead in bone tissue has been studied in detail and a two-component phantom simulating the bone and the soft tissue parts of the finger constructed. The technique has been used for in vivo measurements on 22 occupationally exposed persons. The minimum detectable concentration of lead in fingerbones was found to be around 20 μg x g -1 . The lead concentrations in their skeletons and blood were compared: the correlation was poor. The variations in lead concentrations in the skeleton have been studied in occupationally exposed persons and in samples from archaeological skeletons. The sensitivity and the minimum detectable concentration of cadmium in the kidney cortex in in vivo measurements has been studied by measurements on kidney models. The minimum detectable concentration was 20 μg x g -1 at a skin-kidney distance of 30 mm and 40 μg x g -1 at 40 mm. Five persons occupationally exposed were studied. (Author)

  9. A dihydrazone based fluorescent probe for selective determination of Al{sup 3+} ions

    Pratap Singh, Divya; Singh, Vinod P., E-mail: singvp@yahoo.co.in

    2014-11-15

    A highly selective fluorescent sensor N,N′-bis((2-hydroxynaphthalen-1-yl)methylene) oxalohydrazide (H{sub 2}ohn) for the determination of Al{sup 3+} ions was synthesized and characterized by different physico-chemical and spectroscopic techniques. The single crystal structure of H{sub 2}ohn receptor has also been reported. The H{sub 2}ohn shows an enhanced fluorescence in the presence of Al{sup 3+} ions in ethanol–water (2:3 v/v) solution. Other cations viz. Na{sup +}, K{sup +}, Mg{sup 2+}, Ca{sup 2+}, Mn{sup 2+}, Fe{sup 3+}, Co{sup 2+}, Ni{sup 2+}, Cu{sup 2+}, Zn{sup 2+}, Pb{sup 2+}, Cd{sup 2+} and Hg{sup 2+} show no appreciable change in fluorescence intensity. The binding mode of H{sub 2}ohn receptor with Al{sup 3+} was studied by UV–visible, fluorescence and {sup 1}H NMR titrations. The receptor acts as a dibasic hexadentate ligand and interacts with two Al{sup 3+} ions with a high binding constant K{sub B}=2.62×10{sup 11} M{sup −2}. The lowest detection limit for Al{sup 3+} complex of H{sub 2}ohn was determined to be 8.56×10{sup −10} M. The structures of H{sub 2}ohn and its Al(III) complex were also optimized by DFT calculations. - Highlights: • A dihydrazone based fluorescent sensor is synthesized. • Characterized by IR, NMR, UV−visible and mass spectral analysis. • The receptor serves as a selective fluorescent sensor for Al{sup 3+} over other cations. • The sensing property is monitored by UV−visible, fluorescence and NMR spectroscopy. • A high binding constant of the receptor with Al{sup 3+} is reported here.

  10. X-ray fluorescence method for trace analysis and imaging

    Hayakawa, Shinjiro

    2000-01-01

    X-ray fluorescence analysis has a long history as conventional bulk elemental analysis with medium sensitivity. However, with the use of synchrotron radiation x-ray fluorescence method has become a unique analytical technique which can provide tace elemental information with the spatial resolution. To obtain quantitative information of trace elemental distribution by using the x-ray fluorescence method, theoretical description of x-ray fluorescence yield is described. Moreover, methods and instruments for trace characterization with a scanning x-ray microprobe are described. (author)

  11. Analysis of sodium metal by X-ray fluorescence spectrometry (I). Determination of Hf, Mo, Nb, Ta, Ti, V and Zr

    Diaz-Guerra, J. P.

    1981-01-01

    A method allowing the determination of trace quantities of Hf, Mo, Nb, Ta, Ti, Vi and Zr in sodium metal previous transformation into Na 2 S0 4 is described. The enrichment of the impurities is performed through a coprecipitation technique in sulfuric medium by using Fe 3 + as a collector and cupferron or phenyfluorone as the precipitating reagent. The matrix influence and the best concentration of the collector (10/μ/ml), adequate pH (1,3 or 4, respectively) and optimum filter type (Millipore BSWP02500 or BDWP04700, respectively) have been studied, as well as the precipitation recoveries corresponding to the reagent above. It has been demonstrated the batter efficiency of the cupferron for determining all the Impurities. Detection limits range from 0.01 to 0.2 ppm., depending on the element, for samples 4 g in weight. An automatic spectrometer attached to a 16 K minicomputer and X-ray tube with a gold anode (2250-2700 W) are used. The Interferences between the lines ZrKα (2 n d order) - HfLα and TiKβ - VK α have been studied and the respective correction coefficients have been deduced. (Author) 8 refs

  12. Zinc content determination in rice and other agriproducts by X-ray fluorescence

    Denis Alpizar, Otoniel; Diaz Rizo, Oscar

    2009-01-01

    The Zn content in regular consumption foodstuff (rice, some vegetables and roots) in Cuba is reported. Concentrations are determined by X-Ray Fluorescence analysis using a set of organic standards doped with Zn. The accuracy of the analytical procedure was validated using the Certified Reference Materials IAEA 393 and y MA-B-3/TM. The obtained results show rice as the major Zn bioaccumulator of the studied agriproducts and the main Zn source in Cuban human diet. (author)

  13. Zinc content determination in rice and other agricultural products by X-ray fluorescence

    Denis Alpizar, Otoniel; Diaz Rizo, Oscar

    2010-01-01

    The Zn content in regular consumption foodstuff (rice, some vegetables and roots) in Cuba is reported. Concentrations are determined by X-Ray Fluorescence analysis using a set of organic standards doped with Zn. The accuracy of the analytical procedure was validated using the Certified Reference Materials IAEA 393 and y MA-B-3/TM. The obtained results show rice as the major Zn bioaccumulator of the studied agricultural products and the main Zn source in Cuban human diet. (author)

  14. Determination of calcium and iron in limestone by X-ray fluorescence method

    Sovtsova, M.K.

    1977-01-01

    The results of determining calcium and iron content in limestone by X-ray fluorescence method are described. The 109 Cd isotape was chosen as a source for excitation, as it permited to reduce the concentration degeneration in the range of large Ca contents due to the larger energy of the primary radiation. The root-mean-square deviation from the data of chemical analysis was +-0.02%FeO and +-0.22%CaO

  15. Rapid fluorometric determination of perfluorooctanoic acid by its quenching effect on the fluorescence of quantum dots

    Liu, Qi; Huang, Aizhen; Wang, Nan, E-mail: nwang@hust.edu.cn; Zheng, Guan; Zhu, Lihua

    2015-05-15

    Analysis of perfluorooctanoic acid (PFOA) usually requires a combination of high-performance liquid chromatography and mass spectrometry, which is expensive and time-consuming. In the present work, water-soluble CdS quantum dots (QDs) were employed to develop a simple and rapid fluorometric method for the determination of PFOA. Strongly fluorescent CdS QDs were prepared by using 3-mercaptopropionic acid (MPA) as a stabilizer. It was observed that PFOA strongly quenched the fluorescence emission of the MPA-CdS QDs because PFOA promotes the aggregation of MPA-CdS QDs through a fluorine–fluorine affinity interaction. Under optimum conditions, the fluorescence intensity of MPA-CdS QDs was observed to decrease linearly with an increase in the concentration of PFOA from 0.5 to 40 μmol L{sup −1}, with a limit of detection of 0.3 μmol L{sup −1}. This new method was successfully implemented for the analysis of PFOA-spiked textile samples, with recoveries ranging from 95% to 113%. - Highlights: • PFOA significantly quenched the fluorescence emission of quantum dots (QDs). • A rapid and simple fluorescence sensor was proposed for determining PFOA by QDs. • PFOA determination could be completed within approximately 10 min. • The developed method had a working range of 0.5 to 40 μmol L{sup −1} and a detection limit of 0.3 μmol L{sup −1}.

  16. Study of the elemental composition of Chenopodium Quinoa Willd by fast neutron activation analysis and X ray fluorescence analysis

    Soto Moran, R.L.; Szegedi, S.; Llopiz, J.L.

    1996-01-01

    By means of x-ray fluorescence and fast neutron activation analysis the nitrogen content has been determined in samples of roots, stems, leaf, flowers and grains from Quinua (Chenopodium Quinoa Willd), which was previously treated with fertilizer

  17. Trace elements determination in red and white wines using total-reflection X-ray fluorescence

    Anjos, M.J.; Lopes, R.T.; Jesus, E.F.O. de; Moreira, S.; Barroso, R.C.; Castro, C.R.F.

    2003-01-01

    Several wines produced in different regions from south of Brazil and available in markets in Rio de Janeiro were analyzed for their contents of elements such as: P, S, Cl, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Rb and Sr. Multi-element analysis was possible with simple sample preparation and subsequent analysis by total-reflection X-ray fluorescence using synchrotron radiation. The measurement was carried at the X-ray fluorescence beamline in the Synchrotron Light Source Laboratory in Campinas, Brazil. The levels of the various elements obtained were lower in the Brazilian wines than the values generally found in the literature. The present study indicates the capability of multi-element analysis for determining the contents of various elements present in wines coming from Brazil vineyards by using a simple, sensitive and precise method

  18. Determining the ice-binding planes of antifreeze proteins by fluorescence-based ice plane affinity.

    Basu, Koli; Garnham, Christopher P; Nishimiya, Yoshiyuki; Tsuda, Sakae; Braslavsky, Ido; Davies, Peter

    2014-01-15

    Antifreeze proteins (AFPs) are expressed in a variety of cold-hardy organisms to prevent or slow internal ice growth. AFPs bind to specific planes of ice through their ice-binding surfaces. Fluorescence-based ice plane affinity (FIPA) analysis is a modified technique used to determine the ice planes to which the AFPs bind. FIPA is based on the original ice-etching method for determining AFP-bound ice-planes. It produces clearer images in a shortened experimental time. In FIPA analysis, AFPs are fluorescently labeled with a chimeric tag or a covalent dye then slowly incorporated into a macroscopic single ice crystal, which has been preformed into a hemisphere and oriented to determine the a- and c-axes. The AFP-bound ice hemisphere is imaged under UV light to visualize AFP-bound planes using filters to block out nonspecific light. Fluorescent labeling of the AFPs allows real-time monitoring of AFP adsorption into ice. The labels have been found not to influence the planes to which AFPs bind. FIPA analysis also introduces the option to bind more than one differently tagged AFP on the same single ice crystal to help differentiate their binding planes. These applications of FIPA are helping to advance our understanding of how AFPs bind to ice to halt its growth and why many AFP-producing organisms express multiple AFP isoforms.

  19. Sheet Fluorescence and Annular Analysis of Ultracold Neutral Plasmas

    Castro, J.; Gao, H.; Killian, T. C.

    2009-01-01

    Annular analysis of fluorescence imaging measurements on Ultracold Neutral Plasmas (UNPs) is demonstrated. Spatially-resolved fluorescence imaging of the strontium ions produces a spectrum that is Doppler-broadened due to the thermal ion velocity and shifted due to the ion expansion velocity. The fluorescence excitation beam is spatially narrowed into a sheet, allowing for localized analysis of ion temperatures within a volume of the plasma with small density variation. Annular analysis of fluorescence images permits an enhanced signal-to-noise ratio compared to previous fluorescence measurements done in strontium UNPs. Using this technique and analysis, plasma ion temperatures are measured and shown to display characteristics of plasmas with strong coupling such as disorder induced heating and kinetic energy oscillations.

  20. Detection of Colorectal Cancer by a Quantitative Fluorescence Determination of DNA Amplification in Stool

    Daniele Calistri

    2004-09-01

    Full Text Available DNA amplification of exfoliated cells in stool repre sents an inexpensive and rapid test, but has only 50% to 60% sensitivity. A new quantitative method, calle( fluorescence long DNA, was developed and validate( in our laboratory on stool obtained from 86 patient., with primary colorectal cancer and from 62 health individuals. It consists of the amplification of stoo DNA with fluorescence primers and the quantification of the amplification using a standard curve. Results are arbitrarily expressed in nanograms. The potential of thi new method compared to the conventional approact was analyzed in a subgroup of 94 individuals (51 patients and 38 healthy volunteers. In the presen series, DNA amplification analysis showed a specific ity of 97% and a sensitivity of only 50%. Conversely fluorescence DNA evaluation, using the best cutoff o 25 ng, showed a sensitivity of about 76% and a spec ificity of 93%. Similar sensitivity was observed regard less of Dukes stage, tumor location, and size, thu., also permitting the detection of early-stage tumors The present study seems to indicate that quantitative fluorescence DNA determination in stool successfully identifies colorectal cancer patients with a sensitivity comparable, if not superior, to that of multiple gene analysis but at a lower cost and in a shorter time.

  1. The fluorescence properties and NMR analysis of protopine and allocryptopine

    Kubala, Martin; Vacek, Jan; Popa, Igor; Janovska, Marika; Kosina, Pavel; Ulrichova, Jitka; Travnicek, Zdenek; Simanek, Vilim

    2011-01-01

    The fluorescence properties of protopine and allocryptopine in aqueous and organic environments are described for the first time. The fluorescence of alkaloids and their pH-dependent interconversion to cationic forms (transannular interaction) were studied using steady-state and time-resolved fluorescence techniques. For the analysis of tricyclic base and cis/trans tetracyclic cations of the alkaloids, NMR and X-ray crystallography were used. - Highlights: → We describe fundamental fluorescence characteristics of alkaloids protopine and allocryptopine. → We analyzed the pH-dependent transitions and cis/trans isomerization. → These two alkaloids can be better distinguished by their fluorescence decay characteristics. → The fluorescence parameters are related to the NMR and crystallographic structural data.

  2. Applications of optical fiber to the remote fluorescence analysis

    Shin, Jang Soo; Kim, Duck Hueon; Lee, Soo Ho

    1992-12-01

    The laser fluorometer developed in 1987 has been used in real circumstances for trace uranium analysis. And, we have been trying to improve the instrument to be able to apply in analytical circumstances of remote measurement using optical fiber. The N 2 laser beam and the resulting fluorescence light could be successfully transmitted through a quartz-made optical fiber. The wavelength resolution and the fluorescence decay time resolution induced by pulsed N 2 laser were used to the uranium fluorescence analyses. The fluorescence of uranium in nitric acid medium was measured successfully using the system. The fluorescence signal was analysed using simplex method which is useful to deconvolute the mixed signals. An analytical method using thermal lens effect was developed. The method will be a complementary one for the fluorescence measurement. (Author)

  3. Use of X-ray fluorescence for metal determination in polymers

    Guidorizzi, Lorenza

    1996-01-01

    X-Ray fluorescence spectrometry was used to determine metals and non-metals in polyester polymers. The greatest advantage of this technique over others like Atomic Absorption or Plasma Emission is that no sample previous treatment (like calcination or acid digestion) is required. Other advantage of this method is its fastness allowing a complete analysis in just few minutes. On the other hand, this method requires metals higher than 15 ppm. Below those values there is a loss of the analysis' precision. Another advantage of this technique is the possibility of making qualitative metal analysis, scanning unknown samples and identifying the found peaks automatically. (author)

  4. High sensitive determination of zinc with novel water-soluble small molecular fluorescent sensor

    Weng Ying; Chen Zilin; Wang Fang; Xue Lin; Jiang Hua

    2009-01-01

    A high sensitive method of quantitative analysis for the determination of zinc in the nutrition supplements has been developed by using a novel water-soluble fluorescent sensor HQ3: (8-pyridylmethyloxy-2-methyl-quinoline). Under the optimized condition of 67 mM phosphate buffer, pH 7.4, and 5% (v/v) DMSO, the zinc concentration showed good linear relationship with fluorescence intensity in the range of 7.5 x 10 -8 to 2.5 x 10 -5 M with the detection limit of 1.5 x 10 -8 M. HQ3 exhibited high selectivity to zinc comparing with other metal ions except for cadmium. The developed analytical method was successfully used for determining the content of zinc in a real sample of zinc gluconate solution of Sanchine.

  5. Rapid determination of ampicillin in bovine milk by liquid chromatography with fluorescence detection

    Ang, C.Y.W.; Luo, Wenhong [National Center for Toxicological Research, Jefferson, AR (United States)

    1997-01-01

    A rapid and sensitive liquid chromatographic (LC) method was developed for the determination of ampicillin residues in raw bovine milk, processed skim milk, and pasteurized, homogenized whole milk with vitamin D. Milk samples were deproteinized with trichloroacetic acid (TCA) and acetonictrile. After centrifugation, the clear supernatant was reacted with formaldehyde and TCA under heat. The major fluorescent derivative of ampicillin was then determined by reversed-phase LC with fluorescence detection. Average recoveries of ampicillin fortified at 5, 10, and 20 ppb (ng/mL) were all >85% with coefficients of variation <10%. Limits of detection ranged from 0.31 to 0.51 ppb and limits of quantitation, from 0.66 to 1.2 ppb. After appropriate validation, this method should be suitable for rapid analysis of milk for ampicillin residues at the tolerance level of 10 ppb. 16 refs., 4 figs., 3 tabs.

  6. X-ray fluorescence analysis of Fe - Ni - Mo systems

    Belyaev, E.E.; Ershov, A.V.; Mashin, A.I.; Mashin, N.I.; Rudnevskij, N.K.

    1998-01-01

    Procedures for the X-ray fluorescence determination of the composition and thickness of Fe - Ni - Mo thin films and the concentration of elements in thick films of the Fe - Ni - Mo alloy are developed [ru

  7. Optimization of a spectrometry for energy-dispersive x-ray fluorescence analysis by x-ray tube in combination with secondary target for multielements determination of sediment samples

    Zaidi Embong; Husin Wagiran

    1997-01-01

    The design of an energy-dispersive X-ray fluorescence spectrometer equipped with a conventional X-ray tube and secondary target is described. The spectrometer system constructed in our laboratory consists of a semiconductor detector system, irradiation chamber and X-ray tube. Primary source from X-ray tube was used to produced secondary X-ray from selenium, molybdenum and cadmium targets. The fluorescence X-ray from the sample was detected using Si(Li) detector with resolution of 0. 175 keV (Mn-K(x). The spectrometer was used for determination of multi-elements with atomic number between 20 to 44 in river sediment samples. The X-ray spectrum, from the samples were analysed using computer software which was developed based on Marquardt method. Optimal conditions and detection limits are determined experimentally by variation of excitation parameters for each combination of secondary target and tube voltage

  8. Application of instrumental neutron activation analysis and X-ray fluorescence analysis in art pieces investigation

    Panczyk, E.; Kierzek, J.; Walis, L.; Ligeza, M.

    1996-01-01

    The application of instrumental neutron activation analysis have been shown for the trace element identification in dyes of old painting and other art objects. The recognition of their composition is a important measure for attribution. Also the X-ray fluorescence analysis has been frequently used for examination of art objects. The age determination of the old chinese porcelain is a good example described in the paper. 20 refs, 4 figs

  9. Comparison of N-alkyl acridine orange dyes as fluorescence probes for the determination of cardiolipin

    Kaewsuya, P.; Miller, J.D. [Department of Chemistry and Biochemistry, Miami University, Oxford, OH 45056 (United States); Danielson, N.D. [Department of Chemistry and Biochemistry, Miami University, Oxford, OH 45056 (United States)], E-mail: danielnd@muohio.edu; Sanjeevi, J.; James, P.F. [Department of Zoology, Miami University, Oxford, OH 45056 (United States)

    2008-09-26

    The phospholipid (PL), cardiolipin (CL), is found almost exclusively in the inner membrane of mitochondria and loss of CL is considered as an important indication of cell apoptosis. Previously, 10-N-nonyl acridine orange (NAO) has been used as a fluorescent probe for the visualization of CL in mitochondrial cell membranes and in solution. In this work for the determination of CL, we have synthesized two new fluorescent probes, n-tetradecyl acridine orange (C14-AO), and n-octadecyl acridine orange (C18-AO) by reacting acridine orange with the corresponding n-alkyl bromide. Using excitation and emission wavelengths at about 500 and 525 nm and varying the percentage of methanol in water as the solvent, no interaction between CL and the fluorescent probes at 75% is noted but a proportional quenching of the fluorescence signal by CL is observed at 50% or less for C14-AO and 60% or less for C18-AO. Binding efficiency of these fluorescent probes to CL is compared using dye concentrations of 5, 10, and 20 {mu}M. C18-AO shows a better sensitivity than C14-AO and NAO, respectively, but is less selective. For C14-AO, the detection limit and limit of quantitation are 0.07 and 0.21 {mu}M, respectively, which are better than those previously reported for NAO. One anionic PL, phosphatidic acid, shows some quenching interference to both the C14 and C18 dyes but only at concentrations above the working range for sample analysis. The CL in mitochondrial membrane samples is determined by standard addition using C14-AO. The level of CL in the outer mitochondrial membrane compared to the inner membrane is significantly increased due to the addition of cadmium chloride into the cells causing cell apoptosis.

  10. Thorium determination by X-ray Fluorescence Spectrometry in simulated thorex process solutions

    Yamaura, M.; Matsuda, H.T.

    1989-01-01

    The X-ray fluorescence method for thorium determination in aqueous and organic (TBP-n-dodecane) solutions is described. The thin film-technique for sample preparation and a suitable internal standard have been used. Some parameters as analytical line, internal standard, filter paper, paper geometry, sample volume and measurement conditions were studied. Uranium, fission products, corrosion products and thorex reagent components were studied as interfering elements in the thorium analysis, as well as the matrix effect by using the thorex process simulated solutions the method to thorium determination in irradiated thorium solutions was applied. (M.J.C.) [pt

  11. Uranium concentrate analysis by X-ray fluorescence spectroscopy

    Diaz-Guerra, J.P.; Bayon, A.; Roca, R.

    1978-01-01

    The determination of As, Ca, Fe, Mo, P, S, Si. Th, V and U in uranium concentrates by X-ray fluorescence spectroscopy has been studied. As and U are determined in nitric solutions and for the rest of elements analysis is performed by a bead fusion technique using Li 2 B 4 O 7 and Li 2 CO 3 as fluxes. Although the uranium matrix minimizes the absorption and enhancement effects, because of the content variations of this element it is advisable to operate at a constant level of U 3 O 8 . Despite the high matrix absorption and the large dilution of the samples, sensitivity and speed are found to be satisfactory as the result of the use of a high sensitivity automatic spectrometer. The spectral interferences of Mo on S and P, and of Pb on As have been particularly considered. (author) [es

  12. On-line solid-phase enrichment coupled to packed reactor flow injection analysis in a green analytical procedure to determine low levels of folic acid using fluorescence detection

    Emara Samy

    2012-12-01

    Full Text Available Abstract Background Analysis of folic acid (FA is not an easy task because of its presence in lower concentrations, its lower stability under acidic conditions, and its sensitiveness against light and high temperature. The present study is concerned with the development and validation of an automated environmentally friendly pre-column derivatization combined by solid-phase enrichment (SPEn to determine low levels of FA. Results Cerium (IV trihydroxyhydroperoxide (CTH as a packed oxidant reactor has been used for oxidative cleavage of FA into highly fluorescent product, 2-amino-4-hydroxypteridine-6-carboxylic acid. FA was injected into a carrier stream of 0.04 M phosphate buffer, pH 3.4 at a flow-rate of 0.25 mL/min. The sample zone containing the analyte was passed through the CTH reactor thermostated at 40°C, and the fluorescent product was trapped and enriched on a head of small ODS column (10 mm x 4.6 mm i.d., 5 μm particle size. The enriched product was then back-flush eluted by column-switching from the small ODS column to the detector with a greener mobile phase consisting of ethanol and phosphate buffer (0.04M, pH 3.4 in the ratio of 5:95 (v/v. The eluent was monitored fluorimetrically at emission and excitation wavelengths of 463 and 367 nm, respectively. The calibration graph was linear over concentrations of FA in the range of 1.25-50 ng/mL, with a detection limit of 0.49 ng/mL. Conclusion A new simple and sensitive green analytical procedure including on-line pre-column derivatization combined by SPEn has been developed for the routine quality control and dosage form assay of FA at very low concentration level. The method was a powerful analytical technique that had excellent sensitivity, sufficient accuracy and required relatively simple and inexpensive instrumentation.

  13. Radionuclide X-ray fluorescence determination of Mn, Fe, Cu, Zn and Pb in wastewaters and sludges from wastewater treatment plants in Bratislava (SR)

    Harangozo, M.; Toelgyessy, J.

    1997-01-01

    Radiometric X-ray fluorescence analysis was used for the determination of Mn, Fe, Cu, Zn and Pb in wastewater and sludges from three wastewater treatment plants in Bratislava (SR). Metals were determined in wastewaters after preconcentration by 8-hydroxyquinoline and in sludges by drying and pressing to pellets. 238 Pu and 109 Cd was used for excitation of fluorescence radiation. (author)

  14. Absorption correction factor in X-ray fluorescent quantitative analysis

    Pimjun, S.

    1994-01-01

    An experiment on absorption correction factor in X-ray fluorescent quantitative analysis were carried out. Standard samples were prepared from the mixture of Fe 2 O 3 and tapioca flour at various concentration of Fe 2 O 3 ranging from 5% to 25%. Unknown samples were kaolin containing 3.5% to-50% of Fe 2 O 3 Kaolin samples were diluted with tapioca flour in order to reduce the absorption of FeK α and make them easy to prepare. Pressed samples with 0.150 /cm 2 and 2.76 cm in diameter, were used in the experiment. Absorption correction factor is related to total mass absorption coefficient (χ) which varied with sample composition. In known sample, χ can be calculated by conveniently the formula. However in unknown sample, χ can be determined by Emission-Transmission method. It was found that the relationship between corrected FeK α intensity and contents of Fe 2 O 3 in these samples was linear. This result indicate that this correction factor can be used to adjust the accuracy of X-ray intensity. Therefore, this correction factor is essential in quantitative analysis of elements comprising in any sample by X-ray fluorescent technique

  15. Determination of Ivermectin in Medicated Feeds by Liquid Chromatography with Fluorescence Detection

    2013-01-01

    A labour- and time-effective analytical procedure for determination of ivermectin in medicated feed at recommended level of 2.0 mg kg−1 has been developed and validated. The analyte was extracted from grinded feed samples with acetonitrile and derivatisated with N-methylimidazole and trifluoracetic anhydride. The fluorescent derivatives were analysed by liquid chromatography method using C8 column. The isocratic conditions using acetonitrile, methanol, water, and tetrahydrofuran were applied. Fluorescence detection was performed at 365 nm (excitation) and 475 nm (emission) wavelengths. The total analysis time was 10 min. The validation results of the method (within-laboratory reproducibility 4.0% CV, mean recovery 100.1%) confirm the appropriate precision and accuracy of the developed method. PMID:24453835

  16. X-ray Microprobe for Fluorescence and Diffraction Analysis

    Ice, G.E.

    2005-01-01

    X-ray diffraction (see unit 1.1) and x-ray excited fluorescence analysis are powerful techniques for the nondestructive measurement of crystal structure and chemical composition. X-ray fluorescence analysis is inherently nondestructive with orders of magnitude lower power deposited for the same detectable limit as with fluorescence excited by charged particle probes (Sparks, 1980). X-ray diffraction analysis is sensitive to crystal structure with orders-of-magnitude greater sensitivity to crystallographic strain than electron probes (Rebonato, et al. 1989). When a small-area x-ray microbeam is used as the probe, chemical composition (Z>14), crystal structure, crystalline texture, and crystalline strain distributions can be determined. These distributions can be studied both at the surface of the sample and deep within the sample (Fig. 1). Current state-of-the-art can achieve an ∼1 mm-D x-ray microprobe and an ∼0.1 mm-D x-ray microprobe has been demonstrated (Bilderback, et al., 1994). Despite their great chemical and crystallographic sensitivities, x-ray microprobe techniques have until recently been restricted by inefficient x-ray focusing optics and weak x-ray sources; x-ray microbeam analysis was largely superseded by electron techniques in the 50's. However, interest in x-ray microprobe techniques has now been revived (Howells, et al., 1983; Ice and Sparks, 1984; Chevallier, et al., 1997; Riekel 1992; Thompson, el al., 1992; and Making and Using... 1997) by the development of efficient x-ray focusing optics and ultra-high intensity synchrotron x-ray sources (Buras and Tazzari, 1984; Shenoy, et al., 1988). These advances have increased the achievable microbeam flux by more than 11 orders of magnitude (Fig. 2) (Ice, 1997); the flux in a tunable 1 mm-D beam on a 'so called' 3rd-generation synchrotron source such as the APS can exceed the flux in a fixed-energy mm2 beam on a conventional source. These advances make x-ray microfluorescence and x

  17. 5-ALA induced fluorescent image analysis of actinic keratosis

    Cho, Yong-Jin; Bae, Youngwoo; Choi, Eung-Ho; Jung, Byungjo

    2010-02-01

    In this study, we quantitatively analyzed 5-ALA induced fluorescent images of actinic keratosis using digital fluorescent color and hyperspectral imaging modalities. UV-A was utilized to induce fluorescent images and actinic keratosis (AK) lesions were demarcated from surrounding the normal region with different methods. Eight subjects with AK lesion were participated in this study. In the hyperspectral imaging modality, spectral analysis method was utilized for hyperspectral cube image and AK lesions were demarcated from the normal region. Before image acquisition, we designated biopsy position for histopathology of AK lesion and surrounding normal region. Erythema index (E.I.) values on both regions were calculated from the spectral cube data. Image analysis of subjects resulted in two different groups: the first group with the higher fluorescence signal and E.I. on AK lesion than the normal region; the second group with lower fluorescence signal and without big difference in E.I. between two regions. In fluorescent color image analysis of facial AK, E.I. images were calculated on both normal and AK lesions and compared with the results of hyperspectral imaging modality. The results might indicate that the different intensity of fluorescence and E.I. among the subjects with AK might be interpreted as different phases of morphological and metabolic changes of AK lesions.

  18. Fluorescent silver nanoclusters for ultrasensitive determination of chromium(VI) in aqueous solution

    Zhang, Jian Rong; Zeng, Ai Lian; Luo, Hong Qun; Li, Nian Bing

    2016-01-01

    Highlights: • Fluorescent Ag nanoclusters were first applied to Cr(VI) detection. • The proposed method is simple, rapid, and environmentally friendly. • The sensor shows a wide linear range, low detection limit, and good selectivity. • The system can also be used for the indirect assay of total chromium and Cr(III). • The analyses in real water samples are satisfactory. - Abstract: In this work, a simple and sensitive Cr(VI) sensor is proposed based on fluorescent polyethyleneimine-stabilized Ag nanoclusters, which allows the determination over a wide concentration range of 0.1 nM–3.0 μM and with a detection limit as low as 0.04 nΜ and a good selectivity. The quenching mechanism was discussed in terms of the absorption and fluorescence spectra, suggesting that Cr(VI) is connected to Ag nanoclusters by hydrogen bond between the oxygen atom at the vertex of tetrahedron structure of Cr(VI) and the amino nitrogen of polyethyleneimine that surrounded Ag nanoclusters and electron transfer from Ag nanoclusters to highly electron-deficient Cr(VI) results in fluorescence quenching. Despite the failure to quench the fluorescence efficiently, Cr(III) can also be measured using the proposed Ag nanoclusters by being oxidized to Cr(VI) in alkaline solution (pH ∼9) containing H 2 O 2 . Therefore, our approach could be used to detect Cr(VI), Cr(III) and the total chromium level in aqueous solution. In addition, Cr(VI) analysis in real water samples were satisfactory, indicating this method could be practically promising for chromium measurements.

  19. Preparation of specimens for analysis by: X-ray diffraction and X-ray fluorescence analysis

    Banos L, L.

    2004-01-01

    Specimen preparation is one of the most important requirements in the analysis of samples by X-ray Diffraction and X-ray Fluorescence. This statement is especially true for samples containing different types of materials. There are many forms of specimen suitable for X-ray analysis and the type of the sample as received will generally determine the method of pretreatment. It is convenient to refer to the material received for analysis as the sample, and that, which is actually analyzed as the specimen. The powder Diffraction method assumes that the particles in the specimen are ideally random orientation and that there are enough crystallites in the specimen to achieve a representative intensity distribution for these crystallites. X ray Fluorescence is essentially a comparative method of analysis, it is vital that all standards and unknowns be presented to the spectrometer in a reproducible and identical manner. (Author) 3 refs., 6 figs

  20. Simultaneous analysis of gaseous and particulate sulphur in the atmosphere by x-ray fluorescence spectrometry

    Matsuda, Yatsuka; Mamuro, Tetsuo

    1975-01-01

    An analytical technique for the simultaneous measurements of the atmospheric concentrations of SO 2 gas and sulphur absorbed by aerosol particles has been developed. Aerosol particles are collected on membrane filter and at the same time SO 2 gas is captured on alkali impregnated filter. The sulphur content in each filter is measured by an energy dispersive X -ray fluorescence spectrometer consisting of a Si(Li) semiconductor detector connected to a multi-channel pulse height analyzer and an excitation source of 55 Fe. Two methods are acceptable for the determination of the sulphur content in impregnated filter by X-ray fluorescence analysis. In the first method X-ray fluorescence analysis is made after the collected sulphur gas diffused and distributed uniformly enough throughout the filter, and in the second method X-ray fluorescence analysis gas to be finished before the diffusion of the collected sulphur becomes appreciable. (author)

  1. A set of enhanced green fluorescent protein concatemers for quantitative determination of nuclear localization signal strength.

    Böhm, Jennifer; Thavaraja, Ramya; Giehler, Susanne; Nalaskowski, Marcus M

    2017-09-15

    Regulated transport of proteins between nucleus and cytoplasm is an important process in the eukaryotic cell. In most cases, active nucleo-cytoplasmic protein transport is mediated by nuclear localization signal (NLS) and/or nuclear export signal (NES) motifs. In this study, we developed a set of vectors expressing enhanced GFP (EGFP) concatemers ranging from 2 to 12 subunits (2xEGFP to 12xEGFP) for analysis of NLS strength. As shown by in gel GFP fluorescence analysis and αGFP Western blotting, EGFP concatemers are expressed as fluorescent full-length proteins in eukaryotic cells. As expected, nuclear localization of concatemeric EGFPs decreases with increasing molecular weight. By oligonucleotide ligation this set of EGFP concatemers can be easily fused to NLS motifs. After determination of intracellular localization of EGFP concatemers alone and fused to different NLS motifs we calculated the size of a hypothetic EGFP concatemer showing a defined distribution of EGFP fluorescence between nucleus and cytoplasm (n/c ratio = 2). Clear differences of the size of the hypothetic EGFP concatemer depending on the fused NLS motif were observed. Therefore, we propose to use the size of this hypothetic concatemer as quantitative indicator for comparing strength of different NLS motifs. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Optimized elemental analysis of fluorescence lamp shredder waste.

    Hobohm, Julia; Kuchta, Kerstin; Krüger, Oliver; van Wasen, Sebastian; Adam, Christian

    2016-01-15

    Fluorescence lamps contain considerable amounts of rare earth elements (REE). Several recycling procedures for REE recovery from spent lamps have been established. However, despite their economic importance, the respective recycling is scarce so far, with an REE recovery rate of less than 1%. A reliable analysis of REE and other relevant metals like Yttrium is crucial for a thorough and complete recovery process. This applies both to the solid matter and aqueous phase, since most of the recycling processes include wet-chemical steps. We tested seven different reagent mixtures for microwave-assisted digestion of fluorescent lamp shredder, including hydrofluoric acid, perchloric acid, and hydrogen peroxide. We determined the concentrations of 25 of the most relevant rare earth and other trace elements (Al, P, Ti, V, Cr, Fe, Ni, Cu, Ga, Ge, As, Y, Ag, Cd, Sn, Sb, La, Ce, Eu, Gd, Tb, W, Au, Hg, and Pb) in the respective dilutions. Two independent digestions, one a mixture of perchlorid/nitric/hydrofluoric acid and the other aqua regia, showed the highest concentrations of 23 of these elements, excluding only Sn and Tb. The REE concentrations in the tested lamp shredder sample (stated in g/kg) were 10.2 (Y), 12.1 (La), 7.77 (Ce), 6.91 (Eu), 1.90 (Gd), and 4.11 (Tb). Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Quantitative Brightness Analysis of Fluorescence Intensity Fluctuations in E. Coli.

    Kwang-Ho Hur

    Full Text Available The brightness measured by fluorescence fluctuation spectroscopy specifies the average stoichiometry of a labeled protein in a sample. Here we extended brightness analysis, which has been mainly applied in eukaryotic cells, to prokaryotic cells with E. coli serving as a model system. The small size of the E. coli cell introduces unique challenges for applying brightness analysis that are addressed in this work. Photobleaching leads to a depletion of fluorophores and a reduction of the brightness of protein complexes. In addition, the E. coli cell and the point spread function of the instrument only partially overlap, which influences intensity fluctuations. To address these challenges we developed MSQ analysis, which is based on the mean Q-value of segmented photon count data, and combined it with the analysis of axial scans through the E. coli cell. The MSQ method recovers brightness, concentration, and diffusion time of soluble proteins in E. coli. We applied MSQ to measure the brightness of EGFP in E. coli and compared it to solution measurements. We further used MSQ analysis to determine the oligomeric state of nuclear transport factor 2 labeled with EGFP expressed in E. coli cells. The results obtained demonstrate the feasibility of quantifying the stoichiometry of proteins by brightness analysis in a prokaryotic cell.

  4. Determination of experimental K-shell fluorescence yield for ...

    X-ray; fluorescence yield; cross-section and chemical effects; potassium; cal- ... The X-ray production cross-section in Ti, V, Cr, Mn, Fe, Co, Ni and Cu .... where µinc (cm2 g−1) and µemt (cm2 g−1) are the mass attenuation coefficients at the.

  5. Distribution of diffusion times determined by fluorescence (lifetime) correlation spectroscopy

    Pánek, Jiří; Loukotová, Lenka; Hrubý, Martin; Štěpánek, Petr

    2018-01-01

    Roč. 51, č. 8 (2018), s. 2796-2804 ISSN 0024-9297 R&D Projects: GA MŠk(CZ) LO1507 Institutional support: RVO:61389013 Keywords : polymer solution * fluorescence correlation spectroscopy * diffusion time distribution Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 5.835, year: 2016

  6. Use of X-Ray Fluorescence Spectrometry to Determine Trace ...

    This paper deals with application of X-ray fluorescence spectrometry for the detection of trace elements in graphic. An X-ray spectrometer was constructed and used to carry out measurements on graphite spheres impregnated with different chemical elements. The intensities of the lines of these trace elements, as function of ...

  7. X-ray fluorescent elemental analysis. Ch. 16

    Baryshev, V.; Kulipanov, G.; Skrinsky, A.

    1991-01-01

    X-ray fluorescence analysis (XFA) is used worldwide to define a quantitative content of the elements as well as to visualize the distribution of elements in different regions (element mapping). Utilization of synchrotron radiation (SR) to excite X-ray fluorescence enables the XFA method to be qualitatively improved. This chapter reviews the experimental work in especially the last decade (author). 71 refs.; 24 figs.; 3 tabs

  8. Feasibility of the simultaneous determination of polycyclic aromatic hydrocarbons based on two-dimensional fluorescence correlation spectroscopy

    Yang, Renjie; Dong, Guimei; Sun, Xueshan; Yang, Yanrong; Yu, Yaping; Liu, Haixue; Zhang, Weiyu

    2018-02-01

    A new approach for quantitative determination of polycyclic aromatic hydrocarbons (PAHs) in environment was proposed based on two-dimensional (2D) fluorescence correlation spectroscopy in conjunction with multivariate method. 40 mixture solutions of anthracene and pyrene were prepared in the laboratory. Excitation-emission matrix (EEM) fluorescence spectra of all samples were collected. And 2D fluorescence correlation spectra were calculated under the excitation perturbation. The N-way partial least squares (N-PLS) models were developed based on 2D fluorescence correlation spectra, showing a root mean square error of calibration (RMSEC) of 3.50 μg L- 1 and root mean square error of prediction (RMSEP) of 4.42 μg L- 1 for anthracene and of 3.61 μg L- 1 and 4.29 μg L- 1 for pyrene, respectively. Also, the N-PLS models were developed for quantitative analysis of anthracene and pyrene using EEM fluorescence spectra. The RMSEC and RMSEP were 3.97 μg L- 1 and 4.63 μg L- 1 for anthracene, 4.46 μg L- 1 and 4.52 μg L- 1 for pyrene, respectively. It was found that the N-PLS model using 2D fluorescence correlation spectra could provide better results comparing with EEM fluorescence spectra because of its low RMSEC and RMSEP. The methodology proposed has the potential to be an alternative method for detection of PAHs in environment.

  9. The application of X-ray fluorescence (XRF) method for the determination chemical composition of glass bath raw materials

    Werfel, Z.

    1974-01-01

    The estimation of determination accuracy of glass sand, limestone and dolomite compositions by the means of X-ray fluorescence method has been made. The most important advantage of XRF method application is short time of analysis. The preparation time of sample is not longer than 20 minutes, the analysis of single sample is about 1,5 minutes. The comparison of results of determinations by the means of XRF and complexometric methods have been given. (author)

  10. Determinations of silicon and phosphorus in Pepperbush standard reference material by neutron activation and x-ray fluorescence methods

    Mizumoto, Yoshihiko; Nishio, Hirofumi; Hayashi, Takeshi; Kusakabe, Toshio; Iwata, Shiro.

    1987-01-01

    Silicon and phosphorus contents in Pepperbush standard reference material were determined by neutron activation and X-ray fluorescence methods. In neutron activation analysis, β-ray spectra of 32 P produced by 31 P(n,γ) 32 P reaction on Pepperbush and standard samples were measured by a low background β-ray spectrometer. In X-ray fluorescence analysis, the standard samples were prepared by mixing the Pepperbush powder with silicon dioxide and diammonium hydrogenphosphate. Characteristic X-rays from the samples were analyzed by a wavelength dispersive X-ray fluorescence spectrometer. From the β and X-ray intensities, silicon and phosphorus contents in Pepperbush were determined to be 1840 ± 80 and 1200 ± 50 μg g -1 , respectively. (author)

  11. Novel Spectrofluorimetric Method for the Determination of Perindopril Erbumine Based on Fluorescence Quenching of Rhodamine B.

    Fael, Hanan; Sakur, Amir Al-Haj

    2015-11-01

    A novel, simple and specific spectrofluorimetric method was developed and validated for the determination of perindopril erbumine (PDE). The method is based on the fluorescence quenching of Rhodamine B upon adding perindopril erbumine. The quenched fluorescence was monitored at 578 nm after excitation at 500 nm. The optimization of the reaction conditions such as the solvent, reagent concentration, and reaction time were investigated. Under the optimum conditions, the fluorescence quenching was linear over a concentration range of 1.0-6.0 μg/mL. The proposed method was fully validated and successfully applied to the analysis of perindopril erbumine in pure form and tablets. Statistical comparison of the results obtained by the developed and reference methods revealed no significant differences between the methods compared in terms of accuracy and precision. The method was shown to be highly specific in the presence of indapamide, a diuretic that is commonly combined with perindopril erbumine. The mechanism of rhodamine B quenching was also discussed.

  12. The determination, by x-ray-fluorescence spectrometry, of gold and uranium on resin

    Jacobs, J.J.; Balaes, A.M.E.

    1983-01-01

    The problems encountered in the determination of gold and uranium that are present simultaneously in a sample of resin were considered, and new background positions, as well as correction factors for background lift and partial spectral overlap, were determined for use in the X-ray-fluorescence measurement of these elements. The agreement between the results obtained by the use of the X-ray-fluorescence method and those obtained by atomic-absorption spectrophotometry were found to be satisfactory. The relative standard deviation in the former measurements is 0,005 at a concentration of 1000 p.p.m., and the working range of the calibrations is 15 to 1000 p.p.m. These limits can be extended by further dilution of the sample. The limits of determination are 6 p.p.m. in the briquette prepared from a sample of resin and 18 p.p.m. in the sample when the maximum mass of the sample is 3 g. The procedure is intended primarily for use in the rapid determination of gold and uranium when no analyses for other elements are required. The time taken for the analysis is 2 hours for 10 samples when 6 standards are used. A computer programme that was developed for the processing of the data is appended as part of a laboratory method

  13. Determination of Cerium (IV) Using Rhodamine 6G Fluorescence Quenching

    Zhao, Zh.; Sheng, L.; Su, B.; Tao, C.; Jing, W.

    2017-11-01

    The interaction between rhodamine 6G (Rh6G) and cerium sulfate was studied by the fluorescence quenching method. In a sulfuric acid medium, the interaction of Ce(IV) with Rh6G results in Rh6G fluorescence quenching. The maximum excitation wavelength (λex) and the maximum emission wavelength (λem) are 530 nm and 555 nm, respectively. A good linearity between the relative fl uorescence intensity (ΔF) and Ce(IV) was observed in the range 0.12-1.08 μg/mL. The detection limit was 1.4 × 10-3 μg/mL. The optimum reaction conditions, influencing factors, and effect of coexisting substances were investigated in the experiment. We found that the concentration of Rh6G was 3.2 × 10-6 mol/L, and the fl uorescence intensity was maximum.

  14. Characterization of airborne particulate matter in Santiago, Chile. Part 5: non-destructive determination by x-ray fluorescence

    Poblete, V.H.; Hurtado, O.; Toro, P.

    1995-01-01

    A procedure for non-destructive analysis of airborne particular matter using X ray fluorescence is presented. The elements Fe, Pb and Zn were determined and their concentration compared with the results reported by other techniques. The homogeneity of the distribution of Fe in the samples was investigated. (author). 4 refs, 5 figs

  15. Determination of experimental K-shell fluorescence yield for ...

    calcium compounds using a Si(Li) X-ray detector system (FWHM=5.96 keV at 160 eV). The samples were excited by 5.96 keV photons produced by a 55Fe radioisotope source. The experimental values are systematically lower than the theoretical values. Keywords. X-ray; fluorescence yield; cross-section and chemical ...

  16. A single-chip computer analysis system for liquid fluorescence

    Zhang Yongming; Wu Ruisheng; Li Bin

    1998-01-01

    The single-chip computer analysis system for liquid fluorescence is an intelligent analytic instrument, which is based on the principle that the liquid containing hydrocarbons can give out several characteristic fluorescences when irradiated by strong light. Besides a single-chip computer, the system makes use of the keyboard and the calculation and printing functions of a CASIO printing calculator. It combines optics, mechanism and electronics into one, and is small, light and practical, so it can be used for surface water sample analysis in oil field and impurity analysis of other materials

  17. Applications of optical fiber to remote laser fluorescence analysis

    Kim, Cheol Jung; Shin, Jang Soo; Lee, Sang Mock; Kim, Jeong Moog; Kim, Duk Heon; Hong, Seok Kyung

    1991-12-01

    Fluorescence analysis using time-resolved laser fluorimetry has been used for trace uranium analysis because this method shows high sensitivity and low detection limit and is less matrix dependent than any other fluorimetric measurement. By this time, the uranium analyses in the solution of reprocessing process or high radioactive area have been primarily analyzed by sampling of the solution, but recently, a study on a remote uranium fluorescence analysis using optical fiber has been setting out based on the development of an optical fiber with radiation resistivity and of an advanced laser excitation source. Laser fluorimetry developed by our laboratory for trace uranium analyses in uranium handling process or in urine samples of workers in a nuclear facility has been used in our institute since 1988. A development of the system for remote control of uranium fluorescence analysis will be expected to contribute to an on-line uranium concentration monitoring in the cooling water of reconversion stream. In this report, we summarize the information related to fluorescence analyses and remote fluorescence monitoring methods established by foreign countries and our laboratory. We also present a future research direction for remote on-line monitoring of uranium in conversion or reconversion process. (Author)

  18. Research Note: Energy dispersive x-ray fluorescence analysis ...

    Energy Dispersive X-Ray fluorescence (EDXRF) technique for the analysis of geological, biological and environmental samples is described. The technique has been applied in the analysis of 10 (geological, biological, environmental) standard reference materials. The accuracy and precision of the technique were attested ...

  19. Multielement characterization of atmospheric pollutants by x-ray fluorescence analysis and instrumental neutron activation analysis

    Rancitelli, L.A.; Tanner, T.M.

    1976-01-01

    The simultaneous measurement of a wide spectrum of elements in aerosols collected on air filters and in rainwater can yield information on the origin, transport, and removal of atmospheric pollutants. In order to determine the elemental content of these aerosols, a pair of highly sensitive, precise and complementing instrumental techniques, x-ray fluorescence and neutron activation analysis, have been developed and employed. Data are presented on the results of combined x-ray fluorescence and activation analysis of aerosols collected in a number of urban areas of the USA and from the 80th median sampling network in March 1972. From a comparison of these ratios in granite and diabase with those of filters placed in urban areas, it is evident that Zn, Se, Sb, Hg, and Pb levels have been increased by as much as several orders of magnitude. Al, Co, La, Fe, Eu, Sm, Tb, Ta, Hf, and Th appear to exist at levels compatible with an earth's crust origin

  20. Determination of paraquat in water samples using a sensitive fluorescent probe titration method.

    Yao, Feihu; Liu, Hailong; Wang, Guangquan; Du, Liming; Yin, Xiaofen; Fu, Yunlong

    2013-06-01

    Paraquat (PQ), a nonselective herbicide, is non-fluorescent in aqueous solutions. Thus, its determination through direct fluorescent methods is not feasible. The supramolecular inclusion interaction of PQ with cucurbit[7]uril was studied by a fluorescent probe titration method. Significant quenching of the fluorescence intensity of the cucurbit[7]uril-coptisine fluorescent probe was observed with the addition of PQ. A new fluorescent probe titration method with high selectivity and sensitivity at the ng/mL level was developed to determine PQ in aqueous solutions with good precision and accuracy based on the significant quenching of the supramolecular complex fluorescence intensity. The proposed method was successfully used in the determination of PQ in lake water, tap water, well water, and ditch water in an agricultural area, with recoveries of 96.73% to 105.77%. The fluorescence quenching values (deltaF) showed a good linear relationship with PQ concentrations from 1.0 x 10(-8) to 1.2 x 10(-5) mol/L with a detection limit of 3.35 x 10(-9) mol/L. In addition, the interaction models of the supramolecular complexes formed between the host and the guest were established using theoretical calculations. The interaction mechanism between the cucurbit[7]uril and PQ was confirmed by 1H NMR spectroscopy.

  1. Sample preparation of waste water to determine metallic contaminants by X-ray fluorescence spectroscopy

    Gonzalez Olivos, Javier.

    1987-01-01

    Trace X-ray fluorescence spectroscopy analysis in liquid samples is preceded by sample preparation, which usually consists in the precipitation of the metallic ions and concentration over a thin cellulose filter. The samples preparation of waste water by this method is not efficient, due to the great amount of organic and insoluble matter that they contain. The purpose of this work was to determine the optimal value of pH in order to adsorbe all the insoluble matter contained in a waste water sample in the activated charcoal, so that the metallic ions could be precipitated and concentrated on a thin filter and determinated by X-ray fluorescence spectroscopy. A survey about the adsorption of some ions in activated charcoal in function of the pH was made for the following: Cr 3+ , Fe 3+ , Ni 2+ , Cu 2+ , Zn 2+ , Se 2+ , Hg 2+ , and Pb 2+ . It was observed that at pH 0, the ions are not adsorbed, but Cu 2+ and Zn 2+ are adsorbed in small amount; at pH 14, the ions are adsorbed, excluding Se, which is not adsorbed at any value of pH. If a waste water sample is treated at pH 0 with activated charcoal to adsorbe the organic and insoluble matter, most of the metallic ions are not adsorbed by the activated charcoal and could be precipitated with APDC (ammonium 1-pirrolidine dithio carbamate salt) and concentrated on a thin filter. The analysis of the metallic ions contained on the filter and those adsorbed in the activated charcoal by X-ray fluorescence spectroscopy, gave the total amount of the ions in the sample. (author)

  2. CHLOROPHYLL a FLUORESCENCE ANALYSIS IN FORESTS

    M. Pollastrini

    2016-03-01

    Full Text Available A European-wide assessment of chlorophyll a fluorescence (ChlF, prompt fluorescence on dark-adapted samples parameters in forest ecosystems was carried out in the years 2012-2013, within the 7FP FunDivEUROPE project. A total of 1596 trees growing in 209 stands distributed in six countries, from Mediterranean to boreal sites, were sampled. This paper shows the applicability of the ChlF in forest ecology surveys, the protocols adopted for leaf sampling and ChlF measurements, the variability of the ChlF parameters within and between trees, their dependence to environmental factors and the relationships with other functional leaf traits. The most relevant findings were as follows: (i The least variable ChlF parameter within and between the trees was the maximum quantum yield of primary photochemistry (FV/FM, whereas the performance indices (PIABS and PITOT showed the highest variability; (ii for a given tree, the ChlF parameters measured at two heights of the crown (top and bottom leaves were correlated and, in coniferous species, the ChlF parameters were correlated between different needle age classes (from the current year and previous year; (iii the ChlF parameters showed a geographical pattern, and the photochemical performance of the forest trees was higher in central Europe than in the edge sites (northernmost and southernmost; and (iv ChlF parameters showed different sensitivity to specific environmental factors: FV/FM increased with the increase of the leaf area index of stands and soil fertility; ΔVIP was reduced under high temperature and drought. The photochemical responses of forest tree species, analyzed with ChlF parameters, were influenced by the ecology of the trees (i.e. their functional groups, continental distribution, successional status, etc., tree species’ richness and composition of the stands. Our results support the applicability and usefulness of the ChlF in forest monitoring investigations on a large spatial scale and

  3. MCNP calculation for calibration curve of X-ray fluorescence analysis

    Tan Chunming; Wu Zhifang; Guo Xiaojing; Xing Guilai; Wang Zhentao

    2011-01-01

    Due to the compositional variation of the sample, linear relationship between the element concentration and fluorescent intensity will not be well maintained in most X-ray fluorescence analysis. To overcome this, we use MCNP program to simulate fluorescent intensity of Fe (0∼100% concentration range) within binary mixture of Cr and O which represent typical strong absorption and weak absorption conditions respectively. The theoretic calculation shows that the relationship can be described as a curve determined by parameter p and value of p can be obtained with given absorption coefficient of substrate elements and element under detection. MCNP simulation results are consistent with theoretic calculation. Our research reveals that MCNP program can calculate the Calibration Curve of X-ray fluorescence very well. (authors)

  4. 3-D Image Analysis of Fluorescent Drug Binding

    M. Raquel Miquel

    2005-01-01

    Full Text Available Fluorescent ligands provide the means of studying receptors in whole tissues using confocal laser scanning microscopy and have advantages over antibody- or non-fluorescence-based method. Confocal microscopy provides large volumes of images to be measured. Histogram analysis of 3-D image volumes is proposed as a method of graphically displaying large amounts of volumetric image data to be quickly analyzed and compared. The fluorescent ligand BODIPY FL-prazosin (QAPB was used in mouse aorta. Histogram analysis reports the amount of ligand-receptor binding under different conditions and the technique is sensitive enough to detect changes in receptor availability after antagonist incubation or genetic manipulations. QAPB binding was concentration dependent, causing concentration-related rightward shifts in the histogram. In the presence of 10 μM phenoxybenzamine (blocking agent, the QAPB (50 nM histogram overlaps the autofluorescence curve. The histogram obtained for the 1D knockout aorta lay to the left of that of control and 1B knockout aorta, indicating a reduction in 1D receptors. We have shown, for the first time, that it is possible to graphically display binding of a fluorescent drug to a biological tissue. Although our application is specific to adrenergic receptors, the general method could be applied to any volumetric, fluorescence-image-based assay.

  5. Evaluation of methods for mathematical corrections in the determination of niobium and zirconium contents in U-Nb and U-Zr alloys by X-ray fluorescence analysis

    Salvador, V.L.R.; Sato, I.M.; Lordello, A.R.

    1985-01-01

    Methods for the determination of niobium and zirconium in U-Nb and U-Zr alloys with the X-ray fluorescence technique are described. The NbK sub(Ab) line, although not under the overlapping effect of the uranium lines as the NbK sub(β) line, although not under the overlapping effect of the uranium lines as the NbK sub(α) is, presents a more intensive absorption effect than this last one; on the other hand the ZrK sub(α) and ZrK sub(β) lines are under the overlapping effect of the uranium spectrum. Such interferences are mathematically corrected by means of relations between the intensities of the lines for the elements and those for the uranium. The technique for the preparation of the samples is the double layer pressed pellet. From the different corrections the best method has showed a precision of 5%. (Author) [pt

  6. Determination of low concentrations of thorium in granites using X-ray fluorescence technique

    Shigematsu, H.M.; Sato, I.M.; Iyer, S.S.

    1981-03-01

    An analytical method for the accurate determination of low concentrations of thorium in rocks using X-ray fluorescence technique, was developed. A tungsten tube was utilized for the production of X-rays. The samples were prepared in the form of double layer pressed pellets using boric acid as a binding agent. The concentration of thorium was determined by measuring the intensity of the characteristic first order Th L α line. The calibration was carried out with USGS rock standards AGV-1, GSP-1 and G-2. Seven granite rocks samples from Granite Mountains of Wyoming, USA, supplied by Dr. Stuckless. Also were analysed. The results obtained were compared with values obtained in others laboratories using different analytical methods. The analyses show that the thorium is concentrated in accessory minerals and presented a non-uniform distribution, making sampling an important factor in the analysis of thorium. A discussion of the precision and accuracy of the method is presented. (Author) [pt

  7. Analysis of eight argonne premium coal samples by X-ray fluorescence spectrometry

    Evans, J.R.; Sellers, G.A.; Johnson, R.G.; Vivit, D.V.; Kent, J.

    1990-01-01

    X-ray fluorescence spectrometric methods were used in the analysis of eight Argonne Premium Coal Samples. Trace elements (Cr, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, La, and Ce) in coal ash were determined by energy-dispersive X-ray fluorescence spectrometry; major elements (Na, Mg, Al, Si, P, S, K, Ca, Ti, Mn, and Fe) in coal ash and trace elements (Cl and P) in whole coal were determined by wavelength-dispersive X-ray fluorescence spectrometry. The results of this study will be used in a geochemical database compiled for these materials from various analytical techniques. The experimental XRF methods and procedures used to determine these major and trace elements are described.

  8. Renal function measured by X-ray fluorescence analysis

    Boijsen, M.; Jacobsson, L.; Tylen, U.; Sahlgrenska Sjukhuset, Goeteborg

    1987-01-01

    In twenty-six patients injected with metrizoate during urography, plasma was analyzed for iodine concentration using X-ray fluorescence analysis, and total plasma clearance of contrast medium was calculated. Total plasma clearance of 51 Cr-EDTA was also determined, but not simultaneously, in order to find out if the urographic procedure would influence the kidneys to such an extent that the contrast medium clearance value would differ much from the 51 Cr-EDTA clearance value. The errors in the method were assessed and the total error of the contrast medium clearance determination was calculated. When comparing 51 Cr-EDTA and metrizoate clearance a correlation of 0.94 and a mean ratio of 1.046 (SD 0.138) was found. The assessable errors cannot fully explain the standard deviation, which might indicate a transient change in kidney function related to elements of the urographic procedure such as laxation with possible dehydration and/or the contrast medium dose. (orig.)

  9. Determination of the carmine content based on spectrum fluorescence spectral and PSO-SVM

    Wang, Shu-tao; Peng, Tao; Cheng, Qi; Wang, Gui-chuan; Kong, De-ming; Wang, Yu-tian

    2018-03-01

    Carmine is a widely used food pigment in various food and beverage additives. Excessive consumption of synthetic pigment shall do harm to body seriously. The food is generally associated with a variety of colors. Under the simulation context of various food pigments' coexistence, we adopted the technology of fluorescence spectroscopy, together with the PSO-SVM algorithm, so that to establish a method for the determination of carmine content in mixed solution. After analyzing the prediction results of PSO-SVM, we collected a bunch of data: the carmine average recovery rate was 100.84%, the root mean square error of prediction (RMSEP) for 1.03e-04, 0.999 for the correlation coefficient between the model output and the real value of the forecast. Compared with the prediction results of reverse transmission, the correlation coefficient of PSO-SVM was 2.7% higher, the average recovery rate for 0.6%, and the root mean square error was nearly one order of magnitude lower. According to the analysis results, it can effectively avoid the interference caused by pigment with the combination of the fluorescence spectrum technique and PSO-SVM, accurately determining the content of carmine in mixed solution with an effect better than that of BP.

  10. X-ray fluorescence analysis of thulium oxide/oxalate for rare earth impurities

    Chandola, L.C.; Khanna, P.P.

    1986-01-01

    An X-ray fluorescence spectrometric method for the analysis of thulium oxide is described. For the analysis, the sample in oxalate form is mixed with boric acid binding material and pressed into a pellet over a supporting pellet of boric acid. A wavelength dispersive Philips PW 1220 X-ray fluorescence spectrometer is used for the experiments; the minimum determination limits are 0.002per cent for Ho, Lu and Y, 0.005per cent for Dy and Er and 0.01per cent for Yb. Calculations for theoretical minimum detection limits and percent standard deviation at each concentration of the standard are carried out. (author)

  11. X-ray fluorescence analysis of lutetium oxide/oxalate for rare earth impurities

    Chandola, L.C.; Khanna, P.P.

    1985-01-01

    An X-ray fluorescence spectrometric method for the analysis of lutetium oxide is described. The sample in the oxalate form is mixed with boric acid binding material and pressed into a pellet over supporting pellet of boric acid. A Philips PW 1220 wavelength dispersive semiautomatic X-ray fluorescence spectrometer is used for the analysis. The minimum determination limit is 0.002 percent for Y, Er and Yb and 0.005 percent for Tm. Calculations for theoretical minimum detection limits and percent standard deviations at each concentration of the standard are carried out. (author)

  12. X-ray fluorescence analysis and optical emission spectrometry of an roman mirror from Tomis, Romania

    Belc, M.; Bogoi, M.; Ionescu, D.; Guita, D.; Caiteanu, S.; Caiteanu, D.

    2000-01-01

    The miscellaneous population of Roman Empire, their diverse cultural tradition, their ability to assimilate the roman civilization spirits, had determined a permanent reassessment superimposed upon the roman contribution. Analysis was undertaken using optical emission spectrometry and non-destructive X-ray fluorescence. X-ray fluorescence analysis is a well-established method and is often used in archaeometry and other work dealing with valuable objects pertaining to the history of art and civilization. Roman mirror analysed has been found not to be made of speculum (a high tin bronze). (authors)

  13. X-ray fluorescence spectrometry applied to soil analysis

    Salvador, Vera Lucia Ribeiro; Sato, Ivone Mulako; Scapin Junior, Wilson Santo; Scapin, Marcos Antonio; Imakima, Kengo

    1997-01-01

    This paper studies the X-ray fluorescence spectrometry applied to the soil analysis. A comparative study of the WD-XRFS and ED-XRFS techniques was carried out by using the following soil samples: SL-1, SOIL-7 and marine sediment SD-M-2/TM, from IAEA, and clay, JG-1a from Geological Survey of Japan (GSJ)

  14. Mercury mass measurement in fluorescent lamps via neutron activation analysis

    Viererbl, L.; Vinš, M.; Lahodová, Z.; Fuksa, A.; Kučera, Jan; Koleska, M.; Voljanskij, A.

    2015-01-01

    Roč. 116, NOV (2015), s. 56-59 ISSN 0969-806X R&D Projects: GA TA ČR TA01010237; GA MŠk LM2011019 Institutional support: RVO:61389005 Keywords : fluorescent lamp * mercury measurement * neutron activation analysis * research reactor Subject RIV: BG - Nuclear , Atomic and Molecular Physics, Colliders Impact factor: 1.207, year: 2015

  15. A portable tube exciting X-ray fluorescence analysis system

    Yang Qiang; Lai Wanchang; Ge Liangquan

    2009-01-01

    Article introduced a portable tube exciting X-ray fluorescence analysis system which is based on arm architecture. Also, we designed Tube control circuit and finished preliminary application. The energy and the intensity of the photon can be adjusted continuously by using the tube. Experiments show that high excitation efficiency obtained by setting the appropriate parameters of the tube for the various elements. (authors)

  16. Multielement methods of atomic fluorescence analysis of enviromental samples

    Rigin, V.I.

    1985-01-01

    A multielement method of atomic fluorescence analysis of environmental samples based on sample decomposition by autoclave fluorination and gas-phase atomization of volatile compounds in inductive araon plasma using a nondispersive polychromator is suggested. Detection limits of some elements (Be, Sr, Cd, V, Mo, Te, Ru etc.) for different sample forms introduced in to an analyzer are given

  17. Determination of solid surface composition by the X-ray fluorescence method under total external reflection with angular scanning

    Krasnolutskij, V.P.

    2000-01-01

    Possibilities of determination of composition of surface layers by X-ray fluorescence analysis under total reflection of incident radiation with angular scanning of a target are investigated. For the case of the GaAs target it is shown that the sensibility of this method is sufficient for a control of element composition in layer of thickness 1 nm. A simple method for solution of inverse task of analysis of a two component medium is considered [ru

  18. Quantitative analysis with energy dispersive X-ray fluorescence analyser

    Kataria, S.K.; Kapoor, S.S.; Lal, M.; Rao, B.V.N.

    1977-01-01

    Quantitative analysis of samples using radioisotope excited energy dispersive x-ray fluorescence system is described. The complete set-up is built around a locally made Si(Li) detector x-ray spectrometer with an energy resolution of 220 eV at 5.94 KeV. The photopeaks observed in the x-ray fluorescence spectra are fitted with a Gaussian function and the intensities of the characteristic x-ray lines are extracted, which in turn are used for calculating the elemental concentrations. The results for a few typical cases are presented. (author)

  19. Method and device for X-ray fluorescence analysis

    Jagoutz, E.; Palme, C.

    1978-01-01

    In the x-ray fluorescence analyzer the useful signal can be completely separated from the spurious signals, and especially the pulse can be determined. For this purpose the output of the radiation detector is connected with a multichannel pulse height discriminator. The measured signal determined in the pulse heigth discriminator may be indicated by a visual display or processed by a computer (coincidence circuits). (DG) [de

  20. Determinations of elements in pepperbush standard reference material by neutron activation and X-ray fluorescence analyses

    Mizumoto, Yoshihiko; Okada, Takayuki; Tatsumi, Toshiya; Kusakabe, Toshio; Katsurayama, Kousuke; Iwata, Shiro.

    1988-01-01

    Elemental contents in Pepperbush standard reference material have been determined by neutron activation and X-ray fluorescence analyses. The standard samples of orchard leaves, tomato leaves, pine needles and Kale are used for the experiment. In the neutron activation analysis, gamma-ray spectra of nuclei produced by (n,γ) reaction on Pepperbush and standard samples are measured with Ge detectors. In the X-ray fluorescence analysis, the samples are excited with X-rays from X-ray tube with rhodium anode, and the characteristic X-rays from samples are measured with a proportional counter or NaI(Tl) detector. From the gamma- and X-ray intensities, the elemental contents in Pepperbush are determined. As a result, the contents of seventeen elements, such as sodium, calcium, iron, etc., in Pepperbush are determined. (author)

  1. Characterization of antibody-chelator conjugates: Determination of chelator content by terbium fluorescence titration

    Brandt, K.D.; Schnobrich, K.E.; Johnson, D.K. (Abbott Laboratories, Department 90M, Abbott Park, IL (United States))

    1991-01-01

    Fluorescence titrations were performed by adding varying mole ratios of terbium(III) to antibody conjugates formed by benzyl isothiocyanate derivatives of three different polyaminopolycarboxylate chelators (NTA, EDTA, and DTPA) and the results compared to values for average chelator content obtained by cobalt-57 binding assays. For two different murine monoclonal antibodies, the average chelator content obtained by terbium fluorescence titration correlated closely with that measured by the cobalt-57 binding assay. It is concluded that lanthanide fluorescence titrations provide a useful alternative to radiometal binding assays for the determination of chelator content in protein-chelator conjugates.

  2. Characterization of antibody-chelator conjugates: Determination of chelator content by terbium fluorescence titration

    Brandt, K.D.; Schnobrich, K.E.; Johnson, D.K.

    1991-01-01

    Fluorescence titrations were performed by adding varying mole ratios of terbium(III) to antibody conjugates formed by benzyl isothiocyanate derivatives of three different polyaminopolycarboxylate chelators (NTA, EDTA, and DTPA) and the results compared to values for average chelator content obtained by cobalt-57 binding assays. For two different murine monoclonal antibodies, the average chelator content obtained by terbium fluorescence titration correlated closely with that measured by the cobalt-57 binding assay. It is concluded that lanthanide fluorescence titrations provide a useful alternative to radiometal binding assays for the determination of chelator content in protein-chelator conjugates

  3. Sensitivity of in vivo X-ray fluorescence determination of skeletal lead stores

    Sokas, R.K.; Besarab, A.; McDiarmid, M.A.; Shapiro, I.M.; Bloch, P.

    1990-01-01

    Eighteen patients with known past occupational lead exposure underwent parenteral diagnostic chelation with ethylenediaminetetraacetic acid and x-ray fluorescent determination of in vivo skeletal lead stores at the distal styloid process of the ulna and at the temporal base bone using a cobalt 57 source and measuring lead Ka x-rays. X-ray fluorescent lead measurements in both locations correlated with results of diagnostic chelation. Using a post-chelation urinary excretion of greater than 600 micrograms lead/24 h as the definition of high-lead stores, sensitivity of x-ray fluorescence at the wrist and temple was 56% and 39%, respectively

  4. Laser fluorescence determination of radioactive waste cotton fabric in the exploration of uranium content

    Wang Jiangong

    2010-01-01

    In order to meet the dosage test the operational needs of the laser fluorescence determination of trace radioactive waste cotton fabric uranium research and exploration, to determine the sample ashing time, measured dosage of acidity and digestion and other technical parameters, gives the laser fluorescence determination of radioactive abandoned cotton fabric of trace uranium method. Method of high sensitivity, strong anti-interference, the detection limit of 0.025μg/g(Burning down dregs), relative standard deviation was 3.96%, the mean recovery 93.3%-103% for masks, gloves and other radioactive waste to the determination of trace uranium. (authors)

  5. Fluorescent turn-on determination of the activity of peptidases using peptide templated gold nanoclusters

    Luo, Junjun; Wang, Liqiang; Zeng, Ke; Shen, Congcong; Qian, Pin; Yang, Minghui; Rasooly, Avraham; Qu, Fengli

    2016-01-01

    The fluorescence intensity of gold nanoclusters (AuNCs) is inversely related to the length of a peptide immobilized on its surface. This finding has been exploited to design a turn-on fluorescent method for the determination of the activity of peptidase. The β-site amyloid precursor protein-cleaving enzyme 1 (BACE1) was chosen as a model peptidase. BACE1 cleaves the peptide substrates on AuNCs, and the fluorescence intensity of the AuNCs (at exCitation/emission wavelengths of 320/405 nm) carrying the rest of the cleaved peptide is significantly higher than that of the AuNCs with uncleaved peptide. Transmission electron microscopy revealed a decrease in the size of the AuNCs which is assumed cause fluorescence enhancement. The assay was applied to the determination of BACE1 activity in spiked cell lysates, and recoveries were between 96.9 and 104.0 %. (author)

  6. Fluorescence method for the determination of carcinogenic N-nitrosamines using N-(8-methoxy-5-quinolinesulfonyl)-aziridine

    Gracheva, I.N.; Kovel'man, I.R.; Pimenova, V.V.; Tochilkin, A.I.; Zhukova, G.F.

    1986-01-01

    The determination of carcinogenic N-nitrosamines (NA) in the environment and particularly in food products is, according to the authors, extremely important. The objective of the present work is the development of an easily accessible and highly sensitive method for the determination of NA. NA, isolated from food products, are denitrosated to their corresponding amines, which are then determined in the form of fluorescent derivatives by reaction with N-(8-methoxy-5-quinolinesulfonyl) aziridine. The validity of the results of NA analysis from food product was confirmed by gas-liquid chromatography using a thermoluminescent detector TEA-502. The limit of detection is 1x10 -10 mole of N-nitrosamine. The possibility of separating and determining the new fluorescent derivatives III(a-f) on silufol plates, which are easily obtained and widely used in analytical practice, was examined

  7. Determination of aristolochic acids by high-performance liquid chromatography with fluorescence detection.

    Wang, Yinan; Chan, Wan

    2014-06-25

    Nephrotoxic and carcinogenic aristolochic acids (AAs) are naturally occurring nitrophenanthrene carboxylic acids in the herbal genus Aristolochia. The misuse of AA-containing herbs in preparing slimming drugs has caused hundred of cases of kidney disease in Belgium women in a slimming regime in the early 1990s. Accumulating evidence also suggested that prolong dietary intake of AA-contaminated food is one of the major causes to the Balkan endemic nephropathy that was first observed in the late 1950s. Therefore, analytical methods of high sensitivity are extremely important for safeguarding human exposure to AA-containing herbal medicines, herbal remedies, and food composites. In this paper, we describe the development of a new high-performance liquid chromatography coupled fluorescence detector (HPLC-FLD) method for the sensitive determination of AAs. The method makes use of a novel cysteine-induced denitration reaction that "turns on" the fluorescence of AAs for fluorometric detections. Our results showed that the combination of cysteine-induced denitration and HPLC-FLD analysis allows for sensitive quantification of AA-I and AA-II at detection limits of 27.1 and 25.4 ng/g, respectively. The method was validated and has been successfully applied in quantifying AAs in Chinese herbal medicines.

  8. Determination of ultratrace concentrations of uranium and thorium in natural waters by x-ray fluorescence

    Stewart, J.H. Jr.; Brooksbank, R.D.

    1981-01-01

    An x-ray fluorescence method for the simultaneous determination of uranium and thorium at the less than 1 ppM level in natural waters is described. Uranium and thorium are coprecipitated with an internal standard, yttrium, and incorporated into an iron-aluminum hydroxide carrier. The hydroxide precipitate is filtered, and the filter disk is analyzed by the energy-dispersive x-ray fluorescence technique. Matrix interferences caused by the presence of unpredictable anions and cations are compensated for by the internal standard. The U/Y and Th/Y ratios are linear over the 5- to 100-μg range of interest, and the detection limit of each element on the filter disk is 2 μg (3 sigma). Relative standard deviation was 17% at the 15-μg and 4% at the 100-μg level for thorium and 11% at the 11-μg and 2% at the 100-μg level for uranium. Analysis of spiked solutions showed a recovery of 19.6 +- 0.3 μg for uranium and 19.8 +- 0.3 μg for thorium at the 20-μg level, and the normal lower reporting limit is 5 μg. Fifty disks can be routinely measured during a normal working day

  9. A BIOSENSOR USING COUPLED PLASMON WAVEGUIDE RESONANCE COMBINED WITH HYPERSPECTRAL FLUORESCENCE ANALYSIS

    CHAN DU

    2014-01-01

    Full Text Available We developed a biosensor that is capable for simultaneous surface plasmon resonance (SPR sensing and hyperspectral fluorescence analysis in this paper. A symmetrical metal-dielectric slab scheme is employed for the excitation of coupled plasmon waveguide resonance (CPWR in the present work. Resonance between surface plasmon mode and the guided waveguide mode generates narrower full width half-maximum of the reflective curves which leads to increased precision for the determination of refractive index over conventional SPR sensors. In addition, CPWR also offers longer surface propagation depths and higher surface electric field strengths that enable the excitation of fluorescence with hyperspectral technique to maintain an appreciable signal-to-noise ratio. The refractive index information obtained from SPR sensing and the chemical properties obtained through hyperspectral fluorescence analysis confirm each other to exclude false-positive or false-negative cases. The sensor provides a comprehensive understanding of the biological events on the sensor chips.

  10. On-line analysis of algae in water by discrete three-dimensional fluorescence spectroscopy.

    Zhao, Nanjing; Zhang, Xiaoling; Yin, Gaofang; Yang, Ruifang; Hu, Li; Chen, Shuang; Liu, Jianguo; Liu, Wenqing

    2018-03-19

    In view of the problem of the on-line measurement of algae classification, a method of algae classification and concentration determination based on the discrete three-dimensional fluorescence spectra was studied in this work. The discrete three-dimensional fluorescence spectra of twelve common species of algae belonging to five categories were analyzed, the discrete three-dimensional standard spectra of five categories were built, and the recognition, classification and concentration prediction of algae categories were realized by the discrete three-dimensional fluorescence spectra coupled with non-negative weighted least squares linear regression analysis. The results show that similarities between discrete three-dimensional standard spectra of different categories were reduced and the accuracies of recognition, classification and concentration prediction of the algae categories were significantly improved. By comparing with that of the chlorophyll a fluorescence excitation spectra method, the recognition accuracy rate in pure samples by discrete three-dimensional fluorescence spectra is improved 1.38%, and the recovery rate and classification accuracy in pure diatom samples 34.1% and 46.8%, respectively; the recognition accuracy rate of mixed samples by discrete-three dimensional fluorescence spectra is enhanced by 26.1%, the recovery rate of mixed samples with Chlorophyta 37.8%, and the classification accuracy of mixed samples with diatoms 54.6%.

  11. Determining sulfur in metallurgical coke by the X-ray fluorescent method

    Sofilic, T.; Kesic-Racan, M.; Sindler, M.; Sokolean, D.

    1979-01-01

    A method is described of X-ray fluorescent analysis for current determination of sulfur in the concentration range of 0.5-1.16% in metallurgical coke. To do this, the analyzed material (coke) is ground to a particle size of 200 mu and mixed in a 1:1 ratio with an organic binder (soluble starch). The mixture is briquetted in meshes of a certain size under a pressure of 25 tons/cm/sub 2/. The tablets obtained are analyzed in a Phillips spectrometer with a Cr anticathode. The presence is noted of a linear dependence between the S content and the instrument reading; the correlation factor is 0.91; the mean detection error, 0.0596.

  12. SAVLOC, computer program for automatic control and analysis of X-ray fluorescence experiments

    Leonard, R. F.

    1977-01-01

    A program for a PDP-15 computer is presented which provides for control and analysis of trace element determinations by using X-ray fluorescence. The program simultaneously handles data accumulation for one sample and analysis of data from previous samples. Data accumulation consists of sample changing, timing, and data storage. Analysis requires the locating of peaks in X-ray spectra, determination of intensities of peaks, identification of origins of peaks, and determination of a real density of the element responsible for each peak. The program may be run in either a manual (supervised) mode or an automatic (unsupervised) mode.

  13. Development and validation of a solid-phase extraction method coupled to liquid chromatography with fluorescence detection for the determination of fluoroquinolone residues in powdered infant formulae. Application to the analysis of samples from the Spanish and Latin American market.

    Rodriguez, E; Moreno-Bondi, M C; Marazuela, M D

    2008-10-31

    This paper describes a new method for the effective extraction, clean-up and chromatographic analysis of residues of four fluoroquinolones (ciprofloxacin, enrofloxacin, danofloxacin and sarafloxacin) in powdered infant formulae and follow-on preparations. Samples were reconstituted following the manufacturer's recommendations and treated with trichloroacetic acid in methanol 10% (w/v) for deproteinization. Two solid-phase extraction cartridges have been evaluated for sample clean-up and preconcentration, Strata Screen A and Strata X and the later provided the best recoveries for all the analytes tested. Chromatographic analysis has been carried out using a polar endcapped column (AQUA C(18)) and fluorescence detection, with lomefloxacin (LOME) as internal standard. Method validation has been performed according to European Commission Decision 2002/657/EC criteria, in terms of linearity, recovery, precision, specificity, decision limit (CC(alpha)) and detection capability (CC(beta)). Typical recoveries ranged between 70 and 110% at levels below and above the maximum residue limits of the target analytes in bovine milk, with an excellent intralab reproducibility (RSDsmarket, using LC-MS/MS as confirmatory technique.

  14. [Simultaneous determination of multiple elements in airborne particulate samples by X-ray fluorescence spectrometry].

    Takada, T; Hitosugi, M; Kadowaki, T; Kudo, M

    1983-07-01

    An energy dispersive X-ray fluorescence spectrometer (EDX) has been applied to determine multielements in the workplace air. The standards for X-ray fluorescence analysis were prepared by the chelate precipitation method on polyvinyl chloride (PVC) membrane filter. And, the specimens were prepared to deposit various metal compounds of different chemical forms by the suspension method on PVC membrane filter, and they were determined with EDX and atomic absorption spectrometer (AAS). The results obtained were as follows. Though there is a difference by each element, an amount less than 3 microgram/cm2 per unit area makes it possible to undergo multielement analysis, that is, is has no influence on fine particle effect (particle size; under 5 microns). Then, effects of the X-ray intensity by different chemical forms are negligible. At the presence the neighboring element and other elements this technique showed greater precision by carrying out on corrective treatment, etc. The coefficient of variation of this technique was in the range of 2.5-6.5% at DDTC-Cu of 0.5-5.0 micrograms/cm2, with the limit of detection for As : 0.002 microgram/cm2, Zn : 0.003 microgram/cm2, Pb : 0.003 microgram/cm2, Cu : 0.004 microgram/cm2, Ni : 0.003 microgram/cm2, Fe : 0.005 microgram/cm2, Mn : 0.008 microgram/cm2, Cr : 0.013 microgram/cm2, respectively. Aerosols collected at the workplace were analyzed with EDX and AAS, and the obtained results showed good agreement with such regression line as y = 1.04 chi + 0.04, the coefficient of correlation being r = 0.995. From these results, this technique was found to be a very excellent method for monitoring of multielements in the workplace air.

  15. Application of synchrotron radiation to x-ray fluorescence analysis of trace elements

    Gordon, B.M.; Jones, K.W.; Hanson, A.L.

    1986-08-01

    The development of synchrotron radiation x-ray sources has provided the means to greatly extend the capabilities of x-ray fluorescence analysis for determinations of trace element concentrations. A brief description of synchrotron radiation properties provides a background for a discussion of the improved detection limits compared to existing x-ray fluorescence techniques. Calculated detection limits for x-ray microprobes with micrometer spatial resolutions are described and compared with experimental results beginning to appear from a number of laboratories. The current activities and future plans for a dedicated x-ray microprobe beam line at the National Synchrotron Light Source (NSLS) of Brookhaven National Laboratory are presented

  16. Simultaneous determination of actinides by x-ray fluorescence spectrometry

    Cohen, V.H.

    1990-01-01

    The x-ray spectrometric simultaneous determination of uranium and plutonium in simulated Purex Process solutions is described. The method is accomplished by intensity measurements of the L α sub(1) lines. The thin film technique for sample preparation and thorium as an internal standard had been used. An evaporation technique had been also tested for low concentration uranium solutions. In the measurement range 0,05 - 130 U g/L, 0,5 - 20 Pu g/L linear calibration curves were effected. The standard deviation in the concentration range 10 to 130 g/L was 3,5%, 4% in the 1 to 10 g/L and 13% in 0,05 to 1 g/L for uranium determination and 4% for plutonium determination in the range of 1 to 20 g/L. The sensitivity of the method was about 3,62 μg to U and 3,95 μg to Pu. Uranium and plutonium do not reciprocally interfere with one another until U/Pu ≅ 90 m/m. The fission product as interfering elements were also verified. Finally, uranium and plutonium were determined in simulated Purex Process solutions within the requested accuracy for control method. (author)

  17. Analysis of hyperspectral fluorescence images for poultry skin tumor inspection

    Kong, Seong G.; Chen, Yud-Ren; Kim, Intaek; Kim, Moon S.

    2004-02-01

    We present a hyperspectral fluorescence imaging system with a fuzzy inference scheme for detecting skin tumors on poultry carcasses. Hyperspectral images reveal spatial and spectral information useful for finding pathological lesions or contaminants on agricultural products. Skin tumors are not obvious because the visual signature appears as a shape distortion rather than a discoloration. Fluorescence imaging allows the visualization of poultry skin tumors more easily than reflectance. The hyperspectral image samples obtained for this poultry tumor inspection contain 65 spectral bands of fluorescence in the visible region of the spectrum at wavelengths ranging from 425 to 711 nm. The large amount of hyperspectral image data is compressed by use of a discrete wavelet transform in the spatial domain. Principal-component analysis provides an effective compressed representation of the spectral signal of each pixel in the spectral domain. A small number of significant features are extracted from two major spectral peaks of relative fluorescence intensity that have been identified as meaningful spectral bands for detecting tumors. A fuzzy inference scheme that uses a small number of fuzzy rules and Gaussian membership functions successfully detects skin tumors on poultry carcasses. Spatial-filtering techniques are used to significantly reduce false positives.

  18. Some applications of x-ray fluorescence spectrography to the determination of uranium and thorium

    Jones, R.W.

    1959-04-01

    Several methods for the determination of uranium and thorium by X-ray fluorescence spectrography are described. In pure solutions the sensitivity for these elements is 5-10 ppm. For solutions containing gross concentrations of impurities, strontium is added as an internal standard. Precision and accuracy of the determinations are about 1% when working in the optimum concentration range. (author)

  19. Determination of heavy metals in polar snow and ice by laser-excited atomic fluorescence spectrometry

    Bolshov, M.A.; Boutron, C.F.

    1994-01-01

    The new laser-excited atomic fluorescence spectrometry technique offers unrivalled sensitivity for the determination of trace metals in a wide variety of samples. This has allowed the direct determination of Pb, Cd and Bi in Antarctic and Greenland snow and ice down to the sub pg/g level. (authors). 11 refs., 2 figs

  20. The X-ray fluorescent method for determination of total sulphur in bituminous coals

    Widowska-Kusmierska, J.; Siess, K.

    1979-01-01

    The X-ray fluorescent technique for the determination of total sulphur covering concentrations from 0,1 to 10% has been applied for bituminous coals showing a great variability in qualitative and quantitative composition of mineral matter (ash). The described method is a quick one giving results during one hour. The obtained good accuracy of determinations gives prospects for wide industrial application. (author)

  1. Response of Substituted Indoleacetic Acids in the Indolo-alpha-pyrone Fluorescence Determination

    Engvild, Kjeld Christensen; Böttger, M.; Kaiser, P.

    1978-01-01

    .-pyrones. Other halogenated indoleacetic acids show between zero and 60% of the fluorescence of IAA. Apparently the concentration of IAA cannot be determined in crude extracts in the presence of 4-chloro- or 5-hydroxy-indoleacetic acid, because separate determinations of each of these compounds are not possible...

  2. Background approximation in automatic qualitative X-ray-fluorescent analysis

    Jordanov, J.; Tsanov, T.; Stefanov, R.; Jordanov, N.; Paunov, M.

    1982-01-01

    An empirical method of finding the dependence of the background intensity (Isub(bg) on the wavelength is proposed, based on the approximation of the experimentally found values for the background in the course of an automatic qualitative X-ray fluorescent analysis with pre-set curve. It is assumed that the dependence I(lambda) will be well approximated by a curve of the type Isub(bg)=(lambda-lambda sub(o)sup(fsub(1)(lambda))exp[fsub(2)(lambda)] where fsub(1) (lambda) and f 2 (lambda) are linear functions with respect to the sought parameters. This assumption was checked out on a ''pure'' starch background, in which it is not known beforehand which points belong to the background. It was assumed that the dependence I(lambda) can be found from all minima in the spectrum. Three types of minima has been distinguished: 1. the lowest point between two well-solved X-ray lines; 2. a minimum obtained as a result of statistical fluctuations of the measured signal; 3. the lowest point between two overlapped lines. The minima strongly deviating from the background are removed from the obtained set. The sum-total of the remaining minima serves as a base for the approximation of the dependence I(lambda). The unknown parameters are determined by means of the LSM. The approximated curve obtained by this method is closer to the real background than the background determined by the method described by Kigaki Denki, as the effect of all recorded minima is taken into account. As an example the PbTe spectrum recorded with crystal LiF 220 is shown graphically. The curve well describes the background of the spectrum even in the regions in which there are no minima belonging to the background. (authors)

  3. Determination of adenosine disodium triphosphate using prulifloxacin-terbium(III) as a fluorescence probe by spectrofluorimetry

    Yu Fengshan; Li Lin; Chen Fang

    2008-01-01

    A new spectrofluorimetric method is developed for determination of adenosine disodium triphosphate (ATP). The interactions between prulifloxacin (PUFX)-Tb 3+ complex and adenosine disodium triphosphate has been studied by using UV-vis absorption and fluorescence spectra. Using prulifloxacin-Tb 3+ as a fluorescence probe, under the optimum conditions, ATP can remarkably enhance the fluorescence intensity of the prulifloxacin-Tb 3+ complex at λ = 545 nm and the enhanced fluorescence intensity is in proportion to the concentration of ATP. Optimum conditions for the determination of ATP were also investigated. The dynamic range for the determination of ATP is 4.0 x 10 -7 to 2.0 x 10 -5 mol L -1 , and the detection limit (3 σ/k) is 1.7 x 10 -8 mol L -1 . This method is simple, practical and relatively free interference from coexisting substances and can be successfully applied to determination of ATP in real pharmaceutical samples. The mechanism of fluorescence enhancement of prulifloxacin-Tb 3+ complex by ATP was also discussed

  4. Analysis of root surface properties by fluorescence/Raman intensity ratio.

    Nakamura, Shino; Ando, Masahiro; Hamaguchi, Hiro-O; Yamamoto, Matsuo

    2017-11-01

    The aim of this study is to evaluate the existence of residual calculus on root surfaces by determining the fluorescence/Raman intensity ratio. Thirty-two extracted human teeth, partially covered with calculus on the root surface, were evaluated by using a portable Raman spectrophotometer, and a 785-nm, 100-mW laser was applied for fluorescence/Raman excitation. The collected spectra were normalized to the hydroxyapatite Raman band intensity at 960 cm -1 . Raman spectra were recorded from the same point after changing the focal distance of the laser and the target radiating angle. In seven teeth, the condition of calculus, cementum, and dentin were evaluated. In 25 teeth, we determined the fluorescence/Raman intensity ratio following three strokes of debridement. Raman spectra collected from the dentin, cementum, and calculus were different. After normalization, spectra values were constant. The fluorescence/Raman intensity ratio of calculus region showed significant differences compared to the cementum and dentin (p Raman intensity ratio decreased with calculus debridement. For this analysis, the delta value was defined as the difference between the values before and after three strokes, with the final 2 delta values close to zero, indicating a gradual asymptotic curve and the change in intensity ratio approximating that of individual constants. Fluorescence/Raman intensity ratio was effectively used to cancel the angle- and distance-dependent fluctuations of fluorescence collection efficiency during measurement. Changes in the fluorescence/Raman intensity ratio near zero suggested that cementum or dentin was exposed, and calculus removed.

  5. Embryonic lineage analysis using three-dimensional, time-lapse in-vivo fluorescent microscopy

    Minden, Jonathan; Kam, Zvi; Agard, David A.; Sedat, John W.; Alberts, Bruce

    1990-08-01

    Drosophila melanogaster has become one of the most extensively studied organisms because of its amenability to genetic analysis. Unfortunately, the biochemistry and cell biology ofDrosophila has lagged behind. To this end we have been microinjecting fluorescently labelled proteins into the living embryo and observing the behavior of these proteins to determine their role in the cell cycle and development. Imaging of these fluorescent probes is an extremely important element to this form of analysis. We have taken advantage of the sensitivity and well behaved characteristics of the charge coupled device (CCD) camera in conjunction with digital image enhancement schemes to produce highly accurate images of these fluorescent probes in vivo. One of our major goals is to produce a detailed map of cell fate so that we can understand how fate is determined and maintained. In order produce such a detailed map, protocols for following the movements and mitotic behavior of a large number of cells in three dimensions over relatively long periods of time were developed. We will present our results using fluorescently labelled histone proteins as a marker for nuclear location1. In addition, we will also present our initial results using a photoactivatable analog of fluorescein to mark single cells so that their long range fate can be unambiguously determined.

  6. A method for thickness determination of thin films of amalgamable metals by total-reflection X-ray fluorescence

    Bennun, L.; Greaves, E.D.; Barros, H.; Diaz-Valdes, J.

    2009-01-01

    A method for thickness determination of thin amalgamable metallic films by total-reflection X-ray fluorescence (TXRF) is presented. The peak's intensity in TXRF spectra are directly related to the surface density of the sample, i.e. to its thickness in a homogeneous film. Performing a traditional TXRF analysis on a thin film of an amalgamated metal, and determining the relative peak intensity of a specific metal line, the layer thickness can be precisely obtained. In the case of gold thickness determination, mercury and gold peaks overlap, hence we have developed a general data processing scheme to achieve the most precise results.

  7. Rare earth aerosol analysis by x-ray fluorescence spectrometry

    Citron, I.M.; Mausner, L.F.

    1982-01-01

    An analytical method for the determination of four lanthanides in air filter samples is described. The method involves simultaneous quantitative determinations of La, Ce, Pr, and Nd at the microgram level by x-ray fluorescence spectrometry without chemical separation of these rare earths and without serious interferences from the dust matrices on the filters. The method has been used successfully to analyze some air filter samples collected at a rare earth processing refinery in Illinois. A description of the development of the method is given as well as the results obtained by using this method on the air filter samples. The reproducibility of the results was generally +-5%

  8. Determination of ATP as a fluorescence probe with europium(III)-doxycycline.

    Hou, Faju; Wang, Xiaolei; Jiang, Chongqiu

    2005-03-01

    A new spectrofluorimetric method has been developed for the determination of adenosine disodium triphosphate (ATP). We studied the interactions between the doxycycline (DC)-Eu3+ complex and adenosine disodium triphosphate (ATP) by using UV-visible absorption and fluorescence spectra. Using doxycycline (DC)-Eu3+ as a fluorescence probe, under the optimum conditions, ATP could remarkably enhance the fluorescence intensity of the DC-Eu3+ complex at lambda = 612 nm. The enhanced fluorescence intensity of the Eu3+ ion was in proportion to the concentration of ATP. The optimum conditions for the determination of ATP were also investigated. The linear ranges for ATP were 1.00 x 10(-7) - 2.00 x 10(-6) mol L(-1) with detection limits of 4.07 x 10(-8) mol L(-1). This method is simple, practical and relatively free of interference from coexisting substances, and can be successfully applied to the determination of ATP in samples. The mechanism of fluorescence enhancement between the doxycycline (DC)-Eu3+ complex and ATP was also studied.

  9. Development of suitable plastic standards for X-ray fluorescence analysis

    Mans, Christian [University of Applied Sciences Muenster, Department of Chemical Engineering, Advanced Analytical Chemistry, Stegerwaldstr. 39, 48565 Steinfurt (Germany)], E-mail: c.mans@fh-muenster.de; Hanning, Stephanie [University of Applied Sciences Muenster, Department of Chemical Engineering, Advanced Analytical Chemistry, Stegerwaldstr. 39, 48565 Steinfurt (Germany)], E-mail: hanning@fh-muenster.de; Simons, Christoph [University of Applied Sciences Muenster, Department of Chemical Engineering, Advanced Analytical Chemistry, Stegerwaldstr. 39, 48565 Steinfurt (Germany)], E-mail: simons@fh-muenster.de; Wegner, Anne [University of Applied Sciences Muenster, Department of Chemical Engineering, Advanced Analytical Chemistry, Stegerwaldstr. 39, 48565 Steinfurt (Germany)], E-mail: awegner@fh-muenster.de; Janssen, Anton [University of Applied Sciences Muenster, Department of Chemical Engineering, Advanced Analytical Chemistry, Stegerwaldstr. 39, 48565 Steinfurt (Germany)], E-mail: janssena@fh-muenster.de; Kreyenschmidt, Martin [University of Applied Sciences Muenster, Department of Chemical Engineering, Advanced Analytical Chemistry, Stegerwaldstr. 39, 48565 Steinfurt (Germany)], E-mail: martin.kreyenschmidt@fh-muenster.de

    2007-02-15

    For the adoption of the EU directive 'Restriction on use of certain Hazardous Substances' and 'Waste Electrical and Electronic Equipment' using X-ray fluorescence analysis suitable standard materials are required. Plastic standards based on acrylonitrile-butadiene-styrene terpolymer, containing the regulated elements Br, Cd, Cr, Hg and Pb were developed and produced as granulates and solid bodies. The calibration materials were not generated as a dilution from one master batch but rather the element concentrations were distributed over nine independent calibration samples. This was necessary to enable inter-elemental corrections and empirical constant mass absorption coefficients. The produced standard materials are characterized by a homogenous element distribution, which is more than sufficient for X-ray fluorescence analysis. Concentrations for all elements except for Br could be determined by Inductively Coupled Plasma Atomic Emission Spectroscopy after microwave assisted digestion. The concentration of Br was determined by use of Neutron Activation Analysis at Hahn-Meitner-Institute in Berlin, Germany. The correlation of the X-ray fluorescence analysis measurements with the values determined using Inductively Coupled Plasma Atomic Emission Spectroscopy and Neutron Activation Analysis showed a very good linearity.

  10. Synchronous fluorescence based biosensor for albumin determination by cooperative binding of fluorescence probe in a supra-biomolecular host-protein assembly.

    Patra, Digambara

    2010-01-15

    A synchronous fluorescence probe based biosensor for estimation of albumin with high sensitivity and selectivity was developed. Unlike conventional fluorescence emission or excitation spectral measurements, synchronous fluorescence measurement offered exclusively a new synchronous fluorescence peak in the shorter wavelength range upon binding of chrysene with protein making it an easy identification tool for albumin determination. The cooperative binding of a fluorescence probe, chrysene, in a supramolecular host-protein assembly during various albumin assessments was investigated. The presence of supramolecular host molecules such as beta-cyclodextrin, curucurbit[6]uril or curucurbit[7]uril have little influence on sensitivity or limit of detection during albumin determination but reduced dramatically interference from various coexisting metal ion quenchers/enhancers. Using the present method the limit of detection for BSA and gamma-Globulin was found to be 0.005 microM which is more sensitive than reported values. Copyright 2009 Elsevier B.V. All rights reserved.

  11. Thorium determination by x-ray fluorescence spectrometry in simulated thorex process solutions

    Yamaura, M.; Matsuda, H.T.

    1991-11-01

    The X-ray fluorescence method for thorium determination in aqueous and organic (TBP/n-dodecane) solutions is described. The thin film technique for sample preparation and a suitable internal standard had been used. The best conditions for Thorium determination had been established studying some parameters as analytical line, internal standard, filter paper, paper geometry, sample volume and measurement conditions. With the established conditions, thorium was concentration range of to 200 g Th/L and in organic solutions (2-63g Th/L) with 1,5% of precision. The accuracy of the proposed method was 3% in aqueous and organic phases. The detection limit was 1,2μg thorium for aqueous solutions and 1,4μg for organic solutions. Uranium, fission products, corrosion products and Thorex reagent components were studied as interfering elements in the thorium analysis. The matrix effect was also studied using the Thorex process simulated solutions. Finally, the method was applied to thorium determination in irradiated thorium solutions with satisfactory results. (author)

  12. Determination of Ca/P molar ratio in hydroxyapatite (HA) by X-ray fluorescence technique

    Scapin, Marcos A.; Guilhen, Sabine N.; Cotrim, Marycel E.B.; Pires, Maria Ap. F., E-mail: mascapin@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    Hydroxyapatite (HA) is a mineral composed of calcium phosphate employed for endodontics, restorative dentistry and other applications in orthopedics and prosthesis. Additionally, this biomaterial is an inexpensive but efficient adsorbent for the removal of heavy metals and other unwanted species of contaminated liquid effluents. This is especially interesting when low-cost effective remediation is required. A Ca / P molar ratio of 1.667 is consistent with the theoretical Ca / P ratio for calcium hydroxyapatite with a compositional formula of Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2}, which properties are well discussed in the literature. The aim of this work was to implement and validate a methodology for simultaneous determination of major and minor constituents in the hydroxyapatite (HA) as well as providing the Ca / P molar ratio. To accomplish these achievements, wavelength dispersive X-ray fluorescence spectroscopy (WDXRF) was applied. This is a non-destructive technique that requires no chemical treatment, enabling fast chemical analysis in a wide variety of samples, with no hazardous waste being generated as a result of the process of determination. A standard reference material from NIST (SRM 1400 – Bone Ash) was used to validate the methodology for the determination of magnesium, phosphorus, potassium, calcium, iron, zinc, strontium and the Ca / P ratio in HA samples by WDXRF. The Z-score test was applied as a statistical tool and showed that the calculated values were of less than 1.8 for all the measured analytes. (author)

  13. Determination of Ca/P molar ratio in hydroxyapatite (HA) by X-ray fluorescence technique

    Scapin, Marcos A.; Guilhen, Sabine N.; Cotrim, Marycel E.B.; Pires, Maria Ap. F.

    2015-01-01

    Hydroxyapatite (HA) is a mineral composed of calcium phosphate employed for endodontics, restorative dentistry and other applications in orthopedics and prosthesis. Additionally, this biomaterial is an inexpensive but efficient adsorbent for the removal of heavy metals and other unwanted species of contaminated liquid effluents. This is especially interesting when low-cost effective remediation is required. A Ca / P molar ratio of 1.667 is consistent with the theoretical Ca / P ratio for calcium hydroxyapatite with a compositional formula of Ca 10 (PO 4 ) 6 (OH) 2 , which properties are well discussed in the literature. The aim of this work was to implement and validate a methodology for simultaneous determination of major and minor constituents in the hydroxyapatite (HA) as well as providing the Ca / P molar ratio. To accomplish these achievements, wavelength dispersive X-ray fluorescence spectroscopy (WDXRF) was applied. This is a non-destructive technique that requires no chemical treatment, enabling fast chemical analysis in a wide variety of samples, with no hazardous waste being generated as a result of the process of determination. A standard reference material from NIST (SRM 1400 – Bone Ash) was used to validate the methodology for the determination of magnesium, phosphorus, potassium, calcium, iron, zinc, strontium and the Ca / P ratio in HA samples by WDXRF. The Z-score test was applied as a statistical tool and showed that the calculated values were of less than 1.8 for all the measured analytes. (author)

  14. Simultaneous determination of Magnolol and Honokiol by amino acid ionic liquid synchronous fluorescence spectrometry

    Liu, Wei; Zhu, Xiashi

    2018-05-01

    A novel method based on amino acid ionic liquids (AAILs) as an additive synchronous fluorescence spectrometry is proposed for simultaneous determination of magnolol (MN) and honokiol (HN) in traditional Chinese medicine Houpu. The overlapping fluorescence spectrum of MN and HN could be completely separated in the AAILs medium. Experiment parameters (the type and concentration of AAILs, pH values and temperature) were discussed. The detection limits of MN and HN reached 1.46 ng/mL, 0.92 ng/mL and the recovery rates ranged from 98.6%-100.7%, 99.7%-100.6%, respectively. This methods was successfully employed for simultaneously determination of MN and HN in real samples. No significant differences could be found in the results of this method and the pharmacopoeia of People's Republic of China 2015 (Ch.P.2015). The experiment mechanisms were discussed by the Gaussian simulation and fluorescence quantum yield.

  15. Single particle transfer for quantitative analysis with total-reflection X-ray fluorescence spectrometry

    Esaka, Fumitaka; Esaka, Konomi T.; Magara, Masaaki; Sakurai, Satoshi; Usuda, Shigekazu; Watanabe, Kazuo

    2006-01-01

    The technique of single particle transfer was applied to quantitative analysis with total-reflection X-ray fluorescence (TXRF) spectrometry. The technique was evaluated by performing quantitative analysis of individual Cu particles with diameters between 3.9 and 13.2 μm. The direct quantitative analysis of the Cu particle transferred onto a Si carrier gave a discrepancy between measured and calculated Cu amounts due to the absorption effects of incident and fluorescent X-rays within the particle. By the correction for the absorption effects, the Cu amounts in individual particles could be determined with the deviation within 10.5%. When the Cu particles were dissolved with HNO 3 solution prior to the TXRF analysis, the deviation was improved to be within 3.8%. In this case, no correction for the absorption effects was needed for quantification

  16. Sample analysis using gamma ray induced fluorescent X-ray emission

    Sood, B S; Allawadhi, K L; Gandhi, R; Batra, O P; Singh, N [Punjabi Univ., Patiala (India). Nuclear Science Labs.

    1983-01-01

    A non-destructive method for the analysis of materials using gamma ray-induced fluorescent x-ray emission has been developed. In this method, special preparation of very thin samples in which the absorption of the incident gamma rays and the emitted fluorescent x-rays is negligible, is not needed, and the absorption correction is determined experimentally. A suitable choice of the incident gamma ray energies is made to minimise enhancement effects through selective photoionization of the elements in the sample. The method is applied to the analysis of a typical sample of the soldering material using 279 keV and 59.5 keV gamma rays from /sup 203/Hg and /sup 241/Am radioactive sources respectively. The results of the analysis are found to agree well with those obtained from the chemical analysis.

  17. [Fluorescence Determination of Trace Se with the Hydride-K13-Rhodamine 6G System].

    Liang, Ai-hui; Li, Yuan; Huang, Shan-shan; Luo, Yang-he; Wen, Gui-qing; Jiang, Zhi-liang

    2015-05-01

    Se is a necessary trace element for human and animals, but the excess intake of Se caused poison. Thus, it is very important to determination of Se in foods and water. The target of this study is development of a new, sensitive and selective hydride generation-molecular fluorescence method for the determination of Se. In 0. 36 mol . L-1 sulfuric acid, NaBH4 as reducing agent, Se (IV) is reduced to H2 Se. Usin3-g I solution as absorption liquid3, I- is reduced to I- by H2Se. When adding rhodamine 6G, Rhodamine 6G and I3- form association particles, which lead to the fluorescence intensity decreased. When Se(IV) existing, Rhodamine 6G and I3- bind less, And the remaining amount of Rhodamine 6G increase. So the fluorescence intensity is enhanced. The analytical conditions were optimized, a 0. 36 ml . L-1 H2SO4, 21. 6.g . L-1 NaBH4, 23.3 µm . L-1 rhodamine 6G, and 50 µmol . L-1 KI3 were chosen for use. When the excitation wavelength is at 480nm, the Rayleigh scattering peak does not affect the fluorescence recording, and was selected for determination of Se. Under the selected conditions, Se(IV) concentration in the 0. 02~0. 60 µg . mL-1 range and the increase value of the fluorescence intensity (ΔF) at 562 nm linear relationship. The linear regression equation is ΔF562 nm =12. 6c + 20. 9. The detecton limit was 0.01 µ.g . L-1. The influence of coexistence substances on the hydride generatin-molecular fluorescence determination of 5. 07 X10(-6) mol . L-1 Se(IV) was considered in details. Results showed that this new fluorescence method is of high selectivity, that is, 0. 5 mmol. L-1 Ba2+, Ca2+, Zn2+ and Fe3+, 0. 25 mmol . L-1 . Mg2+, 0. 05 mmol . L-1 K+, 0. 2 mmol . L-1 Al3+, 0. 025 mmol . L-1 Te(VI) do not interfere with the determination. The influence of Hg2+, CD2+ and Cu2+ that precipitate with Se(IV), can be eliminated by addition of complex reagent. This hydride generation-molecular fluorescence method has been applied to determination of trace Se in water

  18. Determination of HER2 and p53 Mutations by Sequence Analysis Method and EGFR/Chromosome 7 Gene Status by Fluorescence in Situ Hybridization for the Predilection of Targeted Therapy Modalities in Immunohistochemically Triple Negative Breast Carcinomas in Turkish Population.

    Pala, Emel Ebru; Bayol, Umit; Keskin, Elif Usturali; Ozguzer, Alp; Kucuk, Ulku; Ozer, Ozge; Koc, Altug

    2015-09-01

    Triple negative breast cancer (TNBC), an agressive subtype accounts nearly 15 % of all breast carcinomas. Conventional chemotherapy is the only treatment modality thus new, effective targeted therapy methods have been investigated. Epidermal growth factor receptor (EGFR) inhibitors give hope according to the recent studies results. Also therapeutic agents have been tried against aberrant p53 signal activity as TNBC show high p53 mutation rates. Our aim was to detect the incidence of mutations/amplifications identified in TNBC in our population. Here we used sequence analysis to detect HER2 (exon 18-23), p53 (exon 5-8) mutations; fluorescence in situ hybridization (FISH) method to analyse EGFR/chromosome 7 centromere gene status in 82 immunohistochemically TNBC. Basaloid phenotype was identified in 49 (59.8 %) patients. EGFR amplification was noted in 5 cases (6.1 %). All EGFR amplified cases showed EGFR overexpression by immunohistochemistry (IHC). p53 mutations were identified in 33 (40.2 %) cases. Almost 60 % of the basal like breast cancer cases showed p53 mutation. Only one case showed HER2 mutation (exon 20:g.36830_3). Our results showed that gene amplification is not the unique mechanism in EGFR overexpression. IHC might be used in the decision of anti-EGFR therapy in routine practice. p53 mutation rate was lower than the rates reported in the literature probably due to ethnic differences and low sensitivity of sanger sequences in general mutation screening. We also established the rarity of HER2 mutation in TNBC. In conclusion EGFR and p53 are the major targets in TNBC also for our population.

  19. Quantitative determination of Sulfur and Chlorine in Crude Oils by x-ray fluorescence spectrometry

    Ayala Jimenez, R.E.

    1986-01-01

    Given the importance of sulfur and chlorine content in crude petroleum, and that the actual methods used in the country to its determination are slow and cumbersome, the present work consisted in applying a new method, based on X-ray fluorescence spectrometry, to make this analysis as fast as possible with greater sensibility and precision. Samples of crude petroleum were analyzed using two different quantitative methods: a) through calibration curves elaborated with standard aqueous solutions of inorganic salts of S and Cl and b) through standard addition method using CS 2 as standard for S and CCl 4 for Cl. The measuring system consisted of Fe-55 radioactive source (10 mCi), Si-Li semiconductor detector, spectrum amplifier, multichannel analyzer and a DIGITAL Computer. The peak areas and their deviations were obtained through AXIL software. The values of area and deviation joined to weight of sample and amount of standard added were used to calculate the concentration of the analite and its deviation. In conclusion, calibration curves enable only semiquantitative analysis. However, the standard addition method has advantages over ASTM methods D 129-64 and D 808-63 for sulfur and chlorine respectively. The main advantage is the great speed with which an analysis is made: 20 minutes, while ASTM methods need approximately 16 hours. Likewise it was obtained: sensibility 0.05%; accuracy: maximum 0.02%, minimum 10%; and precision: maximum 2%, minimum 10%. (author)

  20. Study on fluorescence properties of carbogenic nanoparticles and their application for the determination of ferrous succinate

    Sun Wen [Department of Analytical Chemistry, China Pharmaceutical University, Nanjing 210009 (China); Du Yingxiang, E-mail: du_yingxiang@126.co [Department of Analytical Chemistry, China Pharmaceutical University, Nanjing 210009 (China) and Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education, China Pharmaceutical University, Nanjing 210009 (China) and Key Laboratory of Modern Chinese Medicines, Ministry of Education, China Pharmaceutical University, Nanjing 210009 (China); Wang Yunqing [Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003 (China)

    2010-08-15

    A new type of fluorescent nanomaterial named carbogenic nanoparticles (NPs) has drawn considerable attention recently. In this study, we adopted a direct and simple synthetic method to produce the carbogenic NPs and investigated the fluorescence properties of the as-prepared carbogenic NPs in detail. It was found that the fluorescence of carbogenic NPs was stable with the variance of environmental conditions such as pH, temperature and UV irradiation. More interestingly, we found carbogenic NPs exhibited high selectivity and sensitivity towards ferric ions. Under optimum conditions, a good linear relationship could be obtained between the fluorescence intensity and concentration of ferric ions in the range of 5.0x10{sup -5}-5.0x10{sup -4} mol L{sup -1}, and the limit of detection is 11.2 {mu}mol L{sup -1}. Based on the fluorescence quenching of carbogenic NPs, a rapid and specific quantitative method was proposed for the determination of ferrous succinate. The content of ferrous succinate in commercial tablets determined by the present method was agreed with the spectrophotometric method results and the reproducibility and the recovery of the proposed method were satisfactory.

  1. The lipid dependence of melittin action investigated by dual-color fluorescence burst analysis

    Bogaart, Geert van den; Mika, Jacek T.; Krasnikov, Viktor; Poolman, Bert

    Dual-color fluorescence-burst analysis was used to study melittin-induced leakage of macromolecules from liposomes of various lipid compositions. To perform dual-color fluorescence-burst analysis, fluorescently labeled size-marker molecules were encapsulated into liposomes, labeled with a second

  2. Tools for the quantitative analysis of sedimentation boundaries detected by fluorescence optical analytical ultracentrifugation.

    Huaying Zhao

    Full Text Available Fluorescence optical detection in sedimentation velocity analytical ultracentrifugation allows the study of macromolecules at nanomolar concentrations and below. This has significant promise, for example, for the study of systems of high-affinity protein interactions. Here we describe adaptations of the direct boundary modeling analysis approach implemented in the software SEDFIT that were developed to accommodate unique characteristics of the confocal fluorescence detection system. These include spatial gradients of signal intensity due to scanner movements out of the plane of rotation, temporal intensity drifts due to instability of the laser and fluorophores, and masking of the finite excitation and detection cone by the sample holder. In an extensive series of experiments with enhanced green fluorescent protein ranging from low nanomolar to low micromolar concentrations, we show that the experimental data provide sufficient information to determine the parameters required for first-order approximation of the impact of these effects on the recorded data. Systematic deviations of fluorescence optical sedimentation velocity data analyzed using conventional sedimentation models developed for absorbance and interference optics are largely removed after these adaptations, resulting in excellent fits that highlight the high precision of fluorescence sedimentation velocity data, thus allowing a more detailed quantitative interpretation of the signal boundaries that is otherwise not possible for this system.

  3. Fluorescent foci quantitation for high-throughput analysis

    Elena Ledesma-Fernández

    2015-06-01

    Full Text Available A number of cellular proteins localize to discrete foci within cells, for example DNA repair proteins, microtubule organizing centers, P bodies or kinetochores. It is often possible to measure the fluorescence emission from tagged proteins within these foci as a surrogate for the concentration of that specific protein. We wished to develop tools that would allow quantitation of fluorescence foci intensities in high-throughput studies. As proof of principle we have examined the kinetochore, a large multi-subunit complex that is critical for the accurate segregation of chromosomes during cell division. Kinetochore perturbations lead to aneuploidy, which is a hallmark of cancer cells. Hence, understanding kinetochore homeostasis and regulation are important for a global understanding of cell division and genome integrity. The 16 budding yeast kinetochores colocalize within the nucleus to form a single focus. Here we have created a set of freely-available tools to allow high-throughput quantitation of kinetochore foci fluorescence. We use this ‘FociQuant’ tool to compare methods of kinetochore quantitation and we show proof of principle that FociQuant can be used to identify changes in kinetochore protein levels in a mutant that affects kinetochore function. This analysis can be applied to any protein that forms discrete foci in cells.

  4. Rapid extraction and x-ray fluorescence determination of gold in rock

    Lobanov, F.I.; Logunova, S.A.; Popov, A.M.; Krasnopevtseva, E.V.

    1994-01-01

    The optimal conditions for gold extractional recovery by melts of aliphatic monocarboxylic acids mixtures (C ≥ 16) with additions of di-2-ethylhexyldithiophosphoric acid, di-n-oxtylsulfide and alkylaniline were determined. A rapid method of extraction and X-ray fluorescence detection of gold in the presence of considerable amounts of Fe, Cu, Pb, Cd, Zn and Bi was developed

  5. Determination of uranium in geologic materials by laser-excited fluorescence

    McHugh, J.B.

    1982-01-01

    A laser-excited fluorescence method is described for the determination of trace amounts of uranium in rocks and soils. The limit of detection is less than 1 ppm, and the relative standard deviation ranges from 2.6 to 12.5%. The method was evaluated by using known geological reference samples

  6. A sensitive fluorescence quenching method for determination of bismuth with tiron

    Taher, Mohammad Ali; Rahimi, Mina [Department of Chemistry, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Fazelirad, Hamid, E-mail: hamidfazelirad@gmail.com [Department of Chemistry, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Department of Chemistry, Science and Research Branch, Islamic Azad University, Yazd (Iran, Islamic Republic of); Young Researchers Society, Shahid Bahonar University of Kerman, P.O. Box 76175-133, Kerman (Iran, Islamic Republic of)

    2014-01-15

    We describe a fluorescence quenching method for determination of bismuth with tiron. The method is based on the reaction of tiron by bismuth(III) in acidic media. The influence of variables such as the pH, type of buffer, tiron concentration, reaction time and temperature were investigated. Under optimized conditions, the fluorescence quenching extent is proportional to the concentration of bismuth for Bi–tiron system at the range 0.13–2.09 μg mL{sup −1} and the detection limit is 0.05 μg mL{sup −1}. The proposed sensor presented good repeatability, evaluated in terms of relative standard deviation (R.S.D.=±0.498%) for 11 replicates. This sensitive, rapid and accurate method has been successfully applied to the determination of trace bismuth(III) in water and hair samples and certified reference materials. -- Highlights: • No previous paper report on use of fluorescence quenching for determination of Bi. • Fluorescence quenching of trion is a sensitive method for determination of Bi(III). • Under the optimum conditions the detection limit is very low (0.05 μg mL{sup −1}). • The procedure is simple and safe and has high tolerance limit to interferences.

  7. Determination of acetylsalicylic acid and salicylic acid in foods, using HPLC with fluorescence detection.

    Venema, D.P.; Hollman, P.C.H.; Janssen, P.L.T.M.K.; Katan, M.B.

    1996-01-01

    We developed a specific and sensitive HPLC method with fluorescence detection for the determination of free acetylsalicylic acid, free salicylic acid, and free salicylic acid plus salicylic acid after alkaline hydrolysis (free-plus-bound) in foods. Acetylsalicylic acid was detected after postcolumn

  8. Determination of rhenium in molybdenite by X-ray fluorescence: A combined chemical-spectrometric technique.

    Solt, M W; Wahlberg, J S; Myers, A T

    1969-01-01

    Rhenium in molybdenite is separated from molybdenum by distillation of rhenium heptoxide from a perchloric-sulphuric acid mixture. It is concentrated by precipitation of the sulphide and then determined by X-ray fluorescence. From 3 to 1000 microg of rhenium can be measured with a precision generally within 2%. The procedure tolerates larger amounts of molybdenum than the usual colorimetric methods.

  9. Determination of rhenium in molybdenite by X-ray fluorescence. A combined chemical-spectrometric technique

    Solt, M.W.; Wahlberg, J.S.; Myers, A.T.

    1969-01-01

    Rhenium in molybdenite is separated from molybdenum by distillation of rhenium heptoxide from a perchloric-sulphuric acid mixture. It is concentrated by precipitation of the sulphide and then determined by X-ray fluorescence. From 3 to 1000 ??g of rhenium can be measured with a precision generally within 2%. The procedure tolerates larger amounts of molybdenum than the usual colorimetric methods. ?? 1969.

  10. Determination of the shell growth direction during the formation of silica microcapsules by confocal fluorescence microscopy

    van Wijk, J.; Salari, J.W.O.; Meuldijk, J.; Klumperman, L.

    2015-01-01

    A novel procedure was developed to determine the direction of silica growth during the formation of a silica shell around aqueous microdroplets in water-in-oil Pickering emulsions. Two fluorescently labeled silica precursors were added consecutively and the resulting microcapsules were visualized

  11. X-ray fluorescence analysis of neodymium oxide/oxalate for rare earth impurities

    Chandola, L.C.; Mohile, A.N.

    1977-01-01

    An X-ray fluorescence method for the determination of cesium, praseodymium, samarium, europium and gadolinium in pure neodymium oxide and oxalate is described. The oxide sample is converted to oxalate and mixed with a binder (boric acid) to obtain a pressed circular pellet. The amount of sample needed for analysis is reduced by making use of the double layer pellet technique. A tungsten target X-ray tube is employed to irradiate the sample and a Philips PW 1220 semiautomatic X-ray spectrometer with a LiF (200) crystal is used to analyse the fluorescent X-rays. The minimum determination limit is 0.01 percent for all rare earths determined except for europium for which the limit is 0.005 percent. Three sigma detection limits have been calculated. (author)

  12. Quantitative analysis of essential oils of Thymus daenensis using laser-induced fluorescence and Raman spectroscopy.

    Khoshroo, H; Khadem, H; Bahreini, M; Tavassoli, S H; Hadian, J

    2015-11-10

    Laser-induced fluorescence and Raman spectroscopy are used for the investigation of different genotypes of Thymus daenensis native to the Ilam province of Iran. Different genotypes of T. daenensis essential oils, labeled T1 through T7, possess slight differences with regard to the composition of the thymol. The gas chromatography-mass spectrometry (GC-MS) method is performed to determine the concentration of each constituent as a reference method. The Raman spectra of different concentrations of pure thymol dissolved in hexane as standard samples are obtained via a laboratory prototype Raman spectroscopy setup for the calculation of the calibration curve. The regression coefficient and limit of detection are calculated. The possibility of the differentiation of different genotypes of T. daenensis is also examined by laser-induced fluorescence spectroscopy, although we do not know the exact amounts of their components. All the fluorescence spectral information is used jointly by cluster analysis to differentiate between 7 genotypes. Our results demonstrate the acceptable precision of Raman spectroscopy with GC-MS and corroborate the capacity of Raman spectroscopy in applications in the quantitative analysis field. Furthermore, the cluster analysis results show that laser-induced fluorescence spectroscopy is an acceptable technique for the rapid classification of different genotypes of T. daenensis without having any previous information of their exact amount of constituents. So, the ability to rapidly and nondestructively differentiate between genotypes makes it possible to efficiently select high-quality herbs from many samples.

  13. Romanian medieval earring analysis by X-ray fluorescence technique

    Therese, Laurent; Guillot, Philippe; Muja, Cristina

    2011-01-01

    Full text: Several instrumental techniques of elemental analysis are now used for the characterization of archaeological materials. The combination between archaeological and analytical information can provide significant knowledge on the constituting material origin, heritage authentication and restoration, provenance, migration, social interaction and exchange. Surface mapping techniques such as X-Ray Fluorescence have become a powerful tool for obtaining qualitative and semi-quantitative information about the chemical composition of cultural heritage materials, including metallic archaeological objects. In this study, the material comes from the Middle Age cemetery of Feldioara (Romania). The excavation of the site located between the evangelical church and the parsonage led to the discovery of several funeral artifacts in 18 graves among a total of 127 excavated. Even if the inventory was quite poor, some of the objects helped in establishing the chronology. Six anonymous Hungarian denarii (silver coins) were attributed to Geza II (1141-1161) and Stefan III (1162-1172), placing the cemetery in the second half of the XII century. This period was also confirmed by three loop shaped earrings with the end in 'S' form (one small and two large earrings). The small earring was found during the excavation in grave number 86, while the two others were discovered together in grave number 113. The anthropological study shown that skeletons excavated from graves 86 and 113 belonged respectively to a child (1 individual, medium level preservation, 9 months +/- 3 months) and to an adult (1 individual). In this work, elemental mapping were obtained by X-ray fluorescence (XRF) technique from Jobin Yvon Horiba XGT-5000 instrument offering detailed elemental images with a spatial resolution of 100μm. The analysis revealed that the earrings were composed of copper, zinc and tin as major elements. Minor elements were also determined. The comparison between the two large earrings

  14. Romanian medieval earring analysis by X-ray fluorescence technique

    Therese, Laurent; Guillot, Philippe, E-mail: philippe.guillot@univ-jfc.fr [Laboratoire Diagnostics des Plasmas, CUFR J.F.C, Albi (France); Muja, Cristina [Laboratoire Diagnostics des Plasmas, CUFR J.F.C, Albi (France); Faculty of Biology, University of Bucharest (Romania); Vasile Parvan Institute of Archaeology, Bucharest, (Romania)

    2011-07-01

    Full text: Several instrumental techniques of elemental analysis are now used for the characterization of archaeological materials. The combination between archaeological and analytical information can provide significant knowledge on the constituting material origin, heritage authentication and restoration, provenance, migration, social interaction and exchange. Surface mapping techniques such as X-Ray Fluorescence have become a powerful tool for obtaining qualitative and semi-quantitative information about the chemical composition of cultural heritage materials, including metallic archaeological objects. In this study, the material comes from the Middle Age cemetery of Feldioara (Romania). The excavation of the site located between the evangelical church and the parsonage led to the discovery of several funeral artifacts in 18 graves among a total of 127 excavated. Even if the inventory was quite poor, some of the objects helped in establishing the chronology. Six anonymous Hungarian denarii (silver coins) were attributed to Geza II (1141-1161) and Stefan III (1162-1172), placing the cemetery in the second half of the XII century. This period was also confirmed by three loop shaped earrings with the end in 'S' form (one small and two large earrings). The small earring was found during the excavation in grave number 86, while the two others were discovered together in grave number 113. The anthropological study shown that skeletons excavated from graves 86 and 113 belonged respectively to a child (1 individual, medium level preservation, 9 months +/- 3 months) and to an adult (1 individual). In this work, elemental mapping were obtained by X-ray fluorescence (XRF) technique from Jobin Yvon Horiba XGT-5000 instrument offering detailed elemental images with a spatial resolution of 100{mu}m. The analysis revealed that the earrings were composed of copper, zinc and tin as major elements. Minor elements were also determined. The comparison between the two

  15. Time-Gated Raman Spectroscopy for Quantitative Determination of Solid-State Forms of Fluorescent Pharmaceuticals.

    Lipiäinen, Tiina; Pessi, Jenni; Movahedi, Parisa; Koivistoinen, Juha; Kurki, Lauri; Tenhunen, Mari; Yliruusi, Jouko; Juppo, Anne M; Heikkonen, Jukka; Pahikkala, Tapio; Strachan, Clare J

    2018-04-03

    Raman spectroscopy is widely used for quantitative pharmaceutical analysis, but a common obstacle to its use is sample fluorescence masking the Raman signal. Time-gating provides an instrument-based method for rejecting fluorescence through temporal resolution of the spectral signal and allows Raman spectra of fluorescent materials to be obtained. An additional practical advantage is that analysis is possible in ambient lighting. This study assesses the efficacy of time-gated Raman spectroscopy for the quantitative measurement of fluorescent pharmaceuticals. Time-gated Raman spectroscopy with a 128 × (2) × 4 CMOS SPAD detector was applied for quantitative analysis of ternary mixtures of solid-state forms of the model drug, piroxicam (PRX). Partial least-squares (PLS) regression allowed quantification, with Raman-active time domain selection (based on visual inspection) improving performance. Model performance was further improved by using kernel-based regularized least-squares (RLS) regression with greedy feature selection in which the data use in both the Raman shift and time dimensions was statistically optimized. Overall, time-gated Raman spectroscopy, especially with optimized data analysis in both the spectral and time dimensions, shows potential for sensitive and relatively routine quantitative analysis of photoluminescent pharmaceuticals during drug development and manufacturing.

  16. Foliar Reflectance and Fluorescence Responses for Plants Under Nitrogen Stress Determined with Active and Passive Systems

    Middleton, E. M.; McMurtrey, J. E.; Campbell, P. K. Entcheva; Corp, L. A.; Butcher, L. M.; Chappelle, E. W.

    2003-01-01

    Vegetation productivity is driven by nitrogen (N) availability in soils. Both excessive and low soil N induce physiological changes in plant foliage. In 2001, we examined the use of spectral fluorescence and reflectance measurements to discriminate among plants provided different N fertilizer application rates: 20%, 50%, 100% and 150% of optimal N levels. A suite of optical, fluorescence, and biophysical measurements were collected on leaves from field grown corn (Zea mays L.) and soybean plants (Glycine max L.) grown in pots (greenhouse + ambient sunlight daily). Three types of steady state laser-induced fluorescence measurements were made on adaxial and abaxial surfaces: 1) fluorescence images in four 10 nm bands (blue, green, red, far-red) resulting from broad irradiance excitation; 2) emission spectra (5 nm resolution) produced by excitation at single wavelengths (280,380 or 360, and 532 nm); and 3) excitation spectra (2 nm resolution), with emission wavelengths fixed at wavelengths centered on selected solar Fraunhofer lines (532,607,677 and 745 nm). Two complementary sets of high resolution (less than 2 nm) optical spectra were acquired for both adaxial and abaxial leaf surfaces: 1) optical properties (350-2500 nm) for reflectance, transmittance, and absorptance; and 2) reflectance spectra (500-1000 nm) acquired with and without a short pass filter at 665 nm to determine the fluorescence contribution to apparent reflectance in the 650-750 spectrum, especially at the 685 and 740 nm chlorophyll fluorescence (ChIF) peaks. The strongest relationships between foliar chemistry and optical properties were demonstrated for C/N content and two optical parameters associated with the red edge inflection point. Select optical properties and ChIF parameters were highly correlated for both species. A significant contribution of ChIF to apparent reflectance was observed, averaging 10-25% at 685 nm and 2 - 6% at 740 nm over all N treatments. Discrimination of N treatment

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

    Toeroek, Sz.; Szoekefalvi-Nagy, Z.

    1982-06-01

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

  18. Energy dispersion X-ray fluorescence techniques in water pollution analysis

    Holynska, B.

    1980-01-01

    Advantages and limitations of energy dispersion X-ray fluorescence methods for analysis of pollutants in water are discussed. The necessary equipment for X-ray measurement of insoluble and dissolved trace metals in water is described. Different techniques of enrichment of trace metals are presented: ion exchange on selective Chelex-100 exchanger, precipitation with chelating agents DDTC and APDC, and adsorption on activated carbon. Some results obtained using different preconcentration methods for trace metals determination in different waters are presented. (author)

  19. Determination of the dispersion coefficient, in rivers through radioactive and fluorescent tracers

    Almeida Rosso, T.C. de.

    1986-03-01

    The purpose of this work was to determine experimentally the dispersion coefficient in natural streams through the aplication of radioactive and fluorescent tracers. The technique used to obtain the experimental data was the simmultaneous injection of the radioactive tracer Bromim - 82 and the fluorescent ones, Amidorodamine G. extra and Uranine. A comparison among these different tracers is shown as well as the performance of Uranine in a poluented stream in the presence of suspended sediments. The site chosen for the experiments was the Piabanha River, between Pedro do Rio and Areal, located at Rio de Janeiro state, in a nearly 20 Km strech. (Author) [pt

  20. Utilization of Photochemically Induced Fluorescence Detection for HPLC Determination of Genotoxic Impurities in the Vortioxetine Manufacturing Process.

    Douša, Michal; Doubský, Jan; Srbek, Jan

    2016-07-01

    An analytical reversed-phase high-performance liquid chromatography (HPLC) method for the detection and quantitative determination of two genotoxic impurities at ppm level present in the vortioxetine manufacturing process is described. Applying the concept of threshold of toxicological concern, a limit of 75 ppm each for both genotoxic impurities was calculated based on the maximum daily dose of active pharmaceutical ingredients. The novel reversed-phase HPLC method with photochemically induced fluorescence detection was developed on XSELECT Charged Surface Hybrid Phenyl-Hexyl column using the mobile phase consisted a mixture of 10 mM ammonium formate pH 3.0 and acetonitrile. The elution was performed using an isocratic composition of 48:52 (v/v) at a flow rate of 1.0 mL/min. The photochemically induced fluorescence detection is based on the use of UV irradiation at 254 nm through measuring the fluorescence intensity at 300 nm and an excitation wavelength of 272 nm to produce fluorescent derivatives of both genotoxic impurities. The online photochemical conversion and detection is easily accomplished for two expected genotoxic impurities and provides a sufficiently low limit detection and quantification for the target analysis. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  1. Spectrofluorimetric determination of gemifloxacin mesylate and linezolid in pharmaceutical formulations: Application of quinone-based fluorophores and enhanced native fluorescence

    Moussa Bahia Abbas

    2014-03-01

    Full Text Available Quinone-based fluorophores and enhanced native fluorescence techniques were applied for a fast quantitative analysis of gemifloxacin mesylate (GEM and linezolid (LIN in pharmaceutical formulations. For this purpose, three sensitive, accurate and precise spectrofluorimetric methods were developed. GEM, as an n-electron donor, reacts with 7,7,8,8-tetracyanoquinodimethane (method A and 2,5-dichloro-3,6-dihydroxy-p-benzoquinone (method B as п-electron acceptors, forming charge transfer complexes that exhibit high fluorescence intensity at 441 and 390 nm upon excitation at 260 and 339 nm, respectively. Method C depends on measurement of enhanced native fluorescence of LIN in phosphate buffer (pH 5 at 380 nm upon excitation at 260 nm. Experimental factors affecting fluorescence intensity were optimized. Linearity was obtained over concentration ranges 50-500, 10-60 and 20-400 ng mL-1 for methods A, B and C, respectively. The developed methods were validated and successfully applied for determination of the cited drugs in tablets.

  2. Ultratrace analysis of transuranic actinides by laser-induced fluorescence

    Miller, S.M.

    1983-10-31

    Ultratrace quantities of transuranic actinides are detected indirectly by their effect on the fluorescent emissions of a preselected fluorescent species. Transuranic actinides in a sample are coprecipitated with a host lattice material containing at least one preselected fluorescent species. The actinide either quenches or enhances the laser-induced fluorescence of the preselected fluorescent species. The degree of enhancement or quenching is quantitatively related to the concentration of actinide in the sample.

  3. Determination of trace elements and heavy metals in sediment using x-ray fluorescence

    Sidahmed, Muataz Ahmed Ibrahem

    2014-01-01

    In this study, 30 sediment samples were taken randomly from the area of Suba south of Khartoum state. Trace elements and heavy metal were determined in sediments samples using x-ray fluoresce spectroscopy (X RF). K, Ca, Ti, Mn, Fe, Cu, Zn, Pb, Rb, Sr, and Zr were determined by X RF. Standard Reference Material (SRM) from international Atomic Energy Agency (IAEA-Soil-7) has been used to achieve accuracy of X RF method. Measured values were found in agreements with certified values. The average elemental concentrations of K, Ca, Ti, Mn, Fe, Cu, Zn, Pb, Rb, Sr, and Zr were 5882.7, 20703.3, 6264.3, 460.97, 26713.3, 7.7, 43.4, 18.6, 28.6, 144.8, and 173.06, respectively. Correlation between elements was performed also cluster analysis was used to check the similarly between the samples result. The result of study were compared with previous studies and the concentrations of some elements found to be similar.(Author)

  4. The determination of molybdenum and tungsten in resin by x-ray-fluorescence spectrometry

    Eddy, B.T.

    1985-01-01

    This report describes a method using X-ray-fluorescence spectrometry for the determination of molybdenum and tungsten in ion-exchange resins. The dried resin is milled with sand, binder, and an internal-standard mixture before being briquetted. Niobium and zinc are used as the internal standards for molybdenum and tungsten respectively. Intensity measurements are made with the gold anode tube. Corrections are made for the interference of the Mo Kα analytical line on the background intensities used for the Mo Kα and Nb Kα lines. The precision of the analysis for molybdenum ranges from a relative standard deviation 0,02 at 5 mg/g to 0.045 at 55μg/g; for tungsten, the relative standard deviation ranges from 0,04 at 5 mg/g to 0,055 at 55μg/g. The limits of determination in the original resin sample were found to be 40μg/g for molybdenum and 80μg/g for tungsten. The laboratory method is given in an appendix

  5. Disruption of the hydrogen bonding network determines the pH-induced non-fluorescent state of the fluorescent protein ZsYellow by protonation of Glu221.

    Bae, Ji-Eun; Kim, In Jung; Nam, Ki Hyun

    2017-11-04

    Many fluorescent proteins (FPs) exhibit fluorescence quenching at a low pH. This pH-induced non-fluorescent state of an FP serves as a useful indicator of the cellular pH. ZsYellow is widely used as an optical marker in molecular biology, but its pH-induced non-fluorescent state has not been characterized. Here, we report the pH-dependent spectral properties of ZsYellow, which exhibited the pH-induced non-fluorescence state at a pH below 4.0. We determined the crystal structures of ZsYellow at pH 3.5 (non-fluorescence state) and 8.0 (fluorescence state), which revealed the cis-configuration of the chromophore without pH-induced isomerization. In the non-fluorescence state, Arg95, which is involved in stabilization of the exited state of the chromophore, was found to more loosely interact with the carbonyl oxygen atom of the chromophore when compared to the interaction at pH 8.0. In the fluorescence state, Glu221, which is involved in the hydrogen bonding network around the chromophore, stably interacted with Gln42 and His202. By contrast, in the non-fluorescence state, the protonated conserved Glu221 residue exhibited a large conformational change and was separated from His202 by 5.46 Å, resulting in breakdown of the hydrogen bond network. Our results provide insight into the critical role of the conserved Glu221 residue for generating the pH-induced non-fluorescent state. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Handbook of practical X-ray fluorescence analysis

    Beckhoff, B.; Wedell, R.; Wolff, H.

    2006-01-01

    X-ray fluorescence analysis (XRF) is a reliable multi-elemental and nondestructive analytical method widely used in research and industrial applications. This practical handbook provides self-contained modules featuring XRF instrumentation, quantification methods, and most of the current applications. The broad spectrum of topics is due to the efforts of a large number of authors from a variety of different types of institutions such as universities, research institutes, and companies. The book gives a survey of the theoretical fundamentals, analytical instrumentation, software for data processing, various excitation regimes including gracing incidents and microfocus measurements, quantitative analysis, applications in routine and micro analysis, mineralogy, biology, medicine, criminal investigations, archeology, metallurgy, abrasion, microelectronics, environmental air and water analysis. It gives the basic knowledge on this technique, information on analytical equipment and guides the reader to the various applications. This practical handbook is intended as a resource for graduate students, research scientists, and industrial users. (orig.)

  7. Handbook of practical X-ray fluorescence analysis

    Beckhoff, B. [Physikalisch-Technische Bundesanstalt, Berlin (Germany). X-ray Spectrometry; Kanngiesser, B. [Technische Univ. Berlin (Germany). Inst. fuer Atomare Physik und Fachdidaktik; Langhoff, N. [IfG-Institute for Scientific Instruments GmbH, Berlin (Germany); Wedell, R.; Wolff, H. (eds.) [Institut fuer Angewandte Photonik e.V., Berlin (Germany)

    2006-07-01

    X-ray fluorescence analysis (XRF) is a reliable multi-elemental and nondestructive analytical method widely used in research and industrial applications. This practical handbook provides self-contained modules featuring XRF instrumentation, quantification methods, and most of the current applications. The broad spectrum of topics is due to the efforts of a large number of authors from a variety of different types of institutions such as universities, research institutes, and companies. The book gives a survey of the theoretical fundamentals, analytical instrumentation, software for data processing, various excitation regimes including gracing incidents and microfocus measurements, quantitative analysis, applications in routine and micro analysis, mineralogy, biology, medicine, criminal investigations, archeology, metallurgy, abrasion, microelectronics, environmental air and water analysis. It gives the basic knowledge on this technique, information on analytical equipment and guides the reader to the various applications. This practical handbook is intended as a resource for graduate students, research scientists, and industrial users. (orig.)

  8. Total-reflection X-ray fluorescence analysis of Austrian wine

    Gruber, X. [Atominstitut der Osterreichischen Universitaeten, 1020 Vienna (Austria); Kregsamer, P. [Atominstitut der Osterreichischen Universitaeten, 1020 Vienna (Austria); Wobrauschek, P. [Atominstitut der Osterreichischen Universitaeten, 1020 Vienna (Austria); Streli, C. [Atominstitut der Osterreichischen Universitaeten, 1020 Vienna (Austria)]. E-mail: streli@ati.ac.at

    2006-11-15

    The concentration of major, minor and trace elements in Austrian wine was determined by total-reflection X-ray fluorescence using gallium as internal standard. A multi-elemental analysis was possible by pipetting 6 {mu}l of wine directly on the reflector and drying. Total-reflection X-ray fluorescence analysis was performed with Atomika EXTRA II A (Cameca) X-rays from a Mo tube with a high-energy cut-off at 20 keV in total-reflection geometry. The results showed that it was possible to identify only by the elemental analysis as fingerprint the vineyards and year of vintage among 11 different wines.

  9. Total-reflection X-ray fluorescence analysis of Austrian wine

    Gruber, X.; Kregsamer, P.; Wobrauschek, P.; Streli, C.

    2006-01-01

    The concentration of major, minor and trace elements in Austrian wine was determined by total-reflection X-ray fluorescence using gallium as internal standard. A multi-elemental analysis was possible by pipetting 6 μl of wine directly on the reflector and drying. Total-reflection X-ray fluorescence analysis was performed with Atomika EXTRA II A (Cameca) X-rays from a Mo tube with a high-energy cut-off at 20 keV in total-reflection geometry. The results showed that it was possible to identify only by the elemental analysis as fingerprint the vineyards and year of vintage among 11 different wines

  10. X-ray fluorescence analysis of welding fume particles

    Carsey, T.P.

    1982-01-01

    A commercial standard filter set and two laboratory-made standard filter sets are compared via the analysis of generated welding fume samples by X-ray fluorescence. The latter standards are made by (1) hydrophobic-edge membrane filters spiked with prepared metal ion solutions, and (2) filters through which a dispersion of metal oxide powder in isopropanol has been drawn. The results are presented in table form. Precision (Pre) is the relative standard deviation of the six samples. Four main conclusions are enumerated

  11. Quantification procedures in micro X-ray fluorescence analysis

    Kanngiesser, Birgit

    2003-01-01

    For the quantification in micro X-ray fluorescence analysis standardfree quantification procedures have become especially important. An introduction to the basic concepts of these quantification procedures is given, followed by a short survey of the procedures which are available now and what kind of experimental situations and analytical problems are addressed. The last point is extended by the description of an own development for the fundamental parameter method, which renders the inclusion of nonparallel beam geometries possible. Finally, open problems for the quantification procedures are discussed

  12. Determination of Cu, Cr, and As in preserved wood (Eucalyptus sp.) using x-ray fluorescent spectrometry techniques

    Sergio Matias Pereira Junior; Vera Akiko Maihara; Edson Goncalves Moreira; Vera Lucia Ribeiro Salvador; Ivone Mulako Sato

    2016-01-01

    Energy dispersive (EDXRF) and Portable (PXRF) X-ray fluorescence techniques are proposed for wood treatment control process and wood waste assortment. In this study, different retentions of chromated copper arsenate preservative were applied to Eucalyptus sp. sapwood samples. Cu, Cr and As were determined by XRF techniques in treated sapwood massive blocks and treated sapwood sawdust samples were analyzed by FAAS spectrometry (Flame Atomic Absorption) and INAA (Instrumental Neutron Activation Analysis). Cu, Cr and As mean values, obtained by FAASS and INAA, showed to be statically equal; however, XRF analysis showed considerable deviations, presenting the absorption and the enhancement effects in analytical lines. (author)

  13. Integrated luminometer for the determination of trace metals in seawater using fluorescence, phosphorescence and chemiluminescence detection

    Worsfold, P. J.; Achterberg, E. P.; Bowie, A. R.; Cannizzaro, V.; Charles, S.; Costa, J. M.; Dubois, F.; Pereiro, R.; San Vicente, B.; Sanz-Medel, A.; Vandeloise, R.; Donckt, E. Vander; Wollast, P.; Yunus, S.

    2002-01-01

    The paper describes an integrated luminometer able to perform fluorescence (FL), room temperature phosphorescence (RTP) and chemiluminescence (CL) measurements on seawater samples. The technical details of the instrumentation are presented together with flow injection (FI) manifolds for the determination of cadmium and zinc (by FL), lead (RTP) and cobalt (CL). The analytical figures of merit are given for each mainfold and results are presented for the determination of the four trace metals i...

  14. Determination of low concentrations of thorium in geological materials by X-ray fluorescence

    Roca, M.; Bayon, A.

    1981-01-01

    An X-ray fluorescence method for the determination of thorium in geological samples down to 2 ppm ThO 2 has been developed. To achieve this determination limit an exposed area of the sample 42.5 mm in diameter is used, working with a molybdenum target tube operated at 90 kV and 30 m A. Corrections for background and line interference of the Rb Kα radiation have been carefully considered and empirical correction coefficients calculated. (Author) 3 refs

  15. Quantitative determination of uranium in organic solution by X-ray fluorescence

    Leyt, D.V. de; Colangelo, C.H.

    1987-01-01

    An X-ray fluorescent method for the determination of uranium in tributilphosphate-kerosene-nitriacid solution has been developed. Chemical properties of the matrix elements were studied in order to select a convenient procedure to determine samples and standards on the same way. The method avoids the destruction of the organic material and has proved to be very useful for the fast control of uranium concentration. (Author) [es

  16. An X-ray fluorescence method for the determination of metals thicknesses

    Vazquez, Cristina; Leyt, D.V. de; Riveros, J.A.

    1987-01-01

    An absolute method for the determination of the thickness of a metal film deposited on a metallic substrate is described. The method is based on the measurement of fluorescent intensity ratios for two lines from the substrate element. Additionally, the proposed method can be employed to determine the density of the deposited material or the incident angle of primary radiation and take off angle, if the metal film thickness is known. (Author) [es

  17. Determination of trace elements in tea by wavelength dispersive X-ray fluorescence spectroscopy

    Gong Chunhui; Zeng Guoqiang; Ge Liangquan; Li Jun; Wen Ziqiang

    2013-01-01

    Background: Measuring trace elements in tea can determine its nutritional value, verify the authenticity and place of origin, and detect the poisonous and harmful elements remaining in tea due to the application of chemical fertilizers and pesticides. Purpose: In order to reduce the time for sample preparation and the costs of equipment maintenance, wavelength dispersive X-ray fluorescence (WDXRF) spectroscopy was used to determine the trace elements in tea which is rapid, non-destructive and accurate. The contents of more than 20 elements can be measured simultaneously. Methods: Sample pieces were made by the sample preparation method of boric acid rebasing. To avoid the exogenous environmental pollution subjected in the growth of tea, we removed the residual dust of the tea by cleaning it. According to the principle that the standard samples should be similar types with the samples to be analyzed to select standard samples. The curves were built by SuperQ, which contained compiling the measurement conditions, establishing the measurement conditions, checking the angles, determining the measurement times, checking PHD and adding the contents and the names of sample pieces. The accuracy of the method can be obtained by comparing the measured values with the trace element contents of standard samples. The contents of trace elements in tea determined by WDXRF can be used to classify the tea attribution and the tea species through cluster analysis of SPSS software. Results: (1) The results show that the biggest relative standard deviation is 0.43% of Pb, and the precision is very good. (2) Five kinds of tea are taken separately in Fujian and Yunnan, measured three times with the established working curves. And tree diagram of cluster analysis can be obtained with SPSS software to analyze the measured average values with cluster analysis, coupling method between groups and Minkowski distance measurement techniques. It can be seen that in the tree diagram, when the

  18. A step towards standardization: A method for end-point titer determination by fluorescence index of an automated microscope. End-point titer determination by fluorescence index.

    Carbone, Teresa; Gilio, Michele; Padula, Maria Carmela; Tramontano, Giuseppina; D'Angelo, Salvatore; Pafundi, Vito

    2018-05-01

    Indirect Immunofluorescence (IIF) is widely considered the Gold Standard for Antinuclear Antibody (ANA) screening. However, the high inter-reader variability remains the major disadvantage associated with ANA testing and the main reason for the increasing demand of the computer-aided immunofluorescence microscope. Previous studies proposed the quantification of the fluorescence intensity as an alternative for the classical end-point titer evaluation. However, the different distribution of bright/dark light linked to the nature of the self-antigen and its location in the cells result in different mean fluorescence intensities. The aim of the present study was to correlate Fluorescence Index (F.I.) with end-point titers for each well-defined ANA pattern. Routine serum samples were screened for ANA testing on HEp-2000 cells using Immuno Concepts Image Navigator System, and positive samples were serially diluted to assign the end-point titer. A comparison between F.I. and end-point titers related to 10 different staining patterns was made. According to our analysis, good technical performance of F.I. (97% sensitivity and 94% specificity) was found. A significant correlation between quantitative reading of F.I. and end-point titer groups was observed using Spearman's test and regression analysis. A conversion scale of F.I. in end-point titers for each recognized ANA-pattern was obtained. The Image Navigator offers the opportunity to improve worldwide harmonization of ANA test results. In particular, digital F.I. allows quantifying ANA titers by using just one sample dilution. It could represent a valuable support for the routine laboratory and an effective tool to reduce inter- and intra-laboratory variability. Copyright © 2018. Published by Elsevier B.V.

  19. Determination of fission products in irradiated fuel by X-ray fluorescence

    Mogensen, M.; Als-Nielsen, J.; Hessel Andersen, N.

    1986-08-01

    X-ray fluorescence is a well established analytical tool for measuring elemental composition of fairly large (approximately 5 cm 2 ) ''cold'' samples. A version of this technique has been developed for analysis of radial distribution of fission products Xe, Cs and Ba in irradiated UO 2 fuel samples. About 0.1 mm thin slices of fuel pellets (full cross sections) are irradiated by 50 keV X-rays. The intensity of the Xe (Cs, Ba) K α fluorescence radiation generated is measured by means of a Ge detector fitted with a collimator. The slit is 0.5 mm wide in the scanning direction and 2 mm long. The measured Xe K α X-ray intensities are converted to absolute concentrations by comparing to the intensity from a Xe gas standard. In the case of Cs and Ba solid standards may be used. The X-ray fluorescence analysis is compared to other techniques used to obtain radial fission product profiles. It is shown how a combination of X-ray fluorescence and electron probe micro analysis is able to reveal the amount of Xe in the grain boundary porosities. (author)

  20. Determination of the botanical origin of honey by front-face synchronous fluorescence spectroscopy.

    Lenhardt, Lea; Zeković, Ivana; Dramićanin, Tatjana; Dramićanin, Miroslav D; Bro, Rasmus

    2014-01-01

    Front-face synchronous fluorescence spectroscopy combined with chemometrics is used to classify honey samples according to their botanical origin. Synchronous fluorescence spectra of three monofloral (linden, sunflower, and acacia), polyfloral (meadow mix), and fake (fake acacia and linden) honey types (109 samples) were collected in an excitation range of 240-500 nm for synchronous wavelength intervals of 30-300 nm. Chemometric analysis of the gathered data included principal component analysis and partial least squares discriminant analysis. Mean cross-validated classification errors of 0.2 and 4.8% were found for a model that accounts only for monofloral samples and for a model that includes both the monofloral and polyfloral groups, respectively. The results demonstrate that single synchronous fluorescence spectra of different honeys differ significantly because of their distinct physical and chemical characteristics and provide sufficient data for the clear differentiation among honey groups. The spectra of fake honey samples showed pronounced differences from those of genuine honey, and these samples are easily recognized on the basis of their synchronous fluorescence spectra. The study demonstrated that this method is a valuable and promising technique for honey authentication.

  1. Quantitative analysis by computer controlled X-ray fluorescence spectrometer

    Balasubramanian, T.V.; Angelo, P.C.

    1981-01-01

    X-ray fluorescence spectroscopy has become a widely accepted method in the metallurgical field for analysis of both minor and major elements. As encountered in many other analytical techniques, the problem of matrix effect generally known as the interelemental effects is to be dealt with effectively in order to make the analysis accurate. There are several methods by which the effects of matrix on the analyte are minimised or corrected for and the mathematical correction is one among them. In this method the characteristic secondary X-ray intensities are measured from standard samples and correction coefficients. If any, for interelemental effects are evaluated by mathematical calculations. This paper describes attempts to evaluate the correction coefficients for interelemental effects by multiple linear regression programmes using a computer for the quantitative analysis of stainless steel and a nickel base cast alloy. The quantitative results obtained using this method for a standard stainless steel sample are compared with the given certified values. (author)

  2. Determination of poorly fluorescent carbamate pesticides in water, bendiocarb and promecarb, using cyclodextrin nanocavities and related media

    Pacioni, Natalia L.; Veglia, Alicia V.

    2007-01-01

    The effect of native cyclodextrins (α, β, or γCD with six, seven and eight glucose units, respectively), hydroxypropyl-β-cyclodextrin (HPCD), chitosan (CHT) and glucose in water solution or water with n-propylamine (PA) as co-solvent upon the UV-vis and fluorescence properties of poorly fluorescent N-methyl carbamates pesticides (C) as bendiocarb (2,2-dimethyl-1,3-benzodioxol-4-ol methylcarbamate, BC) and promecarb (3-methyl-5-(1-methylethyl)phenol methylcarbame, PC) was examined. Fluorescent enhancement was found for both substrates with all CDs in water or PA-water except from PC with αCD. The addition of CHT increases the fluorescence of BC but decreases the fluorescence of PC, and glucose addition gives in both cases no spectral changes. Host-guest interaction was clearly determined by fluorescence enhancement with βCD and HPCD with a 1:1 stoichiometry for the complexes (C:CD). The values obtained for the association constants (K A , M -1 ) were (6 ± 2) x 10 2 and (2.3 ± 0.3) x 10 2 for BC:βCD and BC:HPCD complexes, respectively. For PC:βCD and PC:HPCD the values of K A were (19 ± 2) x 10 2 and (21 ± 2) x 10 2 , respectively. The ratio of the fluorescence quantum yields for the bound and free substrates (φ CCD /φ C ) was in the range 1.74-3.8. The limits of detection (L D , μg mL -1 ) for the best conditions were (0.57 ± 0.02) for BC with HPCD and (0.091 ± 0.002) for PC with βCD in water. Application to the analysis in pesticide spiked samples of tap water and fruit yields satisfactory apparent recoveries (84-114%), and for the extraction procedure in fruits and a commercial formulation, recoveries were of 81-98% and 104%, respectively. The method is rapid, simple, direct, sensitive and useful for pesticide analysis

  3. Determination of poorly fluorescent carbamate pesticides in water, bendiocarb and promecarb, using cyclodextrin nanocavities and related media

    Pacioni, Natalia L. [Instituto de Investigaciones en Fisico Quimica de Cordoba (INFIQC), Departamento de Quimica Organica, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba, Ciudad Universitaria, 5000 Cordoba (Argentina); Veglia, Alicia V. [Instituto de Investigaciones en Fisico Quimica de Cordoba (INFIQC), Departamento de Quimica Organica, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba, Ciudad Universitaria, 5000 Cordoba (Argentina)]. E-mail: aveglia@mail.fcq.unc.edu.ar

    2007-01-30

    The effect of native cyclodextrins ({alpha}, {beta}, or {gamma}CD with six, seven and eight glucose units, respectively), hydroxypropyl-{beta}-cyclodextrin (HPCD), chitosan (CHT) and glucose in water solution or water with n-propylamine (PA) as co-solvent upon the UV-vis and fluorescence properties of poorly fluorescent N-methyl carbamates pesticides (C) as bendiocarb (2,2-dimethyl-1,3-benzodioxol-4-ol methylcarbamate, BC) and promecarb (3-methyl-5-(1-methylethyl)phenol methylcarbame, PC) was examined. Fluorescent enhancement was found for both substrates with all CDs in water or PA-water except from PC with {alpha}CD. The addition of CHT increases the fluorescence of BC but decreases the fluorescence of PC, and glucose addition gives in both cases no spectral changes. Host-guest interaction was clearly determined by fluorescence enhancement with {beta}CD and HPCD with a 1:1 stoichiometry for the complexes (C:CD). The values obtained for the association constants (K {sub A}, M{sup -1}) were (6 {+-} 2) x 10{sup 2} and (2.3 {+-} 0.3) x 10{sup 2} for BC:{beta}CD and BC:HPCD complexes, respectively. For PC:{beta}CD and PC:HPCD the values of K {sub A} were (19 {+-} 2) x 10{sup 2} and (21 {+-} 2) x 10{sup 2}, respectively. The ratio of the fluorescence quantum yields for the bound and free substrates ({phi} {sup CCD}/{phi} {sup C}) was in the range 1.74-3.8. The limits of detection (L {sub D}, {mu}g mL{sup -1}) for the best conditions were (0.57 {+-} 0.02) for BC with HPCD and (0.091 {+-} 0.002) for PC with {beta}CD in water. Application to the analysis in pesticide spiked samples of tap water and fruit yields satisfactory apparent recoveries (84-114%), and for the extraction procedure in fruits and a commercial formulation, recoveries were of 81-98% and 104%, respectively. The method is rapid, simple, direct, sensitive and useful for pesticide analysis.

  4. Determination of iron and titanium in kaolins by the method of non-dispersive X-ray fluorescence

    Bialy, N.; Kierzek, J.; Parus, J.

    1976-01-01

    The possibility of application of the radioactive source excited X-ray fluorescence analysis for titanium and iron determination in kaolins to the routine test of the refinement process has been studied. The iron content can be determined with a simple counting system using a single-channel pulse height analyser, argon filled proportional counter and 109 Cd source of 3 mCi for the excitation of K Fe rays. The samples were analyzed both as pellets and powders. The iron content ranged from 0.2-2.5% and titanium from 0.1-0.64%. The best values of precision and determination limit have been achieved for iron with 238 Pu and for titanium with 55 Fe. The precision and accuracy of the X-ray fluorescence method of iron and titanium determination in kaolins are comparable to those of the chemical method. For the simultaneous iron and titanium determination in the discussed region of concentration it is the most advantageous to use the plutonium source with the activity of several tens of mCi and Si(Li) detector with a moderate resolution (250-300 eV for 5.9 keV). The time of the analysis carried out by the described method is several times shorter than the chemical method. The apparatus used in this method is relatively simple, the sample preparation does not require any chemical treatment and the cost of labour of the sample preparation is minimal. (T.G.)

  5. Fluorescence spectroscopy for the detection of potentially malignant disorders of the oral cavity: analysis of 30 cases

    Francisco, A L N; Correr, W R; Kurachi, C; Azevedo, L H; Galletta, V K; Pinto, C A L; Kowalski, L P

    2014-01-01

    Oral cancer is a major health problem worldwide and although early diagnosis of potentially malignant and malignant diseases is associated with better treatment results, a large number of cancers are initially misdiagnosed, with unfortunate consequences for long-term survival. Fluorescence spectroscopy is a noninvasive modality of diagnostic approach using induced fluorescence emission in tumors that can improve diagnostic accuracy. The objective of this study was to determine the ability to discriminate between normal oral mucosa and potentially malignant disorders by fluorescence spectroscopy. Fluorescence investigation under 408 and 532 nm excitation wavelengths was performed on 60 subjects, 30 with potentially malignant disorders and 30 volunteers with normal mucosa. Data was analyzed to correlate fluorescence patterns with clinical and histopathological diagnostics. Fluorescence spectroscopy used as a point measurement technique resulted in a great variety of spectral information. In a qualitative analysis of the fluorescence spectral characteristics of each type of injury evaluated, it was possible to discriminate between normal and abnormal oral mucosa. The results show the potential use of fluorescence spectroscopy for an improved discrimination of oral disorders. (paper)

  6. Determination of the cathode fall voltage in fluorescent lamps by measurement of the operating voltage

    Hilscher, A.

    2002-01-01

    A new method for the determination of the cathode fall voltage of fluorescent lamps is shown. The cathode fall voltage can be determined by measurement of the lamp operating voltage at constant lamp wall temperature, constant discharge current and variation of the electrode heating current. Commercial lamps, which do not need to be specially prepared, can be used for the measurement. The results show good correlation to other measurements of the cathode fall voltage at various discharge currents by means of capacitive coupling. The measured values of the cathode fall voltage are used for determining the minimum, target and maximum setting of the sum of the squares of the pin currents of one electrode (the so-called SOS value) as a function of the discharge current in fluorescent lamp dimming. (author)

  7. Determination of selenium via the fluorescence quenching effect of selenium on hemoglobin-catalyzed peroxidative reaction.

    Chen, Ya-Hong; Zhang, Ya-Nan; Tian, Feng-Shou

    2015-05-01

    A new method for the determination of selenium based on its fluorescence quenching on the hemoglobin-catalyzed reaction of H2 O2 and l-tyrosine has been established. The effect of pH, foreign ions and the optimization of variables on the determination of selenium was examined. The calibration curve was found to be linear between the fluorescence quenching (F0 /F) and the concentration of selenium within the range of 0.16-4.00 µg/mL. The detection limit was 1.96 ng/mL and the relative standard deviation was 3.14%. This method can be used for the determination of selenium in Se-enriched garlic bulbs with satisfactory results. Copyright © 2014 John Wiley & Sons, Ltd.

  8. ZnSe quantum dots based fluorescence quenching method for determination of paeoniflorin

    Chen, Zhi [Center of Analysis, Guangdong Medical College, Dongguan 523808 (China); School of Chinese Herbal Medicine, Guangzhou University of Chinese Medicine, Guangzhou 510006 (China); Chen, Jiayi; Liang, Qiaowen [School of Chinese Herbal Medicine, Guangzhou University of Chinese Medicine, Guangzhou 510006 (China); Wu, Dudu [Center of Analysis, Guangdong Medical College, Dongguan 523808 (China); Zeng, Yuaner, E-mail: zengyuaner@126.com [School of Chinese Herbal Medicine, Guangzhou University of Chinese Medicine, Guangzhou 510006 (China); Jiang, Bin, E-mail: gzjiangbin@hotmail.com [School of Chinese Herbal Medicine, Guangzhou University of Chinese Medicine, Guangzhou 510006 (China)

    2014-01-15

    Water soluble ZnSe quantum dots (QDs) modified by mercaptoacetic acid (MAA) were used to determinate paeoniflorin in aqueous solutions by the fluorescence spectroscopic technique. The results showed that the fluorescence of the modified ZnSe QDs could be quenched by paeoniflorin effectively in physiological buffer solution. The optimum fluorescence intensity was found to be at incubation time 10 min, pH 7.0 and temperature 25 °C. Under the optimal conditions, the detection limit of paeoniflorin was 7.30×10{sup −7} mol L{sup −1}. Moreover, the quenching mechanism was discussed to be a static quenching procedure, which was proved by quenching rate constant K{sub q} (1.02×10{sup 13} L mol{sup −1} s{sup −1}). -- Highlights: • The fluorescence intensity of ZnSe QDs could be quenched by paeoniflorin. • Foreign substance showed insignificant effect for determination of paeoniflorin. • The quenching mechanism was discussed to be a static quenching procedure.

  9. ZnSe quantum dots based fluorescence quenching method for determination of paeoniflorin

    Chen, Zhi; Chen, Jiayi; Liang, Qiaowen; Wu, Dudu; Zeng, Yuaner; Jiang, Bin

    2014-01-01

    Water soluble ZnSe quantum dots (QDs) modified by mercaptoacetic acid (MAA) were used to determinate paeoniflorin in aqueous solutions by the fluorescence spectroscopic technique. The results showed that the fluorescence of the modified ZnSe QDs could be quenched by paeoniflorin effectively in physiological buffer solution. The optimum fluorescence intensity was found to be at incubation time 10 min, pH 7.0 and temperature 25 °C. Under the optimal conditions, the detection limit of paeoniflorin was 7.30×10 −7 mol L −1 . Moreover, the quenching mechanism was discussed to be a static quenching procedure, which was proved by quenching rate constant K q (1.02×10 13 L mol −1 s −1 ). -- Highlights: • The fluorescence intensity of ZnSe QDs could be quenched by paeoniflorin. • Foreign substance showed insignificant effect for determination of paeoniflorin. • The quenching mechanism was discussed to be a static quenching procedure

  10. Determination of ammonium on an integrated microchip with LED-induced fluorescence detection.

    Xue, Shuhua; Uchiyama, Katsumi; Li, Hai-Fang

    2012-01-01

    A simply fabricated microfluidic device integrated with a fluorescence detection system has been developed for on-line determination of ammonium in aqueous samples. A 365-nm light-emitting diode (LED) as an excitation source and a minor band pass filter were mounted into a polydimethylsiloxane (PDMS)-based microchip for the purpose of miniaturization of the entire analytical system. The ammonium sample reacted with o-phthaldialdehyde (OPA) on-chip with sodium sulfite as reducing reagent to produce a fluorescent isoindole derivative, which can emit fluorescence signal at about 425 nm when excited at 365 nm. Effects of pH, flow rate of solutions, concentrations of OPA-reagent, phosphate and sulfite salt were investigated. The calibration curve of ammonium in the range of 0.018-1.8 microg/mL showed a good linear relationship with R2 = 0.9985, and the detection limit was (S/N = 3) 3.6 x 10(-4) microg/mL. The relative standard deviation was 2.8% (n = 11) by calculating at 0.18 microg/mL ammonium for repeated detection. The system was applied to determine the ammonium concentration in rain and river waters, even extent to other analytes fluorescence detection by the presented device.

  11. Compositional analysis of steels by x-ray fluorescence spectrometry

    Kutty, K.V.G.; Rajagopalan, S.; Ananthakrishnan, S.K.; Asuvatharaman, R.

    1988-01-01

    The x-ray fluorescence spectrometric method of determining Ni, Cr, Mn, Mo, T i, Si and Co in austenitic, ferritic, titanium-stabilised and low alloy steels is described. Samples in the bulk solid form (25-50 mm diameter and upto 50 mm height) or very small samples having a flat surface at least 5 mm in diameter are analysed as received after a brief surface treatment. The complex matrix effects affecting the determination of the various elements are discussed. The direct calibration method as well as the mathematical method of empirical coefficients of overcoming the matrix effects is described. The precision and accuracy of the analyses are discussed. (author). 10 refs

  12. Multielemental analysis of osseous remains by x-ray fluorescence to determine types of diets from the Cultura Lima (II B.C. - VIII A.C); Analisis multielemental de restos oseos por fluorescencia de rayos-x para la reconstruccion de dietas del periodo temprano en la Cultura de Lima

    Montalvo B, A

    1998-12-31

    The multielemental analysis of 29 human bone samples and sediments from the Lima Culture (III c. BC to IX c. AC) were analyzed by x-ray fluorescence technique with Cd-109 excitation source Si(Li) detector, Canberra associated electronic and PCA-II nucleus multichannel card, in order to determine to determine the diet type of these antique inhabitant. The elements found in bone rests were Ca, Sr, Zn, Mn, Fe, Ni, Cu, Rb, Zn and Pb, and As in one of the clavicles. In sediment samples we obtained a major quantity of elements. According to the Sr an Zn obtained values in osseous rest and the developed regression model, we can conclude that the ancient inhabitants of Lima Culture had an omnivorous feeding with a carnivore tendency due to its geographic location. (author). 35 refs., 9 figs., 10 tabs., 6 ills.

  13. Determination of Europium by fluorescence using pyrrolidinium based task specific ionic liquid

    Kumar, Satendra; Gayan, Siuli Maji; Sankaran, K.

    2012-01-01

    Determination of lanthanides using fluorescence is a major challenge in aqueous medium due to their poor molar absorptivities and low quantum yield. To overcome these problems, ligand sensitized fluorescence has been widely used for trace level detection of lanthanides in solutions. Recently, ionic liquid a non aqueous medium has been used to observe the fluorescence of lanthanides. In this work we have used pyrrolidinium based ionic liquid for the study of europium fluorescence. The ionic liquid (bmpyr)(BA) was prepared using the metathesis reaction involving 1-butyl,1-methyl pyrrolidinium chloride (bmpyr)(CI). (bmpyr)(Cl) crystals and silver benzoate were added according to their mole equivalents in methanol and stirred for 4 hrs. The filtrate was concentrated using a rotary evaporator, dried for 10 h at room temperature, and then for 40 h at 105℃under reduced pressure. This results in a white crystalline hygroscopic solid which was characterized by FT-lR spectroscopy. The yield of the product was ∼ 95%. Butyl-1, methyl pyrrolidinium bis(trifluoromethanesulfonyl)amide (bmpyr)(TF 2 N) is used for dissolve and dilute (bmpyr)(BA) and fluorescence and life time of Eu 3+ were obtained. For the concentration of Eu 3+ used in this study (2x10 -7 M), the optimum concentration of the sensitizing ionic liquid was found to be 10 -4 M. An enhancement factor of about 32000 was found in this ionic liquid compare to aqueous medium. Fluorescence life time of europium in this ionic liquid is 1100 μs which is ten times more than the life time of europium in aqueous medium (110 μs), indicating a reduction in the rates of non-radiative processes which was provided by the ionic liquid. This study leads to detection of europium in ppb level. (author)

  14. Rapid analysis of molybdenum contents in molybdenum master alloys by X-ray fluorescence technique

    Tongkong, P.

    1985-01-01

    Determination of molybdenum contents in molybdenum master alloy had been performed using energy dispersive x-ray fluorescence (EDX) technique where analysis were made via standard additions and calibration curves. Comparison of EDX technique with other analyzing techniques, i.e., wavelength dispersive x-ray fluorescence, neutron activation analysis and inductive coupled plasma spectrometry, showed consistency in the results. This technique was found to yield reliable results when molybdenum contents in master alloys were in the range of 13 to 50 percent using HPGe detector or proportional counter. When the required error was set at 1%, the minimum analyzing time was found to be 30 and 60 seconds for Fe-Mo master alloys with molybdenum content of 13.54 and 49.09 percent respectively. For Al-Mo master alloys, the minimum times required were 120 and 300 seconds with molybdenum content of 15.22 and 47.26 percent respectively

  15. Hybrid Microfluidic Platform for Multifactorial Analysis Based on Electrical Impedance, Refractometry, Optical Absorption and Fluorescence

    Fábio M. Pereira

    2016-10-01

    Full Text Available This paper describes the development of a novel microfluidic platform for multifactorial analysis integrating four label-free detection methods: electrical impedance, refractometry, optical absorption and fluorescence. We present the rationale for the design and the details of the microfabrication of this multifactorial hybrid microfluidic chip. The structure of the platform consists of a three-dimensionally patterned polydimethylsiloxane top part attached to a bottom SU-8 epoxy-based negative photoresist part, where microelectrodes and optical fibers are incorporated to enable impedance and optical analysis. As a proof of concept, the chip functions have been tested and explored, enabling a diversity of applications: (i impedance-based identification of the size of micro beads, as well as counting and distinguishing of erythrocytes by their volume or membrane properties; (ii simultaneous determination of the refractive index and optical absorption properties of solutions; and (iii fluorescence-based bead counting.

  16. Photocured thiol-ene based optical fluorescence sensor for determination of gold(III)

    Çubuk, Soner, E-mail: sonercubuk@marmara.edu.tr; Kahraman, Memet Vezir; Yetimoğlu, Ece Kök; Kenan, Sibel

    2014-02-17

    Graphical abstract: -- Highlights: •Photopolymerized fluorescence sensor for Au(III) analysis has been developed. •Preparation of polymeric sensor is simple and quick. •Fluorescence sensor used for analysis of Au(III) in real samples. -- Abstract: This study describes the preparation and the characterization of a new thiol-ene based polymeric fluorescence sensor by photo initiated polymerization of trimethylolpropane tris(3-mercaptopropionate), 2-hydroxyethylacrylate, and 2,4,6-triallyloxy-1,3,5-triazine which are used as monomers and also a photo initiator (2,2-dimethoxy-2-phenylacetophenone) for its usage as optical sensor for gold ions. The thiol-ene based polymeric membrane sensor was characterized by using attenuated total reflectance-fourier transform infrared spectroscopy (ATR-FTIR) and scanning electron microscopy (SEM). The response characteristics of the sensors including dynamic range, pH effect, response time, and the effect of foreign ions were investigated. Fluorescence spectra showed that the excitation/emission maxima of the membrane were at 379/425 nm, respectively.

  17. Photocured thiol-ene based optical fluorescence sensor for determination of gold(III)

    Çubuk, Soner; Kahraman, Memet Vezir; Yetimoğlu, Ece Kök; Kenan, Sibel

    2014-01-01

    Graphical abstract: -- Highlights: •Photopolymerized fluorescence sensor for Au(III) analysis has been developed. •Preparation of polymeric sensor is simple and quick. •Fluorescence sensor used for analysis of Au(III) in real samples. -- Abstract: This study describes the preparation and the characterization of a new thiol-ene based polymeric fluorescence sensor by photo initiated polymerization of trimethylolpropane tris(3-mercaptopropionate), 2-hydroxyethylacrylate, and 2,4,6-triallyloxy-1,3,5-triazine which are used as monomers and also a photo initiator (2,2-dimethoxy-2-phenylacetophenone) for its usage as optical sensor for gold ions. The thiol-ene based polymeric membrane sensor was characterized by using attenuated total reflectance-fourier transform infrared spectroscopy (ATR-FTIR) and scanning electron microscopy (SEM). The response characteristics of the sensors including dynamic range, pH effect, response time, and the effect of foreign ions were investigated. Fluorescence spectra showed that the excitation/emission maxima of the membrane were at 379/425 nm, respectively

  18. Determination of metals in air samples using X-Ray fluorescence associated the APDC preconcentration technique

    Nardes, Raysa C.; Santos, Ramon S.; Sanches, Francis A.C.R.A.; Gama Filho, Hamilton S.; Oliveira, Davi F.; Anjos, Marcelino J., E-mail: rc.nardes@gmail.com, E-mail: ramonziosp@yahoo.com.br, E-mail: francissanches@gmail.com, E-mail: hamiltongamafilho@hotmail.com, E-mail: davi.oliveira@uerj.br, E-mail: marcelin@uerj.br [Universidade do Estado do Rio de Janeiro (UERJ), Rio de Janeiro, RJ (Brazil). Instituto de Fisica. Departamento de Fisica Aplicada e Termodinamica

    2015-07-01

    Air pollution has become one of the leading quality degradation factors of life for people in large urban centers. Studies indicate that the suspended particulate matter in the atmosphere is directly associated with risks to public health, in addition, it can cause damage to fauna, flora and public / cultural patrimonies. The inhalable particulate materials can cause the emergence and / or worsening of chronic diseases related to respiratory system and other diseases, such as reduced physical strength. In this study, we propose a new method to measure the concentration of total suspended particulate matter (TSP) in the air using an impinger as an air cleaning apparatus, preconcentration with APDC and Total Reflection X-ray Fluorescence technique (TXRF) to analyze the heavy metals present in the air. The samples were collected from five random points in the city of Rio de Janeiro/Brazil. Analyses of TXRF were performed at the Brazilian Synchrotron Light Laboratory (LNLS). The technique proved viable because it was able to detect five important metallic elements to environmental studies: Cr, Fe, Ni, Cu and Zn. This technique presented substantial efficiency in determining the elementary concentration of air pollutants, in addition to low cost. It can be concluded that the metals analysis technique in air samples using an impinger as sample collection instrument associated with a complexing agent (APDC) was viable because it is a low-cost technique, moreover, it was possible the detection of five important metal elements in environmental studies associated with industrial emissions and urban traffic. (author)

  19. Determination of metals in air samples using X-Ray fluorescence associated the APDC preconcentration technique

    Nardes, Raysa C.; Santos, Ramon S.; Sanches, Francis A.C.R.A.; Gama Filho, Hamilton S.; Oliveira, Davi F.; Anjos, Marcelino J.

    2015-01-01

    Air pollution has become one of the leading quality degradation factors of life for people in large urban centers. Studies indicate that the suspended particulate matter in the atmosphere is directly associated with risks to public health, in addition, it can cause damage to fauna, flora and public / cultural patrimonies. The inhalable particulate materials can cause the emergence and / or worsening of chronic diseases related to respiratory system and other diseases, such as reduced physical strength. In this study, we propose a new method to measure the concentration of total suspended particulate matter (TSP) in the air using an impinger as an air cleaning apparatus, preconcentration with APDC and Total Reflection X-ray Fluorescence technique (TXRF) to analyze the heavy metals present in the air. The samples were collected from five random points in the city of Rio de Janeiro/Brazil. Analyses of TXRF were performed at the Brazilian Synchrotron Light Laboratory (LNLS). The technique proved viable because it was able to detect five important metallic elements to environmental studies: Cr, Fe, Ni, Cu and Zn. This technique presented substantial efficiency in determining the elementary concentration of air pollutants, in addition to low cost. It can be concluded that the metals analysis technique in air samples using an impinger as sample collection instrument associated with a complexing agent (APDC) was viable because it is a low-cost technique, moreover, it was possible the detection of five important metal elements in environmental studies associated with industrial emissions and urban traffic. (author)

  20. The fundamental parameter method applied to X-ray fluorescence analysis with synchrotron radiation

    Pantenburg, F. J.; Beier, T.; Hennrich, F.; Mommsen, H.

    1992-05-01

    Quantitative X-ray fluorescence analysis applying the fundamental parameter method is usually restricted to monochromatic excitation sources. It is shown here, that such analyses can be performed as well with a white synchrotron radiation spectrum. To determine absolute elemental concentration values it is necessary to know the spectral distribution of this spectrum. A newly designed and tested experimental setup, which uses the synchrotron radiation emitted from electrons in a bending magnet of ELSA (electron stretcher accelerator of the university of Bonn) is presented. The determination of the exciting spectrum, described by the given electron beam parameters, is limited due to uncertainties in the vertical electron beam size and divergence. We describe a method which allows us to determine the relative and absolute spectral distributions needed for accurate analysis. First test measurements of different alloys and standards of known composition demonstrate that it is possible to determine exact concentration values in bulk and trace element analysis.

  1. Determination of sparfloxacin with CdSe/CdS quantum dots as fluorescent probes

    Hou, Ming, E-mail: gxglzws@foxmail.com; Yan, Xiaoya; Xiong, Ling

    2015-01-15

    Water-soluble CdSe/CdS quantum dots (QDs) modified with thioglycolic acid (TGA) were synthesized. A novel method for determination of sparfloxacin (SPFX) has been developed based on quenching of the fluorescence of QDs at 556 nm wavelength. The optimum fluorescence intensity was found in 0.067 mol L{sup −1} KH{sub 2}PO{sub 4}–Na{sub 2}HPO{sub 4} buffer solution at pH 6.47 of 3.0×10{sup −5} mol L{sup −1} QDs. When the concentration of quantum dots is 3.0×10{sup −5} mol L{sup −1} the fluorescence quenching intensity of QDs is linearly proportional to the concentration of SPFX from 0.5 μg mL{sup −1} to 30 μg mL{sup −1}, with correlation coefficient R=0.9983. The detection limit for SPFX was 0.1391 μg mL{sup −1}. The method was used for determination of SPFX in tablets, and the results agreed with the claimed value. Trace amounts of SPFX in milk were also determined with the recovery of 95.3–106.8%. - Highlights: • Water-soluble CdSe/CdS quantum dots modified with thioglycolic acid were synthesized. • Determination of sparfloxacin was based on quenching of the fluorescence of QDs. • The detection limit for sparfloxacin was 0.1391 μg mL{sup −1}. • The method has been used successfully to determine SPFX in tablets and milk.

  2. Protein determination in soya bean by fast neutron activation analysis

    Szegedi, S.; Mosbah, D.S.; Varadi, M.; Szaloki, I.

    1988-01-01

    For a non-destructive determination of the protein content in soya bean samples, 14-MeV neutron activation analysis was applied. To check the method, the results obtained by X-ray fluorescence analysis and the Kjeldahl procedure were compared. For pressed pellet samples of about 1 g with 15 min irradiation and 10 min measuring times the accuracy of the protein determination was found to be 15%. (author) 7 refs.; 4 figs.; 3 tabs

  3. Cu,Cr and As determination in preserved woods (Eucalyptus ssp.) by X-ray fluorescence spectrometries

    Pereira Junior, Sergio Matias

    2014-01-01

    Brazil produces around 2.2 millions of cubic meters of treated wood to meet the annual demand of railway, electric, rural and construction sectors. The most used wood species are eucalyptus (Eucalyptus ssp.) and pine (Pinus ssp.).The treated woods used for poles, sleepers, fence posts and plywoods should be according to Brazilian norms requirements. The most usual wood preservative products used in Brazil are CCA (chromated copper arsenate) and CCB (copper chromium and boron salt). The analytical methods, such as flame atomic absorption spectrometry (FAAS), plasma inductively coupled optical emission spectrometry (ICPOES) and X-ray fluorescence spectrometry (XRFS) have been used for the analytical control of those treatment processes. In this work, the eucalyptus trees (Eucalyptus ssp) samples was obtained from Minas Gerais State, Brazil, cut plantation areas. Under pressure, eucalyptus wood samples were submitted to different concentration of CCA solution reaching 3.9, 6.7, 9.1, 12.4 and 14.0 kg of CCA by m-³ sapwood retentions. Samples in cylinders and sawdust forms were obtained from treated wood samples. Copper, chromium and arsenic determination was performed using the energy dispersive X-ray fluorescence spectrometry (EDXRFS), portable X-ray fluorescence spectrometry (PXRFS), flame atomic absorption spectrometry (FAAS) and instrumental neutron activation analysis. In this work, the method of analysis, sensitivity, precision and accuracy performances of the related techniques were outlined. (author)

  4. Bias in the absorption coefficient determination of a fluorescent dye, standard reference material 1932 fluorescein solution

    DeRose, Paul C.; Kramer, Gary W.

    2005-01-01

    The absorption coefficient of standard reference material[registered] (SRM[registered]) 1932, fluorescein in a borate buffer solution (pH=9.5) has been determined at λ=488.0, 490.0, 490.5 and 491.0 nm using the US national reference UV/visible spectrophotometer. The purity of the fluorescein was determined to be 97.6% as part of the certification of SRM 1932. The solution measured was prepared gravimetrically by diluting SRM 1932 with additional borate buffer. The value of the absorption coefficient was corrected for bias due to fluorescence that reaches the detector and for dye purity. Bias due to fluorescence was found to be on the order of -1% for both monochromatic and polychromatic (e.g., diode-array based) spectrophotometers

  5. Single excitation-emission fluorescence spectrum (EEF) for determination of cetane improver in diesel fuel.

    Insausti, Matías; Fernández Band, Beatriz S

    2015-04-05

    A highly sensitive spectrofluorimetric method has been developed for the determination of 2-ethylhexyl nitrate in diesel fuel. Usually, this compound is used as an additive in order to improve cetane number. The analytical method consists in building the chemometric model as a first step. Then, it is possible to quantify the analyte with only recording a single excitation-emission fluorescence spectrum (EEF), whose data are introduced in the chemometric model above mentioned. Another important characteristic of this method is that the fuel sample was used without any pre-treatment for EEF. This work provides an interest improvement to fluorescence techniques using the rapid and easily applicable EEF approach to analyze such complex matrices. Exploding EEF was the key to a successful determination, obtaining a detection limit of 0.00434% (v/v) and a limit of quantification of 0.01446% (v/v). Copyright © 2015 Elsevier B.V. All rights reserved.

  6. [Sensitive Determination of Chondroitin Sulfate by Fluorescence Recovery of an Anionic Aluminum Phthalocyanine-Cationic Surfactant Ion-Association Complex Used as a Fluorescent Probe Emitting at Red Region].

    Chen, Lin; Huang, Ping; Yang, Hui-qing; Deng, Ya-bin; Guo, Meng-lin; Li, Dong-hui

    2015-08-01

    Determination of chondroitin sulfate in the biomedical field has an important value. The conventional methods for the assay of chondroitin sulfate are still unsatisfactory in sensitivity, selectivity or simplicity. This work aimed at developing a novel method for sensitive and selective determination of chondroitin sulfate by fluorimetry. We found that some kinds of cationic surfactants have the ability to quench the fluorescence of tetrasulfonated aluminum phthalocyanine (AlS4Pc), a strongly fluorescent compound which emits at red region, with high efficiency. But, the fluorescence of the above-mentioned fluorescence quenching system recovered significantly when chondroitin sulfate (CS) exits. Tetradecyl dimethyl benzyl ammonium chloride(TDBAC) which was screened from all of the candidates of cationic surfactants was chosen as the quencher because it shows the most efficient quenching effect. It was found that the fluorescence of AlS4Pc was extremely quenched by TDBAC because of the formation of association complex between AlS4Pc and TDBAC. Fluorescence of the association complex recovered dramatically after the addition of chondroitin sulfate (CS) due to the ability of chondroitin sulfate to shift the association equilibrium of the association, leading to the release of AlS4Pc, thus resulting in an increase in the fluorescence of the reaction system. Based on this phenomenon, a novel method with simplicity, accuracy and sensitivity was developed for quantitative determination of CS. Factors including the reaction time, influencing factors and the effect of coexisting substances were investigated and discussed. Under optimum conditions the linear range of the calibration curve was 0.20~10.0 μg · mL(-1). The detection limit for CS was 0.070 μg · mL(-1). The method has been applied to the analysis of practical samples with satisfied results. This work expands the applications of AlS4Pc in biomedical area.

  7. Preparation and Fluorescent Analysis of Plant Metaphase Chromosomes.

    Schwarzacher, Trude

    2016-01-01

    Good preparations are essential for informative analysis of both somatic and meiotic chromosomes, cytogenetics, and cell divisions. Fluorescent chromosome staining allows even small chromosomes to be visualized and counted, showing their morphology. Aneuploidies and polyploidies can be established for species, populations, or individuals while changes occurring in breeding lines during hybridization or tissue culture and transformation protocols can be assessed. The process of division can be followed during mitosis and meiosis including pairing and chiasma distribution, as well as DNA organization and structure during the evolution of chromosomes can be studied. This chapter presents protocols for pretreatment and fixation of material, including tips of how to grow plants to get good and healthy meristem with many divisions. The chromosome preparation technique is described using proteolytic enzymes, but acids can be used instead. Chromosome slide preparations are suitable for fluorochrome staining for fast screening (described in the chapter) or fluorescent in situ hybridization (see Schwarzacher and Heslop-Harrison, In situ hybridization. BIOS Scientific Publishers, Oxford, 2000).

  8. The use of fluorescent indoline dyes for side population analysis.

    Kohara, Hiroshi; Watanabe, Kohei; Shintou, Taichi; Nomoto, Tsuyoshi; Okano, Mie; Shirai, Tomoaki; Miyazaki, Takeshi; Tabata, Yasuhiko

    2013-01-01

    Dye efflux assay evaluated by flow cytometry is useful for stem cell studies. The side population (SP) cells, characterized by the capacity to efflux Hoechst 33342 dye, have been shown to be enriched for hematopoietic stem cells (HSCs) in bone marrow. In addition, SP cells are isolated from various tissues and cell lines, and are also potential candidates for cancer stem cells. However, ultra violet (UV) light, which is not common for every flow cytometer, is required to excite Hoechst 33342. Here we showed that a fluorescent indoline dye ZMB793 can be excited by 488-nm laser, equipped in almost all the modern flow cytometers, and ZMB793-excluding cells showed SP phenotype. HSCs were exclusively enriched in the ZMB793-excluding cells, while ZMB793 was localized in cytosol of bone marrow lineage cells. The efflux of ZMB793 dye was mediated by ATP binding cassette (ABC) transporter Abcg2. Moreover, staining properties were affected by the side-chain structure of the dyes. These data indicate that the fluorescent dye ZMB793 could be used for the SP cell analysis. Copyright © 2012 Elsevier Ltd. All rights reserved.

  9. Determination of adenine based on the fluorescence recovery of the L-Tryptophan-Cu(2+) complex.

    Duan, Ruilin; Li, Chunyan; Liu, Shaopu; Liu, Zhongfang; Li, Yuanfang; Yuan, Yusheng; Hu, Xiaoli

    2016-01-05

    A simple and sensitive method for determination of adenine was developed based on fluorescence quenching and recovery of L-Tryptophan (L-Trp). The fluorescence of L-Trp could efficiently quenched by copper ion compared with other common metal ions. Upon addition of adenine (Ade) in L-Trp-Cu(II) system, the fluorescence was reoccurred. Under the optimum conditions, the recovery fluorescence intensity was linearly correlated with the concentration of adenine in the range from 0.34 to 25.0μmolL(-1), with a correlation coefficient (R(2)) of 0.9994. The detection limit (3σ/k) was 0.046μmolL(-1), indicating that this method could applied to detect trace adenine. In this study, amino acids including L-Trp, D-Trp, L-Tyr, D-Tyr, L-Phe, D-Phe were investigated and only L-Trp could well chelated copper ion. Additionally, the mechanism of quench and recovery also were discussed and the method was successfully applied to detect the adenine in DNA with satisfactory results. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Fluorescent Biosensor for Phosphate Determination Based on Immobilized Polyfluorene-Liposomal Nanoparticles Coupled with Alkaline Phosphatase.

    Kahveci, Zehra; Martínez-Tomé, Maria José; Mallavia, Ricardo; Mateo, C Reyes

    2017-01-11

    This work describes the development of a novel fluorescent biosensor based on the inhibition of alkaline phosphatase (ALP). The biosensor is composed of the enzyme ALP and the conjugated cationic polyfluorene HTMA-PFP. The working principle of the biosensor is based on the fluorescence quenching of this polyelectrolyte by p-nitrophenol (PNP), a product of the hydrolysis reaction of p-nitrophenyl phosphate (PNPP) catalyzed by ALP. Because HTMA-PFP forms unstable aggregates in buffer, with low fluorescence efficiency, previous stabilization of the polyelectrolyte was required before the development of the biosensor. HTMA-PFP was stabilized through its interaction with lipid vesicles to obtain stable blue-emitting nanoparticles (NPs). Fluorescent NPs were characterized, and the ability to be quenched by PNP was evaluated. These nanoparticles were coupled to ALP and entrapped in a sol-gel matrix to produce a biosensor that can serve as a screening platform to identify ALP inhibitors. The components of the biosensor were examined before and after sol-gel entrapment, and the biosensor was optimized to allow the determination of phosphate ion in aqueous medium.

  11. Determination of Dynamics of Plant Plasma Membrane Proteins with Fluorescence Recovery and Raster Image Correlation Spectroscopy.

    Laňková, Martina; Humpolíčková, Jana; Vosolsobě, Stanislav; Cit, Zdeněk; Lacek, Jozef; Čovan, Martin; Čovanová, Milada; Hof, Martin; Petrášek, Jan

    2016-04-01

    A number of fluorescence microscopy techniques are described to study dynamics of fluorescently labeled proteins, lipids, nucleic acids, and whole organelles. However, for studies of plant plasma membrane (PM) proteins, the number of these techniques is still limited because of the high complexity of processes that determine the dynamics of PM proteins and the existence of cell wall. Here, we report on the usage of raster image correlation spectroscopy (RICS) for studies of integral PM proteins in suspension-cultured tobacco cells and show its potential in comparison with the more widely used fluorescence recovery after photobleaching method. For RICS, a set of microscopy images is obtained by single-photon confocal laser scanning microscopy (CLSM). Fluorescence fluctuations are subsequently correlated between individual pixels and the information on protein mobility are extracted using a model that considers processes generating the fluctuations such as diffusion and chemical binding reactions. As we show here using an example of two integral PM transporters of the plant hormone auxin, RICS uncovered their distinct short-distance lateral mobility within the PM that is dependent on cytoskeleton and sterol composition of the PM. RICS, which is routinely accessible on modern CLSM instruments, thus represents a valuable approach for studies of dynamics of PM proteins in plants.

  12. Elimination of matrix effect in quantitative analysis of elements using x-ray fluorescence

    Sampaio, R.V.

    1973-07-01

    The emission-transmission method of Leroux and Mahmud, an experimental technique for compensating matrix effects in photon excited X-ray fluorescence analysis, was used to determine the concentration of lead and antimony in pellets of galalith. The effect of interfering elements was studied by adding various concentrations of mercury and tin to the respective pellets. To illustrate possible environmental applications, a number of pellets was prepared from leaves of almond trees located in different regions of Rio de Janeiro. Lead concentrations were determined for the dried leaf material and showed values ranging from 50 to 145 parts per million [pt

  13. Analysis of fresco paintings by X-ray fluorescence method

    Cechak, T.; Gerndt, J.; Musilek, L.; Kopecka, I.

    2000-01-01

    In this work we present the application of X-ray fluorescence analysis (XRFA) to examine fresco paintings from the Karlstejn castle. The X-ray fluorescence apparatus built and operated in the Laboratory of Quantitative Methods in Research of Ancient Monuments was used for the purpose of fresco paintings measurements. The X-ray sources (radionuclides) generate the characteristic X-ray photons from the sample. The Si(Li) detector measures numbers and energies of photons emitted from the specimen. The energy and number of photons detected can be converted into kind and amount of measured atoms. These results give data for qualitative and quantitative analysis of samples. XRFA is relatively simple and non-destructive method. Capability of in-situ measurement is one of big advantages of this method. The radionuclide sources of exciting radiation (e.g. 55 Fe enables the excitation of elements with Z up to 23, 238 Pu is used in interval of Z from 20 to 39 etc.) were used. An Si(Li) semiconductor detector with a 5 l Dewar vessel and portable spectroscopy system enable the in situ measurement. Narrow collimation of the exciting beam makes it possible to select the measured area of fresco painting. The valuable fresco paintings from the Karlstejn castle were investigated in this way. The measurements were carried out in collaboration with the Analytical Laboratory of the State Institute for the Preservation of Historic Monuments. A suitable analysis of paintings makes it possible to detect the kind of colours and evaluate changes in the surface colour of paintings and suggest useful and timely procedures for their conservation and restoration. (author)

  14. Optimization of the Analytical Method Using HPLC with Fluorescence Detection to Determine Selected Polycyclic Aromatic Compounds in Clean Water Samples

    Garcia Alonso, S.; Perez Pastor, R. M.

    2013-01-01

    A study on the comparison and evaluation of 3 miniaturized extraction methods for the determination of selected PACs in clear waters is presented. Three types of liquid-liquid extraction were used for chromatographic analysis by HPLC with fluorescence detection. The main objective was the optimization and development of simple, rapid and low cost methods, minimizing the use of extracting solvent volume. The work also includes a study on the scope of the methods developed at low and high levels of concentration and intermediate precision. (Author)

  15. Determination of coal ash content by the combined x-ray fluorescence and scattering spectrum

    Mikhailov, I. F.; Baturin, A. A.; Mikhailov, A. I.; Borisova, S. S.; Fomina, L. P.

    2018-02-01

    An alternative method is proposed for the determination of the inorganic constituent mass fraction (ash) in solid fuel by the ratio of Compton and Rayleigh X-ray scattering peaks IC/IR subject to the iron fluorescence intensity. An original X-ray optical scheme with a Ti/Mo (or Sc/Cu) double-layer secondary radiator allows registration of the combined fluorescence-and-scattering spectrum at the specified scattering angle. An algorithm for linear calibration of the Compton-to-Rayleigh IC/IR ratio is proposed which uses standard samples with two certified characteristics: mass fractions of ash (Ad) and iron oxide (WFe2O3). Ash mass fractions have been determined for coals of different deposits in the wide range of Ad from 9.4% to 52.7% mass and WFe2O3 from 0.3% to 4.95% mass. Due to the high penetrability of the probing radiation with energy E > 17 keV, the sample preparation procedure is rather simplified in comparison with the traditional method of Ad determination by the sum of fluorescence intensities of all constituent elements.

  16. Determination of chlorine in coal by X-ray fluorescence spectrometry method

    Marek, S.; Bojarska, K. [Central Mining Institute, Katowice (Poland). Dept. of Environmental Monitoring

    1997-12-31

    Determination of chlorine contents in coal is essential for both environmental protection and its technological use. The existing method of chlorine determination in coal are titration methods which have considerable errors particularly in the low concentration range. The elaborated method with the use of X-ray fluorescence spectrometry in a comparison to the other methods is much faster and has better precision and accuracy. The principle of the method lies in the measurement of X-ray fluorescence radiation intensity which is emitted by chlorine in a sample and its comparison with standards. The calibration of the elaborated XRF method is based on natural coals having various concentrations of chlorine within the whole range of its occurrence in Polish coals. Concentrations for the calibration purpose were obtained by the determination of chlorine contents in selected coals by atomic absorption spectrometry method. The procedure of sample preparation for direct X-ray measurements, instrumental measuring conditions and the way of calibration curve preparation are described in the paper. All X-ray measurements were done with a Phillips sequential X-ray fluorescence spectrometer. A double anode Cr-Au X-ray tube with maximum power 3000 MW was used as the excitation source. 5 figs., 4 tabs.

  17. Analysis of solar blocker through portable X-ray fluorescence

    Ferreira, Diego de Dio; Melquiades, Fabio Luiz; Appoloni, Carlos Roberto; Lopes, Fabio; Lonni, Audrey Stinghen G.; Oliveira, Frederico Minardi de; Duarte, Jose C.

    2009-01-01

    This paper estimates the concentration of TiO 2 by Energy Dispersion X-ray fluorescence (EDXRF) viewing t obtain the FPS due to the physical barrier in the composition of solar blockers, and identifies possible present metals in the samples. A portable EDXRF equipment was used and 27 commercial of different brands and solar protection factors were analysed. Also, three formulations (A, B and C) were prepared and measured estimated in FPS-30 using 5% or TiO 2 . The quantification was performed through calibration curves with 1% to 30% standards of TiO 2 . As result, it was possible to determine the contribution to physical protection in the FPS, associated to the Ti concentration present in some solar blocker samples available in the market. Also, it was possible to detect the presence of various metals in solar protectors, such as Fe, Zn, Br and Sr, and identify chemical elements which were not mentioned and their formulation as well

  18. Application of direct peak analysis to energy dispersive x-ray fluorescence spectra

    Nielson, K.K.

    1977-07-01

    A modified Covell method for direct peak analysis has been applied to energy dispersive x-ray fluorescence spectra. The method is background independent and is well-suited to computerized data reduction. It provides acceptable precision, minimizes errors from instrumental gain shift, and permits peak overlap correction. Peak overlap errors exhibit both positive and negative nodes as a function of peak separation distance, and are corrected using concentration ratios determined from thin, single-element standards. Peak precisions and overlaps are evaluated as a function of window width to aid in width selection. Least-square polynomial smoothing prior to peak analysis significantly improves peak area precisions without significantly affecting their accuracies

  19. The x-rays fluorescence applied to the analysis of alloys

    Gutierrez, D.A.

    1997-01-01

    This work is based on the utilization of the Fluorescence of X Rays. This technique of non destructive trial, has the purpose to establish a routine method, for the control of the conformation of industrial samples used. It makes an analysis with a combination of the algorithms of Rasberry-Heinrich and Claisse-Thinh. Besides, the numerical implementation of non usual techniques in this type of analysis. Such as the Linear Programming applied to the solution of super determined systems, of equations and the utilization of methods of relaxation to facilitate the convergence to the solutions. (author) [es

  20. Occurrence of aflatoxins in peanuts and peanut products determined by liquid chromatography with fluorescence detection

    Stojanovska-Dimzoska Biljana

    2013-01-01

    Full Text Available Liquid chromatography with fluorescence detection using immunoaffinity column clean-up was a method described for determination of aflatoxins (AFB1, AFB2, AFG1 and AFG2 in peanuts and peanut based products. The validation of the procedure was performed. Good coefficient of correlation was found for all aflatoxins in the range of 0.9993-0.9999. Limit of detection (LOD and limit of quantification (LOQ ranged from 0.003-0.005 mg/kg and 0.009-0.023 mg/kg, respectively, which was acceptable. The mean recovery for total aflatoxins was 88.21%. The method also showed acceptable precision values in the range of 0.171-2.626% at proposed concentration levels for all four aflatoxins. RSDR values (within laboratory reproducibility calculated from the results showed good correlation between two analysts for all aflatoxins and they ranged from 4.93-11.87%. The developed method was applied for the determination of aflatoxins in 27 samples of peanuts and peanut based products. The results showed that 21 peanut samples (77.7% were below LOD of the method. Three samples had positive results over the MRL. There was one extreme value recorded for the total aflatoxins in peanut (289.2 mg/kg and two peanut based products, peanut snack and peanut, with total content of aflatoxins being 16.3 mg/kg and 8.0 mg/kg, respectively. The obtained results demonstrated that the procedure was suitable for the de­termination of aflatoxins in peanuts and peanut based products and it could be implemented for the routine analysis.

  1. Determination of the mass attenuation coefficients for X-ray fluorescence measurements correction by the Rayleigh to Compton scattering ratio

    Conti, C. C.; Anjos, M. J.; Salgado, C. M.

    2014-09-01

    X-ray fluorescence technique plays an important role in nondestructive analysis nowadays. The development of equipment, including portable ones, enables a wide assortment of possibilities for analysis of stable elements, even in trace concentrations. Nevertheless, despite of the advantages, one important drawback is radiation self-attenuation in the sample being measured, which needs to be considered in the calculation for the proper determination of elemental concentration. The mass attenuation coefficient can be determined by transmission measurement, but, in this case, the sample must be in slab shape geometry and demands two different setups and measurements. The Rayleigh to Compton scattering ratio, determined from the X-ray fluorescence spectrum, provides a link to the mass attenuation coefficient by means of a polynomial type equation. This work presents a way to construct a Rayleigh to Compton scattering ratio versus mass attenuation coefficient curve by using the MCNP5 Monte Carlo computer code. The comparison between the calculated and literature values of the mass attenuation coefficient for some known samples showed to be within 15%. This calculation procedure is available on-line at www.macx.net.br.

  2. Chemical analysis of copper and gold ores from Papua New Guinea (PNG) by means of X-ray fluorescence analysis

    Sugiyama, Kazumasa; Waseda, Yoshio; Pangum, L.S.; Witney, J.Y.

    1995-01-01

    X-ray fluorescence analysis (XRF) has been made for determining the contents of copper and gold in ores from PNG mines. An internal standard method of Cu Kα/Er Lβ 1 was used for the analysis of the common copper porphyry samples. The results clearly indicate that this technique is quite effective for analyzing any copper ores with complicated matrix elements. On the other hand, an addition method of the diluted Au solution was applied to gold ores. The results of the present XRF analysis were found to reasonably agree with those obtained by the inductively coupled plasma (ICP) technique. (author)

  3. Gaseous detectors for energy dispersive X-ray fluorescence analysis

    Veloso, J. F. C. A.; Silva, A. L. M.

    2018-01-01

    The energy resolution capability of gaseous detectors is being used in the last years to perform studies on the detection of characteristic X-ray lines emitted by elements when excited by external radiation sources. One of the most successful techniques is the Energy Dispersive X-ray Fluorescence (EDXRF) analysis. Recent developments in the new generation of micropatterned gaseous detectors (MPGDs), triggered the possibility not only of recording the photon energy, but also of providing position information, extending their application to EDXRF imaging. The relevant features and strategies to be applied in gaseous detectors in order to better fit the requirements for EDXRF imaging will be reviewed and discussed, and some application examples will be presented.

  4. Direct analysis of biological samples by total reflection X-ray fluorescence

    Lue M, Marco P.; Hernandez-Caraballo, Edwin A.

    2004-01-01

    The technique of total reflection X-ray fluorescence (TXRF) is well suited for the direct analysis of biological samples due to the low matrix interferences and simultaneous multi-element nature. Nevertheless, biological organic samples are frequently analysed after digestion procedures. The direct determination of analytes requires shorter analysis time, low reactive consumption and simplifies the whole analysis process. On the other hand, the biological/clinical samples are often available in minimal amounts and routine studies require the analysis of large number of samples. To overcome the difficulties associated with the analysis of organic samples, particularly of solid ones, different procedures of sample preparation and calibration to approach the direct analysis have been evaluated: (1) slurry sampling, (2) Compton peak standardization, (3) in situ microwave digestion, (4) in situ chemical modification and (5) direct analysis with internal standardization. Examples of analytical methods developed by our research group are discussed. Some of them have not been previously published, illustrating alternative strategies for coping with various problems that may be encountered in the direct analysis by total reflection X-ray fluorescence spectrometry

  5. Beer analysis by synchrotron radiation total reflection X-ray fluorescence (SR-TXRF)

    Moreira, Silvana; Vives, Ana Elisa S. de; Nascimento Filho, Virgilio F.; Zucchi, Orgheda L.D.A.

    2005-01-01

    In this work the concentrations of P, S, Cl, K, Ca, Mn, Fe, Zn and Br in twenty-nine brands of national and international beers were determined by Synchrotron Radiation Total Reflection X-Ray Fluorescence analysis (SR-TXRF). The results were compared with the limits established by the Brazilian Legislation and the nutritive values established by National Agricultural Library (NAL). The measurements were performed at the X-ray Fluorescence Beamline at Synchrotron Light Source Laboratory, in Campinas, Sao Paulo, Brazil, using a polychromatic beam for excitation. A small volume of 5 μL of sample beers containing just an internal standard, used to correct geometry effects, were analyzed without any pre-treatment. The measuring time was 100 s and the detection limits obtained varied from 1μg.L -1 for Mn and Fe to 15μg.L -1 for P. (author)

  6. Quantitative analysis and metallic coating thickness measurements by X-ray fluorescence

    Negrea, Denis; Ducu, Catalin; Malinovschi, Viorel; Moga, Sorin; Boicea, Niculae

    2009-01-01

    Full text: This paperwork covers the use of X-ray fluorescence (XRF) for determining the concentration and the coating thickness on metallic samples. The analysis method presented here may also be applicable to other coatings, providing that the elemental nature of the coating and substrate are compatible with the technical aspects of XRF, such as the absorption coefficient of the system, primary radiation, fluorescent radiation and type of detection. For the coating thickness measurement it was used the substrate-line attenuation method and a computing algorithm was developed. Its advantage relies in the fact that no special calibration with standard samples having different layer thickness is needed. The samples used for evaluation were metallic pieces of iron with zinc-nickel coatings of different thickness obtained by electrochemical deposition. (authors)

  7. Quantitative analysis and metallic coating thickness measurements by X-ray fluorescence

    Negrea, Denis; Ducu, Catalin; Malinovschi, Viorel; Moga, Sorin; Boicea, Niculae

    2009-01-01

    This work deals with the use of X-ray fluorescence (XRF) for determining the concentration and the coating thickness on metallic samples. The analysis method presented here may also be applicable to other coatings, providing that the elemental nature of the coating and substrate are compatible with the technical aspects of XRF, such as the absorption coefficient of the system, primary radiation, fluorescent radiation and type of detection. For the coating thickness measurement it was used the substrate-line attenuation method and an algorithm was developed. Its advantage relies in the fact that no special calibration with standard samples having different layer thickness is needed. The samples used for evaluation were metallic pieces of iron with zinc-nickel coatings of different thickness obtained by electrochemical deposition. (authors)

  8. Data analysis of x-ray fluorescence holography by subtracting normal component from inverse hologram

    Happo, Naohisa; Hayashi, Kouichi; Hosokawa, Shinya

    2010-01-01

    X-ray fluorescence holography (XFH) is a powerful technique for determining three-dimensional local atomic arrangements around a specific fluorescing element. However, the raw experimental hologram is predominantly a mixed hologram, i.e., a mixture of hologram generated in both normal and inverse modes, which produces unreliable atomic images. In this paper, we propose a practical subtraction method of the normal component from the inverse XFH data by a Fourier transform for the calculated hologram of a model ZnTe cluster. Many spots originating from the normal components could be properly removed using a mask function, and clear atomic images were reconstructed at adequate positions of the model cluster. This method was successfully applied to the analysis of experimental ZnTe single crystal XFH data. (author)

  9. Beer analysis by synchrotron radiation total reflection X-ray fluorescence (SR-TXRF)

    Moreira, Silvana [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia Civil, Arquitetura e Urbanismo. Dept. de Recursos Hidricos]. E-mail: silvana@fec.unicamp.br; Vives, Ana Elisa S. de [Universidade Metodista de Piracicaba (UNIMEP), Santa Barbara D' Oeste, SP (Brazil). Faculdade de Engenharia, Arquitetura e Urbanismo]. E-mail: aesvives@unimep.br; Nascimento Filho, Virgilio F. [Centro de Energia Nuclear na Agricultura (CENA), Piracicaba, SP (Brazil). Lab. de Instrumentacao Nuclear]. E-mail: virgilio@cena.usp.br; Zucchi, Orgheda L.D.A. [Sao Paulo Univ., Ribeirao Preto, SP (Brazil). Faculdade de Ciencias Farmaceuticas de Ribeirao Preto]. E-mail: olzucchi@fcfrp.usp.br

    2005-07-01

    In this work the concentrations of P, S, Cl, K, Ca, Mn, Fe, Zn and Br in twenty-nine brands of national and international beers were determined by Synchrotron Radiation Total Reflection X-Ray Fluorescence analysis (SR-TXRF). The results were compared with the limits established by the Brazilian Legislation and the nutritive values established by National Agricultural Library (NAL). The measurements were performed at the X-ray Fluorescence Beamline at Synchrotron Light Source Laboratory, in Campinas, Sao Paulo, Brazil, using a polychromatic beam for excitation. A small volume of 5 {mu}L of sample beers containing just an internal standard, used to correct geometry effects, were analyzed without any pre-treatment. The measuring time was 100 s and the detection limits obtained varied from 1{mu}g.L{sup -1} for Mn and Fe to 15{mu}g.L{sup -1} for P. (author)

  10. Electroadsorption-assisted direct determination of trace arsenic without interference using transmission X-ray fluorescence spectroscopy.

    Jiang, Tian-Jia; Guo, Zheng; Liu, Jin-Huai; Huang, Xing-Jiu

    2015-08-18

    An analytical technique based on electroadsorption and transmission X-ray fluorescence (XRF) for the quantitative determination of arsenic in aqueous solution with ppb-level limits of detection (LOD) is proposed. The approach uses electroadsorption to enhance the sensitivity and LOD of the arsenic XRF response. Amine-functionalized carbonaceous microspheres (NH2-CMSs) are found to be the ideal materials for both the quantitative adsorption of arsenic and XRF analysis due to the basic amine sites on the surface and their noninterference in the XRF spectrum. In electroadsorptive X-ray fluorescence (EA-XRF), arsenic is preconcentrated by a conventional three-electrode system with a positive electricity field around the adsorbents. Then, the quantification of arsenic on the adsorbents is achieved using XRF. The electroadsorption preconcentration can realize the fast transfer of arsenic from the solution to the adsorbents and improve the LOD of conventional XRF compared with directly determining arsenic solution by XRF alone. The sensitivity of 0.09 cnt ppb(-1) is obtained without the interferences from coexisted metal ions in the determination of arsenic, and the LOD is found to be 7 ppb, which is lower than the arsenic guideline value of 10 ppb given by the World Health Organization (WHO). These results demonstrated that XRF coupled with electroadsorption was able to determine trace arsenic in real water sample.

  11. Critical tonicity determination of sperm using fluorescent staining and flow cytometry

    Noiles, E.E.; Ruffing, N.A.; Kleinhans, F.W.; Mark, L.A.; Watson, P.F.; Critser, J.K. (Methodist Hospital, Indianapolis, IN (USA)); Horstman, L. (Purdue Univ., Lafayette, IN (USA). School of Veterinary Medicine); Mazur, P. (Oak Ridge National Lab., TN (USA))

    1990-01-01

    The use of cryopreserved, rather than fresh, mammalian semen for artificial insemination confers several important medical and/or economic advantages. However, current methods for cryopreservation of both human and bovine spermatozoa result in approximately only a 50% survival rate with thawing, obviously reducing the fertilizing capacity of the semen. A primary consideration during the cooling process is to avoid intracellular ice crystal formation with its lethal consequences to the cell. Current techniques achieve this by controlling the cooling rate. Computation of the time necessary for this dehydration, and hence, the cooling rate, is dependent upon knowledge of the water permeability coefficient (L{sub {rho}}) and its activation energy. The fluorophore, 6-carboxyfluoroscein diacetate (CFDA), which is nonfluorescent, readily crosses the intact plasma membrane. Intracellular esterases hydrolyze CFDA to 6-carboxyfluoroscein, a fluorescent, membrane-impermeable fluorophore. Consequently, spermatozoa with intact plasma membranes fluoresce bright green (Garner et. al., 1986), but those with disrupted membranes do not. Therefore, the purpose of this study was to use loss of CFDA fluorescence to determine the osmolality at which 50% of the spermatozoa will swell and lyse (critical tonicity, CT). These data will then be used to determine the L{sub {rho}} and its activation energy for sperm, thus increasing the knowledge available in cellular cryopreservation. 15 refs., 3 figs.

  12. Determination of human albumin in serum and urine samples by constant-energy synchronous fluorescence method.

    Madrakian, Tayyebeh; Bagheri, Habibollah; Afkhami, Abbas

    2015-08-01

    A sensitive spectrofluorimetric method using constant-energy synchronous fluorescence technique is proposed for the determination of human albumin without separation. In this method, no reagent was used for enhancement of the fluorescence signal of albumin in the solution. Effects of some parameters, such as energy difference between excitation and emission monochromators (ΔE), emission and excitation slit widths and scan rate of wavelength were studied and the optimum conditions were established. For this purpose factorial design and response surface method were employed for optimization of the effective parameters on the fluorescence signal. The results showed that the scan rate of the wavelength has no significant effect on the analytical signal. The calibration curve was linear in the range 0.1-220.0 µg mL(-1) of albumin with a detection limit of 7.0 × 10(-3)  µg mL(-1). The relative standard deviations (RSD) for six replicate measurements of albumin were calculated as 2.2%, 1.7% and 1.3% for 0.5, 10.0 and 100.0 µg mL(-1) albumin, respectively. Furthermore the proposed method has been employed for the determination of albumin in human serum and urine samples. Copyright © 2014 John Wiley & Sons, Ltd.

  13. The determination, by x-ray-fluorescence spectrometry, of gold in activated charcoal

    Austen, C.E.

    1977-01-01

    A rapid method is described for the determination of gold in activated charcoal by X-ray-fluorescence spectrometry. Compensation for matrix effects is achieved by means of platinum that is added for use as an internal standard. Calibration is achieved by use of a series of synthetic standards that are made by the spiking of barren charcoal with gold and platinum. The limit of determination is about 8 p.p.m. of gold, and the relative standard deviation is 1,2 per cent at a concentration level of 2300 p.p.m

  14. Continuous determination of gaseous ammonia in the ambient atmosphere using fluorescence derivatization

    Abbas, Rana; Tanner, Roger L.

    A method for continuous determination of ambient ammonia levels employing o-phthalaldehyde fluorescence derivatization is described. A simplified Venturi scrubber and gas-liquid separator have been employed for reproducible measurements of ⩾ 0.1 ppb ambient ammonia with less than 2 min time resolution. The scrubbing efficiency of the ammonia gas collection system was determined to be 29 ± 1 %. During 4 d in August 1979 ambient ammonia levels at the Brookhaven National Laboratory site averaged about 1.5 ± 1.1 ppb during afternoon daylight hours.

  15. Micellar Enhanced Three-Dimensional Excitation-Emission Matrix Fluorescence for Rapid Determination of Antihypertensives in Human Plasma with Aid of Second-Order Calibration Methods

    Hai-Yan Fu

    2015-01-01

    Full Text Available A highly sensitive three-dimensional excitation-emission fluorescence method was proposed to determine antihypertensives including valsartan and amlodipine besylate in human plasma with the aid of second-order calibration methods based on parallel factor analysis (PARAFAC and alternating trilinear decomposition (ATLD algorithms. Antihypertensives with weak fluorescent can be transformed into a strong fluorescent property by changing microenvironment in samples using micellar enhanced surfactant. Both the adopted algorithms with second-order advantage can improve the resolution and directly attain antihypertensives concentration even in the presence of potential strong intrinsic fluorescence from human plasma. The satisfactory results can be achieved for valsartan and amlodipine besylate in complicated human plasma. Furthermore, some statistical parameters and figures of merit were evaluated to investigate the performance of the proposed method, and the accuracy and precision of the proposed method were also validated by the elliptical joint confidence region (EJCR test and repeatability analysis of intraday and interday assay. The proposed method could not only light a new avenue to directly determine valsartan or amlodipine besylate in human plasma, but also hold great potential to be extended as a promising alternative for more practical applications in the determination of weak fluorescent drugs.

  16. Determination of copper in geological materials by X-ray fluorescence

    Roca, M.; Bayon, A.

    1981-01-01

    X-ray fluorescence has been applied to the determination of copper content of geological materials in the concentration range of 0.01 to % CuO. A molybdenum target tube Is used, samples being presented in finely-ground powder form. Various methods for the correction for background and Instrumental copper interferences have been considered. To correct for matrix effects different tube scattered primary radiations have been tested as references or internal standards. MoK(41 - (C) provides the most suitable results. The use of influence empirical coefficients for the effect of iron on copper and of mass absorption coefficients has also been considered. For samples with a high content of lead, several procedures to correct for I t s influence have been investigated. Comparison between data obtained by X-ray fluorescence and wet-chemical techniques indicated good agreement. (Author) 6 refs

  17. 3D Synchrotron μ-x-ray fluorescence analysis on human bones

    Zoeger, N.; Wobrauschek, P.; Streli, C.; Chinea-Cano, E.; Wegrzynek, D.; Roschger, P.; Simon, R.; Staub, S.; Falkenberg, G.

    2004-01-01

    A comparison between μ-x-ray fluorescence tomography and confocal μ-x-ray fluorescence analysis (μ-XRF) will be presented. These techniques were used to study the three dimensional (3D) elemental distribution in human bone. Since bone shows very strong inhomogeneities in structure as well as in distribution of the chemical elements, two dimensional (2D) analysis (element mapping) of the samples always led to difficulties in interpreting the results and assigning elemental distributions to microscopic structures. Tomography scans in fluorescence and absorption mode have been carried out simultaneously at the fluo-topo beamline at ANKA, Karlsruhe, to determine the distribution of the elements over the depth of the previously prepared sample from human patella. A monochromatized x-ray beam (17 keV) from a bending magnet station focused by a compound refractive lens to a beamsize of 10 x 5 μm was used to perform the measurements. The transmitted beam signal measured with the SD detector was utilized to apply a simplified absorption correction to XRF tomographic images. Based on the XRF sinograms the elemental distribution within the object cross-section was reconstructed by means of filtered backprojection. The same section of human bone has been analyzed by confocal μ-XRF at HASYLAB, Hamburg, Germany beamline L. With this experiment two polycapillary half lenses were used; one for focusing the previously monochromatized primary x-ray beam onto the sample and the second half lens in front of a Si(Li) detector to get a small inspected area. By overlapping the two foci of the lenses a very well defined volume of investigation could be defined. Scanning the sample up- and downstream it was possible to determine the elemental distribution in depth of the sample. An absorption correction has been applied to get a corrected fluorescence image of the sample. Both methods showed consistent results and allowed a precise localization of the elements of interest. (author)

  18. Liquid chromatographic determination with fluorescence detection of B6 vitamers and riboflavin in milk and pharmaceuticals

    Gatti, R.; Gioia, M.G.

    2005-01-01

    A simple, reliable and selective high performance liquid chromatographic method with fluorescence detection at different programmed wavelengths has been developed for the simultaneous analysis of B 6 vitamers (pyridoxal 5'-phosphate, 4-pyridoxic acid, pyridoxal, pyridoxine and pyridoxamine) and Vitamin B 2 in commercial vitaminized milk and in woman milk. The chromatographic separations were performed on a reversed phase octyl column by using a mobile phase consisting of sodium pentanesulfonate in 1% acetic acid-methanol-tetrahydrofuran under gradient elution conditions. The fluorescence intensity of pyridoxal 5'-phosphate was enhanced by post-column photochemical conversion, giving significantly different fluorescence spectra by a on-line photoreactor switched OFF and ON under irradiation at 254 nm. In addition, a simple and rapid method in isocratic conditions without the need of photochemical conversion was proposed for the analysis of Vitamin B 6 and Vitamin B 2 in pharmaceuticals. Linearity, precision, recovery, selectivity and sensitivity were found satisfactory for each analysed compound. Quantitation limits ranged from 26 to 240 fmol

  19. SIMA: Python software for analysis of dynamic fluorescence imaging data

    Patrick eKaifosh

    2014-09-01

    Full Text Available Fluorescence imaging is a powerful method for monitoring dynamic signals in the nervous system. However, analysis of dynamic fluorescence imaging data remains burdensome, in part due to the shortage of available software tools. To address this need, we have developed SIMA, an open source Python package that facilitates common analysis tasks related to fluorescence imaging. Functionality of this package includes correction of motion artifacts occurring during in vivo imaging with laser-scanning microscopy, segmentation of imaged fields into regions of interest (ROIs, and extraction of signals from the segmented ROIs. We have also developed a graphical user interface (GUI for manual editing of the automatically segmented ROIs and automated registration of ROIs across multiple imaging datasets. This software has been designed with flexibility in mind to allow for future extension with different analysis methods and potential integration with other packages. Software, documentation, and source code for the SIMA package and ROI Buddy GUI are freely available at http://www.losonczylab.org/sima/.

  20. Fluorescent analysis of interaction of flavonols with hemoglobin and bovine serum albumin

    Sentchouk, V. V.; Bondaryuk, E. V.

    2007-09-01

    We have studied the fluorescent properties of flavonols (quercetin, fisetin, morin, rutin) with the aim of studying possible interaction with hemoglobin and bovine serum albumin (BSA). We observed an increase in the intensity of intrinsic fluorescence for all the flavonols except rutin in the presence of BSA. From the changes in the fluorescence spectra, we concluded that tautomeric forms are formed on interaction with hemoglobin. We determined the interconnection between the structure of related flavonols and their fluorescent properties on interaction with proteins, and we determined the binding constants for binding with BSA and hemoglobin.

  1. Laser-Excited Atomic Fluorescence and Ionization in a Graphite Furnace for the Determination of Metals and Nonmetals

    Butcher, David James

    1990-01-01

    Here is reported novel instrumentation for atomic spectrometry that combined the use of a pulsed laser system as the light source and an electrothermal atomizer as the atom cell. The main goal of the research was to develop instrumentation that was more sensitive for elemental analysis than commercially available instruments and could be used to determine elements in real sample matrices. Laser excited atomic fluorescence spectrometry (LEAFS) in an electrothermal atomizer (ETA) was compared to ETA atomic absorption spectrometry (AAS) for the determination of thallium, manganese, and lead in food and agricultural standard reference materials (SRMs). Compared to ETA AAS, ETA LEAFS has a longer linear dynamic range (LDR) (5-7 orders of magnitude compared to 2-3 orders of magnitude) and higher sensitivity (10 ^{-16} to 10^{ -14} g as compared to 10^{ -13} to 10^{-11} g). Consequently, ETA LEAFS allows elemental analysis to be done over a wider range of concentrations with less dilution steps. Thallium was accurately determined in biological samples by ETA LEAFS at amounts five to one hundred times below the ETA AAS detection limit. ETA AAS and ETA LEAFS were compared for the determination of lead and manganese, and in general, the accuracies and precisions of ETA AAS were the same, with typical precisions between 3% and 6%. Fluorine was determined using laser excited molecular fluorescence spectrometry (LEMOFS) in an ETA. Molecular fluorescence from magnesium fluoride was collected, and the detection limit of 0.3 pg fluorine was two to six orders of magnitude more sensitive than other methods commonly used for the determination of fluorine. Significant interferences from ions were observed, but the sensitivity was high enough that fluorine could be determined in freeze dried urine SRMs by diluting the samples by a factor of one hundred to remove the interferences. Laser enhanced ionization (LEI) in an ETA was used for the determination of metals. For thallium, indium

  2. Rapid Simultaneous Amplification and Detection of the MBR/JH Chromosomal Translocation by Fluorescence Melting Curve Analysis

    Bohling, Sandra D.; King, Thomas C.; Wittwer, Carl T.; Elenitoba-Johnson, Kojo S. J.

    1999-01-01

    Polymerase chain reaction (PCR) amplification and product analysis for the detection of chromosomal translocations, such as the t(14;18), has traditionally been a two-step process. PCR product detection has generally entailed gel electrophoresis and/or hybridization or sequencing for confirmation of assay specificity. Using a microvolume fluorimeter integrated with a thermal cycler and a PCR-compatible double-stranded DNA (dsDNA) binding fluorescent dye (SYBR Green I), we investigated the feasibility of simultaneous thermal amplification and detection of MBR/JH translocation products by fluorescence melting curve analysis. We analyzed DNA from 30 cases of lymphoproliferative disorders comprising 19 cases of previously documented MBR/JH-positive follicle center lymphoma and 11 reactive lymphadenopathies. The samples were coded and analyzed blindly for the presence of MBR/JH translocations by fluorescence melting curve analysis. We also performed dilutional assays using the MBR/JH-positive cell line SUDHL-6. Multiplex PCR for MBR/JH and β-globin was used to simultaneously assess sample adequacy. All (100%) of the 19 cases previously determined to be MBR/JH positive by conventional PCR analysis showed a characteristic sharp decrease in fluorescence at ∼90°C by melting curve analysis after amplification. Fluorescence melting peaks obtained by plotting the negative derivative of fluorescence over temperature (−dF/dT) versus temperature (T) showed melting temperatures (Tm) at 88.85 ± 1.15°C. In addition, multiplex assays using both MBR/JH and β-globin primers yielded easily distinguishable fluorescence melting peaks at ∼90°C and 81.2°C, respectively. Dilutional assays revealed that fluorescence melting curve analysis was more sensitive than conventional PCR and agarose gel electrophoresis with ultraviolet transillumination by as much as 100-fold. Simultaneous amplification and fluorescence melting curve analysis is a simple, reliable, and sensitive method

  3. Development of Ratiometric Fluorescent Biosensors for the Determination of Creatine and Creatinine in Urine.

    Duong, Hong Dinh; Rhee, Jong Il

    2017-11-08

    In this study, the oxazine 170 perchlorate (O17)-ethylcellulose (EC) membrane was successfully exploited for the fabrication of creatine- and creatinine-sensing membranes. The sensing membrane exhibited a double layer of O17-EC membrane and a layer of enzyme(s) entrapped in the EC and polyurethane hydrogel (PU) matrix. The sensing principle of the membranes was based on the hydrolytic catalysis of urea, creatine, and creatinine by the enzymes. The reaction end product, ammonia, reacted with O17-EC membrane, resulting in the change in fluorescence intensities at two emission wavelengths ( λ em = 565 and 625 nm). Data collected from the ratio of fluorescence intensities at λ em = 565 and 625 nm were proportional to the concentrations of creatine or creatinine. Creatine- and creatinine-sensing membranes were very sensitive to creatine and creatinine at the concentration range of 0.1-1.0 mM, with a limit of detection (LOD) of 0.015 and 0.0325 mM, respectively. Furthermore, these sensing membranes showed good features in terms of response time, reversibility, and long-term stability. The interference study demonstrated that some components such as amino acids and salts had some negative effects on the analytical performance of the membranes. Thus, the simple and sensitive ratiometric fluorescent sensors provide a simple and comprehensive method for the determination of creatine and creatinine concentrations in urine.

  4. Chlorine determination in (U, Pu)C fuel by total reflection X-ray fluorescence spectrometry

    Misra, Nand Lal; Dhara, Sangita; Mudher, Khush Dev Singh; Aggarwal, Suresh K.; Thakur, Uday Kumar; Shah, Dipti; Sawant, R.M.; Ramakumar, K.L.

    2007-01-01

    A Total Reflection X-ray Fluorescence (TXRF) method for the determination of chlorine in (U,Pu)C has been developed. The method involves calibration of the instrument with standard solutions and validation of TXRF determination of chlorine using synthetic standard solutions. Cl K α line excited with W L α source was used for TXRF determinations of chlorine. Chlorine present in trace amounts in (U,Pu)C samples was first separated by pyro hydrolysis. The evolved chlorine, in form of HCl, was collected in 5 mM NaOH solution. This solution was analyzed for chlorine by Total Reflection X-ray Fluorescence Spectrometry using cobalt as an internal standard. The TXRF detection limit of chlorine was found to be 3.6 pg with sample size of 30 μL. In order to assess the applicability of TXRF method for chlorine determinations in other nuclear materials, one U 3 O 8 trace element standard was also analyzed for chlorine in similar way. The precision of the method was found to be 25% (1 σ) at ng level in most of the cases. (author)

  5. Determination of rubidium and strontium in geological materials by X-Ray fluorescence spectrometry

    Roca, M.

    1979-01-01

    In order to determine whole-rock ages by the Rb/Sr procedure, an X-ray fluorescence spectrometry method for the determination of both elements has been developed. The samples are pressed into boric acid backed and ringed pellets with this material as a binding agent. Matrix corrections are made following the determination od the mass absorption coefficients, based on the intensity of the Compton-scattered peak of MoKα. or MoKβ 1 .3. The U. S. Geological Survey granodiorite GSP-1 is used as a reference standard. Spectral-line interferences have been carefully studied and the empirical correction factors determined. A BASIC language program for calculating the Rb and Sr concentrations and the Rb/Sr ratios has been written. (Author) 7 refs

  6. The determination of trace elements in uranium ores by x-ray fluorescence spectrometry

    De Villiers, W. van Z.

    1983-11-01

    The determination of 17 trace elements (As, Ba, Co, Cr, Cu, Mo, Nb, Ni, Pb, Rb, Sr, Th, U, V, Y, Zn and Zr) in uranium ores by x-ray fluorescence spectrometry was investigated in this study. The determination of major elements was also necessary for the calculation of mass absorption coefficients. Initially a method was developed for the determination of the elements of interest in unmineralised silicates. Correction for absorption of radiation by the sample were made by means of mass absorption coefficients which were obtained from the relation between the inverse of the mass absorption coefficient and the intensity of the Compton scattering peak. The Feather and Willis method was used for determining the background intensity at the peak positions as well as for mass absorption coefficients. It was observed that the background intensity in the region of the uranium lines increases with increasing uranium content of the sample

  7. Determination of glutaredoxin enzyme activity and protein S-glutathionylation using fluorescent eosin-glutathione.

    Coppo, Lucia; Montano, Sergio J; Padilla, Alicia C; Holmgren, Arne

    2016-04-15

    Glutaredoxins catalyze glutathione-dependent disulfide oxidoreductions, particularly reduction of glutathione (GSH)-protein mixed disulfides. Mammalian glutaredoxins are present in the cytosol/nucleus as Grx1 or in mitochondria as Grx2a. Here we describe di-eosin-glutathione disulfide (Di-E-GSSG) as a new tool to study glutaredoxin (Grx) activity. Di-E-GSSG has almost no fluorescence in its disulfide form due to self-quenching, whereas the reduced form (E-GSH) has a large fluorescence emission at 545 nm after excitation at 520 nm. Di-E-GSSG was a very poor substrate for glutathione reductase, but we discovered that the molecule was an excellent substrate for glutaredoxin in a coupled assay system with GSH, nicotinamide adenine dinucleotide phosphate (NADPH), and glutathione reductase or with lipoamide, NADH, and lipoamide dehydrogenase. In addition, Di-E-GSSG was used to glutathionylate the free SH group of bovine serum albumin (BSA), yielding eosin-glutathionylated BSA (E-GS-BSA) readily observed in ultraviolet (UV) light. E-GS-BSA also displayed a quenched fluorescence, and its Grx-catalyzed reduction could be followed by the formation of E-GSH by fluorescence emission using microtiter plates. This way of measuring Grx activity provided an ultrasensitive method that detected Grx1 and Grx2 at picomolar levels. Human Grx1 was readily quantified in 40 μl of plasma and determined to be 680 ± 208 pM in healthy controls. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Radioactivation and X-ray fluorescence methods of determination of some elements in atmospheric air and waters

    Kulmatov, R.A.; Kist, A.A.; Karimov, I.I.; Pulatov, D.D.; Kamil'dzhanov, A.Kh.

    1981-01-01

    Possibilities of instrumental radioactivation and X-ray fluorescence method of determining certain elements in aerosols and waters in the region of metallurgic production location and around it are considered. For conducting instrumental radioactivation analysis the samples have been irradiated on filter during 20h in the thermal neutron flux f=10 13 neutr/cm 2 xs of nuclear reactor-WWR-SM INP ASUzSSR. Measurement of induced activity has been conducted after 7 and 15-day cooling by means of Ge(Li) detectors. Averaged results of instrumental radioactivation and X-ray fluorescence analysis of element (Cu, Zn, Fe, Pb) composifion of some samples are presented. Content of such elements as copper, zinc, lead in the industrial region several times exceeds usual background content that is caused by industrial releases. Toxic effect, rate of aerosol release from atmosphere and radius of harmful effect of industrial enterprises on environment much depends on dispersion. A set of filter materials differing from one another by pore diameter have been used for conducting dispersion analysis of aerosals [ru

  9. Elemental analysis of air particulate samples in Jakarta area by x-ray fluorescence spectrometry

    Yumiarti; Yusuf, M.; Mellawati, June; Menry, Yulizon; Surtipanti S

    1998-01-01

    Determination of elements in air particulate samples collected from Jakarta, especially from industrial area Pulo Gadung, also from residence, office, and recreation sites had been carried out. The samples collected periodically from August through December 1996. The elements were analyzed by X-ray fluorescence spectrometry method. Quantitative and qualitative analyses were done using QXAS AXIL (Quantitative X-ray Analysis System of x-ray Spectra by Iterative Least squares fitting) and QAES (Quantitative Analyses of Environmental Samples) package program. Results of the analyses showed that the content of heavy metal elements in air particulate samples from all areas studied were still below the maximum permissible concentration. (authors)

  10. Determination of Fission Products in Irradiated Fuel by X-Ray Fluorescence

    Mogensen, Mogens Bjerg; Als-Nielsen, Jens Aage; Andersen, Niels Hessel

    X-ray fluorescence i s a well e s t a b l i s h e d analytical tool for measuring elemental composition of fairly large (~ 5 cm2) "cold" samples. A version of t h i s technique has been developed for a n a l y s i s of radial d i s t r i b u t i o n of f i s s i o n products Xe, Cs and Ba...... in the scanning d i rection and 2 mm long. The measured Xe Ko x-ray i n t e n s i t i e s are converted to absolute concentrations by comparing to the intens i t y from a Xe gas standard. In the case of Cs and Ba s o l id standards may be used. The X-ray fluorescence analysis i s compared to other techniques used...... to obtain radial f i s s i o n product profiles, i t i s shown how a combination of X-ray fluorescence and electron probe micro a n a l y s i s i s able to reveal the amount of Xe in the grain boundary porosities....

  11. Laser-induced fluorescence with an OPO system. Part II: direct determination of lead content in seawater by electrothermal atomization-laser-excited atomic fluorescence (ETA-LEAF).

    Le Bihan, A; Lijour, Y; Giamarchi, P; Burel-Deschamps, L; Stephan, L

    2003-03-01

    Fluorescence was induced by coupling a laser with an optical parametric oscillator (OPO) to develop an analytical method for the direct determination of lead content, at ultra-trace level, in seawater by electrothermal atomization-laser-excited atomic fluorescence (ETA-LEAF). The optimization of atomization conditions, laser pulse energy, and mainly temporal parameters allowed us to reach a 3 fg detection limit (0.3 ng L(-1)) despite the low repetition rate of the device. The expected error on predicted concentrations of lead, at trace levels, in seawater was below 15%.

  12. Determinations of silicon and phosphorus in rice planted on a district of high incidence of amyotrophic lateral sclerosis by neutron activation and X-ray fluorescence analyses

    Mizumoto, Yoshihiko; Ishikawa, Teruumi; Kusakabe, Toshio; Katsurayama, Kousuke; Iwata, Shiro.

    1989-01-01

    Silicon and phosphorus contents in polished and unpolished rice planted on a district of high incidence of amyotrophic lateral sclerosis (ALS) have been determined by neutron activation and X-ray fluorescence methods, and compared with those from control areas. In the neutron activation analysis, β-ray spectra of 32 P produced by the 31 P(n, γ) 32 P reaction on polished and unpolished rice were measured with a low background β-ray spectrometer. In the X-ray fluorescence analysis, characteristic X-ray were analyzed with a wavelength dispersive X-ray fluorescence spectrometer. Silicon contents in polished and unpolished rice from the ALS area are 42 μg.g -1 and 370 μg.g -1 , respectively, and the corresponding phosphorus contents are 1210 μg.g -1 , and 3370 μg.g -1 , respectively. The data for ALS area are equal to those for the control area within atandard deviation. (author)

  13. X-ray fluorescence diffractionless analyzer for determining light element content in iron ore mixtures

    Yuksa, L.K.; Kochmola, N.M.; Bondarenko, V.P.; Bogdanov, V.K.

    1986-01-01

    Diffractionless X-ray fluorescence analyzer for detecting calcium oxide and silicon dioxide contents in dry iron ore materials has been developed. The analyzer includes a charging unit, sample-conveying device, spectrometric units for detecting calcium and silicon, computing racks and sample-removing device. Results of calcium oxide and silicon dioxide analyses in iron ore mixtures are presented. Errors are evaluated. It is shown that the analyzer provides high accuracy of one-time determinations, as well as reading constancy for a long time

  14. Determination of low concentrations of uranium in granite samples by X-ray fluorescence

    Roca, M.; Diaz-Guerra, J.P.

    1981-01-01

    An x-ray fluorescence method for the determination of uranium in granite samples for concentrations ranging from 3 to 100 ppm U 3 O 8 has been developed. To this purpose a sample holder, specially designed, allowing the irradiation of sample surfaces 42.5 mm in diameter and a molybdenum tube operating with a power of 2700 W (90 kV, 30 mA) are used. The background influence and the spectral interferences from rubidium and strontium have been taken into account and specific correction coefficients have been computed. A Basic program facilitates the report of the analytical results. (author)

  15. Fluorescent investigation of the interactions between N-(p-chlorophenyl)-N'-(1-naphthyl) thiourea and serum albumin: Synchronous fluorescence determination of serum albumin

    Cui Fengling [School of Chemistry and Environmental Science, Key Laboratory for Environmental Pollution Control Technology of Henan Province, Henan Normal University, Xinxiang, Hennan 453007 (China)]. E-mail: fenglingcui@hotmail.com; Wang Junli [School of Chemistry and Environmental Science, Key Laboratory for Environmental Pollution Control Technology of Henan Province, Henan Normal University, Xinxiang, Hennan 453007 (China); Cui Yanrui [School of Chemistry and Environmental Science, Key Laboratory for Environmental Pollution Control Technology of Henan Province, Henan Normal University, Xinxiang, Hennan 453007 (China); Li Jianping [School of Chemistry and Environmental Science, Key Laboratory for Environmental Pollution Control Technology of Henan Province, Henan Normal University, Xinxiang, Hennan 453007 (China)

    2006-07-07

    The interactions between N-(p-chlorophenyl)-N'-(1-naphthyl) thiourea and serum albumin were investigated by fluorescence spectroscopy and UV absorption spectrum under physiological conditions. The results of spectroscopic measurements suggested that N-(p-chlorophenyl)-N'-(1-naphthyl) thiourea should have a strong ability to quench the intrinsic fluorescence of both bovine serum albumin and human serum albumin through static quenching procedure, and the hydrophobic interaction was the predominant intermolecular force stabilizing the complex. Thermodynamic parameter enthalpy changes ({delta}H) and entropy changes ({delta}S) were calculated according to the Vant'Hoff equation. The binding distances between N-(p-chlorophenyl)-N'-(1-naphthyl) thiourea and the proteins were evaluated on the basis of the theory of Foester energy transfer. In addition, the effects of other ions on the binding constants of complexes were also discussed. Synchronous fluorescence technology was successfully applied to the determination of serum albumins added to the CPNT solution.

  16. Fluorescent investigation of the interactions between N-(p-chlorophenyl)-N'-(1-naphthyl) thiourea and serum albumin: Synchronous fluorescence determination of serum albumin

    Cui Fengling; Wang Junli; Cui Yanrui; Li Jianping

    2006-01-01

    The interactions between N-(p-chlorophenyl)-N'-(1-naphthyl) thiourea and serum albumin were investigated by fluorescence spectroscopy and UV absorption spectrum under physiological conditions. The results of spectroscopic measurements suggested that N-(p-chlorophenyl)-N'-(1-naphthyl) thiourea should have a strong ability to quench the intrinsic fluorescence of both bovine serum albumin and human serum albumin through static quenching procedure, and the hydrophobic interaction was the predominant intermolecular force stabilizing the complex. Thermodynamic parameter enthalpy changes (ΔH) and entropy changes (ΔS) were calculated according to the Vant'Hoff equation. The binding distances between N-(p-chlorophenyl)-N'-(1-naphthyl) thiourea and the proteins were evaluated on the basis of the theory of Foester energy transfer. In addition, the effects of other ions on the binding constants of complexes were also discussed. Synchronous fluorescence technology was successfully applied to the determination of serum albumins added to the CPNT solution

  17. Determination of cadmium in seawater by chelate vapor generation atomic fluorescence spectrometry

    Sun, Rui; Ma, Guopeng; Duan, Xuchuan; Sun, Jinsheng

    2018-03-01

    A method for the determination of cadmium in seawater by chelate vapor generation (Che-VG) atomic fluorescence spectrometry is described. Several commercially available chelating agents, including ammonium pyrrolidine dithiocarbamate (APDC), sodium dimethyl dithiocarbamate (DMDTC), ammonium dibutyl dithiophosphate (DBDTP) and sodium O,O-diethyl dithiophosphate (DEDTP), are compared with sodium diethyldithiocarbamate (DDTC) for the Che-VG of cadmium, and results showed that DDTC and DEDTP had very good cadmium signal intensity. The effect of the conditions of Che-VG with DDTC on the intensity of cadmium signal was investigated. Under the optimal conditions, 85 ± 3% Che-VG efficiency is obtained for cadmium. The detection limit (3σ) obtained in the optimal conditions was 0.19 ng ml- 1. The relative standard deviation (RSD, %) for ten replicate determinations at 2 ng ml- 1 Cd was 3.42%. The proposed method was successfully applied to the ultratrace determination of cadmium in seawater samples by the standard addition method.

  18. A novel method for iodate determination using cadmium sulfide quantum dots as fluorescence probes

    Tang Chunran; Su Zhonghua; Lin Baogang; Huang Haowen; Zeng Yunlong; Li Shuang; Huang He; Wang Yajing; Li Chunxiang; Shen Guoli; Yu Ruqin

    2010-01-01

    We have developed a novel method for the determination of iodate based on the carboxymethyl cellulose-capped CdS quantum dots (QDs). Factors affecting the iodate detection were investigated, and the optimum conditions were determined. Under the optimum conditions, the relative fluorescence intensity of CdS quantum dots was linearly proportional to IO 3 - over a concentration range from 1.0 x 10 -8 to 1.0 x 10 -5 mol L -1 with a correlation coefficient of 0.9987 and a detection limit of 6.0 nmol L -1 . Iodide, being oxidized by bromine to form iodate, was detected indirectly. The method was successfully applied to the determination of iodate and total amount of iodine in table salt samples. The related mechanism was also discussed.

  19. X-ray fluorescence analysis of archaeological finds and art objects: Recognizing gold and gilding

    Trojek, Tomáš; Hložek, Martin

    2012-01-01

    Many cultural heritage objects were gilded in the past, and nowadays they can be found in archeological excavations or in historical buildings dating back to the Middle Ages, or from the modern period. Old gilded artifacts have been studied using X-ray fluorescence analysis and 2D microanalysis. Several techniques that enable the user to distinguish gold and gilded objects are described and then applied to investigate artifacts. These techniques differ in instrumentation, data analysis and numbers of measurements. The application of Monte Carlo calculation to a quantitative analysis of gilded objects is also introduced. - Highlights: ► Three techniques of gilding identification with XRF analysis are proposed. ► These techniques are applied to gold and gilded art and archeological objects. ► Composition of a substrate material is determined by a Monte Carlo simulation.

  20. Establishment of an analytical procedure for the determination of niobium and tantalum in minerals containing these elements using X-ray fluorescence technique

    Nguyen Xuan Chien

    2003-01-01

    The study of determination of niobium, tantalum in mineral and tin slags using X-ray fluorescence spectrometry was carried out. Analytical samples of powder and pellet were prepared. the interference of the major accompanied elements in sample with the determination of niobium and tantalum was also studied. The analysis of niobium and tantalum in mineral and in tin slags samples was given in this work. (author)

  1. Determination of absolute Ba densities during dimming operation of fluorescent lamps by laser-induced fluorescence measurements

    Hadrath, S; Beck, M; Garner, R C; Lieder, G; Ehlbeck, J

    2007-01-01

    Investigations of fluorescent lamps (FL) are often focused on the electrodes, since the lifetime of the lamps is typically limited by the electrode lifetime and durability. During steady state operation, the work function lowering emitter material, in particular, barium, is lost. Greater barium losses occur under dimming conditions, in which reduced discharge currents lead to increased cathode falls, the result of the otherwise diminished heating of the electrode by the bombarding plasma ions. In this work the barium density near the electrodes of (FL), operating in high frequency dimming mode is investigated using the high-sensitivity method of laser-induced fluorescence. From these measurements we infer barium loss for a range of discharge currents and auxiliary coil heating currents. We show that the Ba loss can very easily be reduced by moderate auxiliary coil heating

  2. Analysis of kiwi fruit (Accented deliciosa) by energy dispersive X-ray fluorescence spectra

    Oliveira, Ana Claudia S.; Oliveira, Marcia L. de; Silva, Lucia C.A.S.; Arthur, Valter; Almeida, Eduardo

    2011-01-01

    The search for a healthy life has led consumers to eat fruits and vegetables in place of manufactured products, however, the demand for minimally processed products has evolved rapidly. The kiwi has at least eight nutrients beneficial to health: calcium, magnesium, manganese, phosphorus, iron, potassium, sodium and has also high vitamin C, which has wide acceptance in consumer markets. Energy dispersive spectroscopy X-ray (EDX) is the analytical technique used for elemental analysis or chemical characterization of a sample. It is a variant of fluorescence spectroscopy X-ray based on the sample through an investigation of interactions between electromagnetic radiation and matter, analyzing X-rays emitted by matter in response to being struck by charged particles. The aim of this study were to determine potassium, calcium, iron and bromine (K, Ca, Fe and Br, respectively) present in kiwifruit using the technique of fluorescence X-ray energy dispersive (EDXRF). Kiwifruit were peeled, washed and cut into slices and freeze-dried. After drying the sample was held digestion and subsequent reading of the same equipment in the X-ray fluorescence energy dispersive (EDXRF). The results indicated that the contents of potassium, calcium, iron and bromine are present in kiwifruit as expected when compared to Brazilian Table of Food Composition. (author)

  3. FLIMX: A Software Package to Determine and Analyze the Fluorescence Lifetime in Time-Resolved Fluorescence Data from the Human Eye.

    Matthias Klemm

    Full Text Available Fluorescence lifetime imaging ophthalmoscopy (FLIO is a new technique for measuring the in vivo autofluorescence intensity decays generated by endogenous fluorophores in the ocular fundus. Here, we present a software package called FLIM eXplorer (FLIMX for analyzing FLIO data. Specifically, we introduce a new adaptive binning approach as an optimal tradeoff between the spatial resolution and the number of photons required per pixel. We also expand existing decay models (multi-exponential, stretched exponential, spectral global analysis, incomplete decay to account for the layered structure of the eye and present a method to correct for the influence of the crystalline lens fluorescence on the retina fluorescence. Subsequently, the Holm-Bonferroni method is applied to FLIO measurements to allow for group comparisons between patients and controls on the basis of fluorescence lifetime parameters. The performance of the new approaches was evaluated in five experiments. Specifically, we evaluated static and adaptive binning in a diabetes mellitus patient, we compared the different decay models in a healthy volunteer and performed a group comparison between diabetes patients and controls. An overview of the visualization capabilities and a comparison of static and adaptive binning is shown for a patient with macular hole. FLIMX's applicability to fluorescence lifetime imaging microscopy is shown in the ganglion cell layer of a porcine retina sample, obtained by a laser scanning microscope using two-photon excitation.

  4. FLIMX: A Software Package to Determine and Analyze the Fluorescence Lifetime in Time-Resolved Fluorescence Data from the Human Eye.

    Klemm, Matthias; Schweitzer, Dietrich; Peters, Sven; Sauer, Lydia; Hammer, Martin; Haueisen, Jens

    2015-01-01

    Fluorescence lifetime imaging ophthalmoscopy (FLIO) is a new technique for measuring the in vivo autofluorescence intensity decays generated by endogenous fluorophores in the ocular fundus. Here, we present a software package called FLIM eXplorer (FLIMX) for analyzing FLIO data. Specifically, we introduce a new adaptive binning approach as an optimal tradeoff between the spatial resolution and the number of photons required per pixel. We also expand existing decay models (multi-exponential, stretched exponential, spectral global analysis, incomplete decay) to account for the layered structure of the eye and present a method to correct for the influence of the crystalline lens fluorescence on the retina fluorescence. Subsequently, the Holm-Bonferroni method is applied to FLIO measurements to allow for group comparisons between patients and controls on the basis of fluorescence lifetime parameters. The performance of the new approaches was evaluated in five experiments. Specifically, we evaluated static and adaptive binning in a diabetes mellitus patient, we compared the different decay models in a healthy volunteer and performed a group comparison between diabetes patients and controls. An overview of the visualization capabilities and a comparison of static and adaptive binning is shown for a patient with macular hole. FLIMX's applicability to fluorescence lifetime imaging microscopy is shown in the ganglion cell layer of a porcine retina sample, obtained by a laser scanning microscope using two-photon excitation.

  5. Determination of heavy metals in Damascus drinking water using total reflection x-ray fluorescence

    Bakraji, E. H.; Karajo, J.

    2000-01-01

    Total reflection x-ray fluorescence spectrometry and chemical preconcentration have applied for multi-elemental analysis of Damascus drinking water. Water was taken directly from taps of several city sectors and analyzed for the following trace elements: Ti, V, Cr, Fe, Co, Ni, Cu, Zn, Se and Pb. The detection limits were found to be in the range of 0.1 to 0.4 μg/l. The mean levels of trace elements in the Damascus drinking water were below the World Health Organization drinking water quality guidelines. (author)

  6. X-Ray Fluorescence Spectrometry. II. Determination of Uranium in ores

    Bermudez Polonio, J.; Crus Castillo, F. de la; Fernandez Cellini, R.

    1961-01-01

    A method of analysis of uranium in ores by X-ray spectrometry was developed, using the internal standard technique. Strontium was found to be the most suitable internal standard for general use. A Norelco Philips X-ray fluorescent spectrometer was used in this work, equipped with a lithium fluoride crystal acting as a diffraction grating analyzer. The intensity of the uranium-L α 1 spectral line is calculated and related to corresponding strontium-K α spectral line, both detected with a Scintillation Counter. (Author) 31 refs

  7. Critical aggregates concentration of fatty esters present in biodiesel determined by turbidity and fluorescence.

    Froehner, Sandro; Sánez, Juan; Dombroski, Luiz Fernando; Gracioto, Maria Paula

    2017-09-01

    Biodiesel for combustible engine is available as mixture of fossil diesel and fatty esters obtained by transesterification of vegetable oils. The use of biodiesel reduces the amount of SO x , mainly. However, it was already observed that biodiesel has a different behavior in environment in cases of accidental spill and groundwater contamination. It was noticed that the biodegradation of hydrocarbons (cyclic and aliphatic) in the presence of biodiesel are speeded, although the mechanism is still unclear. Considering the chemical structure of fatty esters, it was investigated the formation of aggregates in water solution by fatty esters present in commercial biodiesel. In Brazil, biodiesel is composed by 95% of fossil diesel and 5% of fatty esters mixture. In this work, fatty esters were treated as neutral surfactant, i.e., it was treated as a molecule with polar and non-polar part. Turbidity and fluorescence were used to determine the critical aggregates concentration (CAC). Water solutions containing fatty esters were examined exploiting changes in turbidity and fluorescence intensity of pyrene. Abrupt changes were attributed to aggregates formation, following the same behavior of traditional amphiphilic compounds. It was determined the CAC for ethyl palmitate, ethyl stearate, ethyl oleate, and ethyl linoleate. The values of CAC for fatty esters varied from 1.91 to 4.27 μmol/L, while CAC for the mixture of esters (biodiesel) was 2.01 for methyl esters and 1.19 for ethyl esters, both prepared using soybean oil. The aggregates formation was also determined by fluorescence measurements considering the changes in intensity of peaks I and III of pyrene. Pyrene senses the changes in environment polarity. The values found of CAC by fluorescence for individual ethyl esters varied from 1.85 to 3.21 μmol/L, while mixtures of ethyl esters was 2.23 and 2.07 μmol/L for mixture of methyl esters. The results clearly showed that fatty esters form aggregates and might be

  8. Radioisotope sources for X-ray fluorescence analysis

    Leonowich, J.; Pandian, S.; Preiss, I.L.

    1977-01-01

    Problems involved in developing radioisotope sources and the characteristics of potentially useful radioisotopes for X-ray fluorescence analysis are presented. These include the following. The isotope must be evaluated for the physical and chemical forms available, purity, half-life, specific activity, toxicity, and cost. The radiation hazards of the source must be considered. The type and amount of radiation output of the source must be evaluated. The source construction must be planned. The source should also present an advance over those currently available in order to justify its development. Some of the isotopes, which are not in use but look very promising, are indicated, and their data are tabulated. A more or less ''perfect'' source within a given range of interest would exhibit the following characteristics. (1) Decay by an isometric transition with little or no internal conversion, (2) Have an intense gamma transition near the absorption edge of the element(s) of interest with no high energy gammas, (3) Have a sufficiently long half-life (in the order of years) for both economic and calibration reasons, (4) Have a sufficiently large cross-section for production in a reasonable amount of time. If there are competing reactions the interfering isotopes should be reasonably short-lived, or if not, be apt to be separated from the isotope chemically with a minimum of difficulty. (T.G.)

  9. Study of granitic biotites by X-ray fluorescence analysis: determination of iron, manganese, titanium, calcium, potassium, silicon and aluminium; Estudio de biotitas graniticas por fluorescencia de rayos X: Determinacion de hierro, manganeso, titanio, calcio, potasio, silicio y aluminio

    Toubes, R. O.; Bermudez Polonio, J.

    1968-07-01

    A method for the quantitative determination of iron, manganese, titanium, calcium potassium, silicon, and aluminium, is reported, Sample preparation is carried out by the miniature flux technique, and rubidium is used as internal standard for silicon and aluminium. (Author) 5 refs.

  10. A comparison of the performance of a fundamental parameter method for analysis of total reflection X-ray fluorescence spectra and determination of trace elements, versus an empirical quantification procedure

    W(egrzynek, Dariusz; Hołyńska, Barbara; Ostachowicz, Beata

    1998-01-01

    The performance has been compared of two different quantification methods — namely, the commonly used empirical quantification procedure and a fundamental parameter approach — for determination of the mass fractions of elements in particulate-like sample residues on a quartz reflector measured in the total reflection geometry. In the empirical quantification procedure, the spectrometer system needs to be calibrated with the use of samples containing known concentrations of the elements. On the basis of intensities of the X-ray peaks and the known concentration or mass fraction of an internal standard element, by using relative sensitivities of the spectrometer system the concentrations or mass fractions of the elements are calculated. The fundamental parameter approach does not require any calibration of the spectrometer system to be carried out. However, in order to account for an unknown mass per unit area of a sample and sample nonuniformity, an internal standard element is added. The concentrations/mass fractions of the elements to be determined are calculated during fitting a modelled X-ray spectrum to the measured one. The two quantification methods were applied to determine the mass fractions of elements in the cross-sections of a peat core, biological standard reference materials and to determine the concentrations of elements in samples prepared from an aqueous multi-element standard solution.

  11. Hyphenating multisyringe flow injection lab-on-valve analysis with atomic fluorescence spectrometry for on-line bead-injection preconcentration and determination of trace levels of hydride-forming elements in environmental samples

    Long, Xiangbao; Miró, Manuel; Hansen, Elo Harald

    2006-01-01

    the determination of ultratrace level concentrations of total inorganic arsenic in freshwater. Employing quantitative preoxidation of As(III) to As(V) in the samples by means of permanganate, the method involves the preconcentration of arsenate at pH 10 on a renewable anion exchanger, namely Q-Sepharose, packed...

  12. Sedimentation separation and fluorescent X-ray analysis of very small amount of cobalt in pure iron

    Kato, Kensaku

    1990-01-01

    As the simple method of separation and analysis of very small amount of cobalt up to 1 ppm in pure iron, the application of sedimentation separation and fluorescent X-ray analysis was examined. By adding citric acid to the sample solution, the masking of the main components was carried out, and cobalt was deposited with 2-nitroso 1-naphtol separated and concentrated on a membrane filter. The reagents and equipments used are shown. The operation of the fundamental quantitative determination was determined. The condition of measurement, the condition of sedimentation separation, the effect of coexisting elements, the rate of recovery of cobalt, the calibration curve, and the analysis of actual samples are reported. By separating and concentrating cobalt on a membrane filter, this method eliminates the obstruction of coexisting elements to the object element, which is the problem in fluorescent X-ray measurement, and has the merit of simple operation and wide range of quantitative determination. (K.I.)

  13. Determination of the activity of telomerase in cancer cells by using BSA-protected gold nanoclusters as a fluorescent probe.

    Xu, Yujuan; Zhang, Peng; Wang, Zhen; Lv, Shaoping; Ding, Caifeng

    2018-02-27

    Gold nanoclusters (AuNCs) protected with a bovine serum albumin (BSA) coating are known to emit red fluorescence (peaking at 650 nm) on photoexcitation with ultraviolet light (365 nm). On addition of Cu(II) ions, fluorescence is quenched because Cu(II) complexes certain amino acid units in the BSA chain. Fluorescence is, however, restored if pyrophosphate (PPi) is added because it will chelate Cu(II) and remove it from the BSA coating on the AuNCs. Because PPi is involved in the function of telomerase, the BSA@AuNCs loaded with Cu(II) can act as a fluorescent probe for determination of the activity of telomerase. A fluorescent assay was worked out for telomerase that is highly sensitive and has a wide linear range (10 nU to 10 fM per mL). The fluorescent probe was applied to the determination of telomerase activity in cervix carcinoma cells via imaging. It is shown that tumor cells can be well distinguished from normal cells by monitoring the differences in intracellular telomerase activity. Graphical abstract Gold nanoclusters (AuNCs) protected by bovine serum albumin (BSA) and displaying red photoluminescence were prepared as fluorescent probe for the determination of telomerase activity and used for imaging of cervix carcinoma (HeLa) cells.

  14. Comparison of fluorescence-enhancing reagents and optimization of laser fluorimetric technique for the determination of dissolved uranium

    Ceren Kuetahyali; Joaquin Cobos; Rondinella, V.V.

    2011-01-01

    Results from tests aimed at optimizing an instrumental procedure for the direct and fast determination of uranium in solution by laser fluorescence are presented. A comparison of sample fluorescence measured using different fluorescence enhancing reagents was performed: sodium pyrophosphate, orthophosphoric acid, sulphuric acid and a commercially available fluorescence enhancer were tested for the determination of uranium. From the experimental results, 0.01 M Na 4 P 2 O 7 x 10H 2 O showed the best performance. Effects of reagent pH, different matrices, different concentrations of dissolved Th, and sample volume were investigated. Applications of the improved procedure for the determination of uranium in samples arising from UO 2 -based high level nuclear waste dissolution studies are described. (author)

  15. The Determination of Composite Elements in Zircaloy-2 by X-Ray Fluorescence and Emission Spectrometry Method

    Dian Anggraini; Rosika Kriswarini; Yusuf N

    2007-01-01

    Analysis of composing elements in zircaloy-2 has been done by Emission Spectrometry method and X-Ray Fluorescence (XRF). The aim of the analysis is to verify conformity between composing elements in zircaloy-2 and the material certificate. Spectrometry Emission method has higher sensitivity in element determination of a material than that of XRF method, so can be estimated that emission spectrometry method has higher accuracy than that of XRF method. The result of qualitative analysis by Emission Spectrometry indicate that the composing elements in zircaloy-2 were Sn, Cr and Ni. However, the qualitative analysis result by XRF method indicated that the composing elements in zircaloy 2 were Sn, Cr, Ni and Fe. Fe element can not be analysed by Emission Spectrometry method because Emission Spectrometer did not equipped with Fe detector. The quantitative analysis result of the composing elements in the material with both methods showed that Sn, Cr and Ni concentration of zircaloy 2 existed in concentration ranges of the material certificate. Result of statistical test (F and t-test) of analysis result of both methods can be used for analyzing composing elements in zircaloy 2. Emission Spectrometry method was more sensitive and accurate for determining Cr and Ni element in zircaloy 2 than that of emission Spectrometry method but both methods had same accuracy. The precision of measurement of Sn, Cr and Ni element using XRF method was better than that of Emission spectrometry method. (author)

  16. X-ray structure determination, Hirshfeld surface analysis, spectroscopic (FT-IR, NMR, UV-Vis, fluorescence), non-linear optical properties, Fukui function and chemical activity of 4‧-(2,4-dimethoxyphenyl)-2,2‧:6‧,2″-terpyridine

    Demircioğlu, Zeynep; Yeşil, Ahmet Emin; Altun, Mehmet; Bal-Demirci, Tülay; Özdemir, Namık

    2018-06-01

    The compound 4‧-(2,4-dimethoxyphenyl)-2,2‧:6‧,2″-terpyridine (Mtpyr) was synthesized and investigated using X-ray single crystal structure determination, combined with Hirshfeld topology analysis of the molecular packing. In addition, Mtpyr was characterized by experimental and theoretical FT-IR, UV-Vis, 1H NMR, 13C NMR and fluorescence emission spectra. The optimized molecular geometry (bond length, bond angle, torsion angle), the complete vibrational frequency and all other theoretical computations were calculated by using density functional theory (DFT) B3LYP method with the help of 6-311++G(d,p) basis set. From the recorded UV-Vis spectrum, the electronic properties such as excitation energies, wavelength and oscillator strength are evaluated by TD-DFT in chloroform solution. The 1H and 13C nuclear magnetic resonance (NMR) chemical shifts of the molecule were calculated by the gauge-independent atomic orbital (GIAO) method and compared with experimental results. The calculated HOMO-LUMO band gap energies confirmed that charge transfer and chemical stability within the molecule. The hyperconjugative interaction energy E(2) and electron densities of donor (i) and acceptor (j) bonds were calculated using natural bond orbital (NBO) analysis. Besides Mulliken and natural population charges (NPA), non-linear optic properties (NLO), Fukui Function analysis, molecular electrostatic potential (MEP) were also computed which helps to identifying the electrophilic/nucleophilic nature.

  17. TRANES analysis of the fluorescence of nile red in organized ...

    Unknown

    Department of Chemical Sciences, Tata Institute of Fundamental Research, ... Construction of time-resolved emission spectra (TRES) is a useful method 1. If the ..... 1992–2000 Topics in fluorescence spectroscopy (New York: Plenum) vol. 1–5 ...

  18. Colouration of medieval glass bracelets studied by total reflection x-ray fluorescence analysis

    Detcheva, Albena; Velinova, Ralitsa; Ivanova, Elisaveta; Jordanov, Juri; Karadjov, Metody

    2014-01-01

    The contents of 3d-transition metals (Ti, V, Cr, Mn, Fe, Co, Ni, Cu and Zn) in fragments of medieval glass bracelets, found in the necropolis of Stambolovo and the castle of Mezek, Bulgaria, were determined by total reflection X-ray fluorescence (TXRF) analysis using gallium as internal standard. The samples were analysed as slurries in Triton X 114. The experimental parameters: grain size of the glass sample, concentrations of glass sample, Triton X114 and internal standard in the slurry, volume of the slurry aliquot taken for analysis, as well as the excitation time, were optimised. For method validation the certified reference material BAM-S005 Type A soda-lime glass was used. It was proven that the elements Co, Mn and Fe are responsible for colour generation in the investigated glass samples. The precision of the determinations is characterised by an RSD in the range 3–11%

  19. Energy-dispersive X-ray fluorescence analysis of organic-rich soils and sediments

    Parekh, P.P.

    1981-01-01

    A method has been developed for elemental analysis of environmental samples of soils and sediments rich in organic matter by energy-dispersive X-ray fluorescence spectrometry. It consists of three steps (i) determining the apparent concentration of elements by using calibration coefficients based on geochemical standards, (ii) subsequent assay of the total organic matter (TOM) from loss on ignition at 550 deg C, and (iii) evaluating the correct elemental concentration by normalizing for transparency from an empirical relationship. The main feature of the method is the sample analysis prior to ignition, which avoids any loss of trace elements - especially the volatile toxic elements, such as Zn, As, Se, and Pb - during heating. The method was tested on two organic-rich lake sediments (TOM> 30%). Concentrations of five elements (K, Mn, Fe, Zn, and Pb) determined by the present method and by atomic absorption spectrometry agreed within about +-10%. (author)

  20. [Determination of emamectin benzoate residue in vegetables by high performance liquid chromatography with fluorescence detection].

    Zhang, Yan; Wu, Yinliang; Hu, Jiye; Wang, Hongwei; Pan, Canping; Liu, Fengmao

    2008-01-01

    A method was developed for the determination of emamectin benzoate residue in cabbage and mushroom using solid-phase extraction (SPE) and high performance liquid chromatography (HPLC) with fluorescence detection. The sample was extracted with ethyl acetate. Further cleanup was performed on a propylsulfonic acid solid phase extraction cartridge, followed by the derivatization with trifluoroacetic anhydride in the presence of N-methylimidazole. The amount of derivatized emamectin benzoate was determined by fluorescence detector after separation by HPLC. The detection limit was 0.10 microg/kg for cabbage and mushroom samples. The recoveries of emamectin benzoate in cabbage and mushroom samples were 78.6%-84.9%. The inter-day relative standard deviation (RSD) and intra-day RSD were 2.7%-6.0% and 3.1%-8.9%, respectively, at the fortified levels of 1.0-20.0 microg/kg. The calibration curve of emamectin benzoate in vegetables at the concentration range of 0.002 mg/L to 0.10 mg/L was linear (r = 0.9999).

  1. Determination of nuclear spins of short-lived isotopes by laser induced fluorescence

    Buchinger, F.; Dabkiewicz, P.; Kremmling, H.; Kuehl, T.; Mueller, A.C.; Schuessler, H.A.

    1980-01-01

    The spins of several nuclear ground and isomeric states have been measured for a number of mercury isotopes. The fluorescent light from the 6s6p 3 P 1 state is observed at 2537 Angstroem after excitation with the frequency doubled output of a pulsed dye laser. Four different laser induced fluorescence techniques were tested for their applicability: double resonance, Hanle effect, time delayed integral Hanle beats, and time resolved quantum beats. The sensitivity and selectivity of these models are compared with emphasis on the determination of spins of nuclei far from beta-stability, where short half lives and low production yields restrict the number of available atoms. The experiments were carried out on-line with the ISOLDE isotope separator at CERN at densities as low as 10 6 atoms/cm 3 . Results for the very neutron deficient high spin mercury isomers with half lives of several seconds, but also for the ground states of the abundant low spin stable mercury isotopes, are given as examples. The test measurements determined the nuclear spins of the odd sup(185m-191m)Hg isomers to be I = 13/2. (orig.)

  2. Advances in low atomic number element analysis by wavelength dispersive x-ray fluorescence spectrometry

    Vrebos, B.

    1996-01-01

    Traditionally, the analysis of low atomic number has been a chal1enging task for wavelength dispersive x-ray fluorescence spectrometry. Among the most important factors influencing analysis of the low atomic number elements (from Z=11 downwards) are the fluorescence yield, absorption and the dispersion. The effect of each of these factors on the overall performance will be illustrated. The long wavelengths involved (longer than I nm) used to pose severe problems concerning the monochromator used. Early instruments relied on lead stearate or Blodgett Langmuir soap films for the diffraction of the characteristic radiation. Nowadays, synthetic multilayers are commonly used. The performance of these multilayers is determined by the reflectivity, the resolution and the absorption of the characteristic radiation to be diffracted. These parameters can be optimised by adequately selecting the composition of the materials involved. The sensitivity of the modem instruments is sufficient to allow quantitative analysis. However, this aspect of WDS XRF is still met with considerable scepticism. Examples of quantitative analysis will be given to illustrate the current capability

  3. Determination of Ti, Cr, Cu and Ta in niobium oxide by X-ray fluorescence method

    Dixit, R.M.; Deshpande, S.S.

    1986-01-01

    An x-ray fluorescence method for the determination of Ti, Cr, Cu and Ta in niobium oxide has been developed. Samples/standards in powder form are mixed with boric acid in the proportion of 1:1 (400 mg. each). Double layer pellets are prepared by pressing this mixture over a primary boric acid pellet. Philips PW-1220, a semiautomatic x-ray spectrometer with tungsten target x-ray tube for excitation and LiF (200) crystal for dispersion have been used. The determination range is from 0.005 to 0.1per cent for Ti and Cr, 0.01 to 0.1per cent for Cu and 0.05 to 1per cent for Ta. (author)

  4. Determination of the ruminant origin of bone particles using fluorescence in situ hybridization (FISH).

    Lecrenier, M C; Ledoux, Q; Berben, G; Fumière, O; Saegerman, C; Baeten, V; Veys, P

    2014-07-17

    Molecular biology techniques such as PCR constitute powerful tools for the determination of the taxonomic origin of bones. DNA degradation and contamination by exogenous DNA, however, jeopardise bone identification. Despite the vast array of techniques used to decontaminate bone fragments, the isolation and determination of bone DNA content are still problematic. Within the framework of the eradication of transmissible spongiform encephalopathies (including BSE, commonly known as "mad cow disease"), a fluorescence in situ hybridization (FISH) protocol was developed. Results from the described study showed that this method can be applied directly to bones without a demineralisation step and that it allows the identification of bovine and ruminant bones even after severe processing. The results also showed that the method is independent of exogenous contamination and that it is therefore entirely appropriate for this application.

  5. CdTe/ZnS quantum dots as fluorescent probes for ammonium determination.

    Yi, Kui-Yu

    2016-06-01

    Novel CdTe/ZnS quantum dot (QD) probes based on the quenching effect were proposed for the simple, rapid, and specific determination of ammonium in aqueous solutions. The QDs were modified using 3-mercaptopropionic acid, and the fluorescence responses of the CdTe/ZnS QD probes to ammonium were detected through regularity quenching. The quenching levels of the CdTe/ZnS QDs and ammonium concentration showed a good linear relationship between 4.0 × 10(-6) and 5.0 × 10(-4) mol/L; the detection limit was 3.0 × 10(-7) mol/L. Ammonium contents in synthetic explosion soil samples were measured to determine the practical applications of the QD probes and a probable quenching mechanism was described. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

  6. Pigment particles analysis with a total reflection X-ray fluorescence spectrometer: study of influence of instrumental parameters

    Coccato, Alessia; Vandenabeele, Peter [Ghent University, Department of Archaeology, Ghent (Belgium); Vekemans, Bart; Vincze, Laszlo; Moens, Luc [Ghent University, Department of Analytical Chemistry, Ghent (Belgium)

    2016-12-15

    Total reflection X-ray fluorescence (TXRF) analysis is an excellent tool to determine major, minor and trace elements in minuscule amounts of samples, making this technique very suitable for pigment analysis. Collecting minuscule amounts of pigment material from precious works of art by means of a cotton swab is a well-accepted sampling method, but poses specific challenges when TXRF is to be used for the characterization of the unknown material. (orig.)

  7. Analysis of metals in organic compounds by energy dispersive X-ray fluorescence analysis

    Anjos, Marcelino J.; Lopes, Ricardo T.; Jesus, Edgar F.O. de

    2000-01-01

    Using energy dispersive X-ray fluorescence analysis with an X-ray tube filtered with Ti. It was possible to determine the concentration of the elements at ppm level of several elements: K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn As, Rb, Sr, Y, Zr, and Pb in two types of organic compound enough used in the agriculture: organic compound of urban garbage (Fertilurb) and aviary bed (birds manure). The experimental setup is composed of: x-ray tube (Oxford, 30 kV, 50 μA and W anode), an ORTEC Si-Li detector, with an energy resolution of about 180 eV at 5.9 keV and an ORTEC multichannel-analyser. The X-ray beam is quasi- monochromatic by using Ti filter. The samples were prepared in pellet form with superficial density in the range of 100 mg/cm 2 . The fundamental parameter method was used in order to verify the elemental concentration. The radiation transmission method was going used to the radiation absorption effects correction in the samples. (author)

  8. Synchrotron x-ray fluorescence and extended x-ray absorption fine structure analysis

    Chen, J.R.; Gordon, B.M.; Hanson, A.L.; Jones, K.W.; Kraner, H.W.; Chao, E.C.T.; Minkin, J.A.

    1984-01-01

    The advent of dedicated synchrotron radiation sources has led to a significant increase in activity in many areas of science dealing with the interaction of x-rays with matter. Synchrotron radiation provides intense, linearly polarized, naturally collimated, continuously tunable photon beams, which are used to determine not only the elemental composition of a complex, polyatomic, dilute material but also the chemical form of the elements with improved accuracy. Examples of the application of synchrotron radiation include experiments in synchrotron x-ray fluorescence (SXRF) analysis and extended x-ray absorption fine structure (EXAFS) analysis. New synchrotron radiation x-ray microprobes for elemental analysis in the parts per billion range are under construction at several laboratories. 76 references, 24 figures

  9. Determination of the mass attenuation coefficients for X-ray fluorescence measurements correction by the Rayleigh to Compton scattering ratio

    Conti, C.C., E-mail: ccconti@ird.gov.br [Institute for Radioprotection and Dosimetry – IRD/CNEN, Rio de Janeiro (Brazil); Physics Institute, State University of Rio de Janeiro – UERJ, Rio de Janeiro (Brazil); Anjos, M.J. [Physics Institute, State University of Rio de Janeiro – UERJ, Rio de Janeiro (Brazil); Salgado, C.M. [Nuclear Engineering Institute – IEN/CNEN, Rio de Janeiro (Brazil)

    2014-09-15

    Highlights: •This work describes a procedure for sample self-absorption correction. •The use of Monte Carlo simulation to calculate the mass attenuation coefficients curve was effective. •No need for transmission measurement, saving time, financial resources and effort. •This article provides de curves for the 90° scattering angle. •Calculation on-line at (www.macx.net.br). -- Abstract: X-ray fluorescence technique plays an important role in nondestructive analysis nowadays. The development of equipment, including portable ones, enables a wide assortment of possibilities for analysis of stable elements, even in trace concentrations. Nevertheless, despite of the advantages, one important drawback is radiation self-attenuation in the sample being measured, which needs to be considered in the calculation for the proper determination of elemental concentration. The mass attenuation coefficient can be determined by transmission measurement, but, in this case, the sample must be in slab shape geometry and demands two different setups and measurements. The Rayleigh to Compton scattering ratio, determined from the X-ray fluorescence spectrum, provides a link to the mass attenuation coefficient by means of a polynomial type equation. This work presents a way to construct a Rayleigh to Compton scattering ratio versus mass attenuation coefficient curve by using the MCNP5 Monte Carlo computer code. The comparison between the calculated and literature values of the mass attenuation coefficient for some known samples showed to be within 15%. This calculation procedure is available on-line at (www.macx.net.br)

  10. Quantitative analysis of thorium in the presence of rare earth by X-ray fluorescence spectrometry

    Jesus, Camila S. de; Taam, Isabel; Vianna, Claudio A.

    2013-01-01

    The occurrence of Thorium in ores is normally associated to other elements such as Uranium and Cerium, as well as some Rare-Earths (RE). The separation of these elements by traditional analytic chemistry techniques is both time and reagent consuming, thus increasing the analysis cost. The hereby proposed method consists in the direct determination of Thorium in rare earths ores and compounds by X-ray fluorescence spectroscopy without any prior chemical separation from other matrix elements. This non-destructive technique is used to determine which elements are present in solid and liquid samples, as well as their concentrations. The studied matrix contains Lanthanum, Cerium, Praseodymium, Neodymium, Samarium, Gadolinium and Yttrium. This study evaluated the analytical lines of radiation emission for each rare earth contained in the matrix, comparing it to the Thorium main analytical line. The Thorium quantification was measured through the Th L line, where there is no influence or interference from the rare earths analytical lines. The studied samples are certified standards and the obtained results have been compared to Ethylenediaminetetraacetic acid (EDTA) titration results, an already well-established and widely trusted method. We also measured the matrix effect thus using complex rare earths liquor. This liquor contains also elements commonly found in monazites sands: phosphates, aluminum, iron. Obtained results state the efficiency of X-ray Fluorescence to determine Thorium in the presence of rare earths without any prior chemical separation. (author)

  11. Determination of trace aluminum by fluorescence quenching method based on catalysis of potassium chlorate oxidizing alizarin red

    Shao-Qin, Lin; Xuan, Lin; Shi-Rong, Hu; Li-Qing, Zeng; Yan, Wang; Li, Chen; Jia-Ming, Liu; Long-Di, Li

    2005-11-01

    A new method for the determination of trace aluminum has been proposed. It is based on the fact that alizarin red can emit strong and stable fluorescence at 80 °C for 30 min and Al 3+ can effectively catalyze potassium chlorate oxidizing alizarin red to form non-fluorescence complex which cause the fluorescence quenching. The linear dynamic range of this method is 0.040-4.00 ng l -1 with a detection limit of 5.3 pg l -1. The regression equation can be expressed as Δ If = 8.731 + 21.73 c (ng l -1), with the correlation coefficient r = 0.9992 ( n = 6). This sensitive, rapid and accurate method has been applied to the determination of trace aluminum(III) in human hair and tea samples successfully. What is more, the mechanism of catalyzing potassium chlorate oxidizing alizarin red by the fluorescence quenching method is also discussed.

  12. A coumarin-based "turn-on" fluorescent sensor for the determination of Al3+: single crystal X-ray structure and cell staining properties.

    Guha, Subarna; Lohar, Sisir; Sahana, Animesh; Banerjee, Arnab; Safin, Damir A; Babashkina, Maria G; Mitoraj, Mariusz P; Bolte, Michael; Garcia, Yann; Mukhopadhyay, Subhra Kanti; Das, Debasis

    2013-07-28

    An efficient Al(3+) receptor, 6-(2-hydroxybenzylideneamino)-2H-chromen-2-one (HBC), has been synthesized by condensing salicylaldehyde with 6-aminocoumarin. The molecular structure of HBC has been determined by a single crystal X-ray analysis. It was established that in the presence of Al(3+), HBC shows 25 fold enhancement of fluorescence intensity which might be attributed to the chelation-enhanced fluorescence (CHEF) process. HBC binds Al(NO3)3 in a 1 : 1 stoichiometry with a binding constant (K) of 7.9 × 10(4) M(-1). Fe(3+) and Mn(2+) quench the emission intensity of the [HBC + Al(3+)] system to an insignificant extent at a concentration 10 times higher compared to that of Al(3+). HBC is highly efficient in the detection of intracellular Al(3+) under a fluorescence microscope.

  13. Application of x-ray fluorescence (XRF) absolute analysis method for silica refractories

    Asakura, Hideo; Yamada, Yasujiro; Kansai, Kouhei; Tomatsu, Ichirou; Murata, Mamoru

    2015-01-01

    X-ray fluorescence (XRF) analysis is a rapid and precise quantitative analytical method for the determination of major and trace elements in many industries and academics. XRF analytical values are relative due to the use of the calibration curves calculated from measuring the reference standard materials such as Japanese Refractory Reference Materials (JRRM) series with certified values determined by wet chemical analysis. The development of the XRF analytical method from relative to absolute analysis will help much to determine the absolute values of samples from the fields where reference standard samples have not been prepared, and thus can be applied widely in many industries. The implement of the absolute XRF analysis for silica refractories requires high purity reagents and/or reference standard solution for the binary basic calibration curve, and theoretical matrix correction coefficients for the multi-components silica refractories analysis. The reproducibility and repeatability of this method for Al 2 O 3 5 mass% sample were 0.009 and 0.006 mass% in Al 2 O 3 and showed better values that those of ICP-AES recognized as an absolute method in JIS R 2212-2, which yielded 0.028 and 0.031 mass%, respectively. The XRF absolute analysis for JRRM 200 series, 201a and 205a does not show a bias but coincides with their certified values. (author)

  14. The fluorescence lifetime of BRI1-GFP as probe for the noninvasive determination of the membrane potential in living cells

    Elgass, K.; Caesar, K.; Schleifenbaum, F.; Meixner, A. J.; Harter, K.

    2010-02-01

    As the excited state lifetime of a fluorescent molecule depends on its environment, it is possible to use it as a probe for physico-chemical parameters of the surrounding medium. Whereas this is well known for many solid guest/host systems, only few reports of quantitative, temporal resolved in vivo studies to monitor the nano-environment for a protein-coupled chromophore such as GFP are known from literature. Here we present a novel approach to determine the membrane potential of living (plant) cells based on the fluorescence lifetime (FLT) analysis of membrane-located GFP. By using confocal sample scanning microscopy (CSSM) combined with fluorescence lifetime imaging microscopy, we recently showed that the phytohormone brassinolide (BL) induces cell wall expansion and a decrease in the FLT of the BRI1-GFP in living cells of Arabidopsis thaliana seedlings. BRI1 is the dominant functional receptor for BL in Arabidopsis and locates to the plasma membrane. Although the dependence of the FLT of GFP on its physico-chemical environment such as pH-value, refractive index and pressure has been reported, the observed FLT decrease of BRI1-GFP in response to BL application could not be explained by these parameters. However, our in vivo FLT and CSSM analyses indicate that the BLinduced change in the FLT of BRI1-GFP is caused by hyperpolarisation of the plasma membrane (Em). Thus, our results indicate that BRI1-GFP serves as sensitive and non-invasive probe for recording the Em of the plasma membrane in living plant cells with high spatio-temporal resolution.

  15. A guide for approval of x-ray fluorescence analysis devices

    1990-01-01

    This guide has been written to assist manufacturers, distributors and users of x-ray fluorescence analysis devices in the preparation of a submission to the Atomic Energy Control Board (AECB) in support of a request for approval of an x-ray fluorescence analysis device. Prior to the issuance of a Radioisotope licence authorizing the use or possession of an x-ray fluorescence analysis device in Canada, the design and construction of the device must be approved by the AECB. The AECB assessment is limited to the radiation safety aspects of use and packaging for transportation

  16. Acute toxicity of excess mercury on the photosynthetic performance of cyanobacterium, S. platensis--assessment by chlorophyll fluorescence analysis.

    Lu, C M; Chau, C W; Zhang, J H

    2000-07-01

    Measurement of chlorophyll fluorescence has been shown to be a rapid, non-invasive, and reliable method to assess photosynthetic performance in a changing environment. In this study, acute toxicity of excess Hg on the photosynthetic performance of the cyanobacterium S. platensis, was investigated by use of chlorophyll fluorescence analysis after cells were exposed to excess Hg (up to 20 microM) for 2 h. The results determined from the fast fluorescence kinetics showed that Hg induced a significant increase in the proportion of the Q(B)-non-reducing PSII reaction centers. The fluorescence parameters measured under the steady state of photosynthesis demonstrated that the increase of Hg concentration led to a decrease in the maximal efficiency of PSII photochemistry, the efficiency of excitation energy capture by the open PSII reaction centers, and the quantum yield of PSII electron transport. Mercury also resulted in a decrease in the coefficients of photochemical and non-photochemical quenching. Mercury may have an acute toxicity on cyanobacteria by inhibiting the quantum yield of photosynthesis sensitively and rapidly. Such changes occurred before any other visible damages that may be evaluated by other conventional measurements. Our results also demonstrated that chlorophyll fluorescence analysis can be used as a useful physiological tool to assess early stages of change in photosynthetic performance of algae in response to heavy metal pollution.

  17. Heavy metals analysis in fishes by the X-ray fluorescence method

    Perez Novara, Ana Ma.

    1986-04-01

    Among the sources of contamination in human beings we find ingestion of heavy metals. As it is common practice to pour industrial wastes in waters where fishes feed, some toxic elements present in water may pass to human beings through ingestion. It is therefore important to determine the concentrations of heavy metals present in fishes, mainly in those living in waters close to industrial zones or villages. Concentrations of heavy metals in tissue of fishes amount to ppm, hence making necessary the use of very sensitive analytical techniques which do not require a too complex preparation of the sample in order to avoid the loss or contamination of interesting elements of analysis while handling them, thus falsifying the results. The X-Ray Fluorescence method covers these requirements and is not destructive nor multi-elemental. The development of the technique of element analysis in fishes by X-Ray Fluorescence comprised several aspects. from sampling and storage to quantification, specially stressing the preparation of samples. The work was carried out with a Si-Li detector/monitor for solid state and associated electronic equipment. Cd-109 and Pu-238 sources were used to produce excitation, detection limits near 1 ppm were obtained in the majority of elements the technique attained for the analysis of this kind of samples fulfills the celerity, precision, accuracy, and sensitivity requirements. (author)

  18. Multi-elemental analysis of marine sediments of Sorsogon Bay using x-ray fluorescence spectroscopy

    Gonzales, Ralph Roly A.; Quirit, Leni L.; Rosales, Colleen Marciel F.; Pabroa, Preciosa Corazon B.; Sta Maria, Efren J.

    2011-01-01

    Metal composition and nutrient loadings of our bodies of water, when uncontrolled, may cause harmful bacterial contamination and pose threats in aquatic and human life. Toxic and trace element inputs in Sorsogon Bay sediments were determined using nuclear analytical techniques, more specifically, x-ray fluorescence spectrometry, in this study. Pre-treated marine sediment samples from Sorsogon Bay were homogenized using SPEX # 8000 mixer/mill and agate mortar and pestle, pelletized into 31-mm flat discs using SPEX 3630 X-Press and analyzed using PAN Analytical Epsilon 5 EDX X-ray Fluorescence Spectrometer with the emission and transmission method using silver and germanium secondary targets. Spectrum fitting performed using AXIL (Analysis of X-ray Spectra by Iterative Least-Squares Fitting), a subprogram in Quantitative X-ray Analysis System developed by the International Atomic Energy Agency and Quantitative Analysis of Environmental Samples program, was used for quantification of results. Results indicate generally moderate to high metal enrichment, specifically manganese, lead, cadmium, zinc and copper. Mercury and iron level enrichment are found to be low, marking an improvement from previous studies indicating high enrichment of these metals. (author)

  19. Energy dispersive x-ray fluorescence spectrometric determination of phosphorus, calcium, iron, zinc, and strontium in human bones

    Ohta, Akishige; Matsubayashi, Takashi; Itoman, Moritoshi

    1981-01-01

    Phosphorus, calcium, iron, zinc and strontium in a human bone extracted by surgery were determined by energy dispersive X-ray fluorescence spectrometry. The bone was decomposed with nitric acid, then diluted with water. A specific quantity of the solution was naturally dried on polyethylene film, and subjected to X-ray analysis. For determining the calibration curves in a mixture of phosphorus, calcium, iron, zinc and strontium, for the analysis of phosphorus and calcium, germanium was used as the secondary target and aluminum as the filter; and for the analysis of iron, zinc and strontium, molybdenum and molybdenum-aluminum were used, respectively. Consequently, the calibration curves were able to be obtained with high precision in the ranges from 5 to 500 μg of phosphorus, from 1 to 50 μg of calcium and from 0.1 to 1.0 μg of iron, zinc and strontium. In this way, in 1 mg of the human bone by wet weight, phosphorus, calcium, iron, zinc and strontium were able to be determined. (J.P.N.)

  20. Radionuclide X-ray fluorescence analysis of components of the environment

    Toelgyessy, J.; Havranek, E.; Dejmkova, E.

    1983-12-01

    The physical foundations and methodology are described of radionuclide X-ray fluorescence analysis. The sources are listed of air, water and soil pollution, and the transfer of impurities into biological materials is described. A detailed description is presented of the sampling of air, soil and biological materials and their preparation for analysis. Greatest attention is devoted to radionuclide X-ray fluorescence analysis of the components of the environment. (ES)

  1. Fluorescent carbon quantum dot hydrogels for direct determination of silver ions.

    Cayuela, A; Soriano, M L; Kennedy, S R; Steed, J W; Valcárcel, M

    2016-05-01

    The paper reports for the first time the direct determination of silver ion (Ag(+)) using luminescent Carbon Quantum Dot hydrogels (CQDGs). Carbon Quantum Dots (CQDs) with different superficial moieties (passivate-CQDs with carboxylic groups, thiol-CQDs and amine-CQDs) were used to prepare hybrid gels using a low molecular weight hydrogelator (LMWG). The use of the gels results in considerable fluorescence enhancement and also markedly influences selectivity. The most selective CQDG system for Ag(+) ion detection proved to be those containing carboxylic groups onto their surface. The selectivity towards Ag(+) ions is possibly due to its flexible coordination sphere compared with other metal ions. This fluorescent sensing platform is based on the strong Ag-O interaction which can quench the photoluminescence of passivate-CQDs (p-CQDs) through charge transfer. The limit of detection (LOD) and quantification (LOQ) of the proposed method were 0.55 and 1.83µgmL(-1), respectively, being applied in river water samples. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Surface area and volume determination of subgingival calculus using laser fluorescence.

    Shakibaie, Fardad; Walsh, Laurence J

    2014-03-01

    Visible red (655 nm) laser fluorescence (LF) devices are currently used for identifying deposits of subgingival calculus on the root surfaces of teeth during dental examination and treatment; however, it is not known how the fluorescence readings produced by commercially available LF systems correlate to the nature of the deposits. This laboratory study explored the correlation between LF digital readings and the surface area and volume of subgingival calculus deposits on teeth. A collection of 30 extracted human posterior teeth with various levels of subgingival deposits of calculus across 240 sites were used in a clinical simulation, with silicone impression material used to replicate periodontal soft tissues. The teeth were scored by two examiners by using three commercial LF systems (DIAGNOdent, DIAGNOdent Pen and KEY3). The silicone was removed, and the teeth were removed for photography at × 20 magnification under white or ultraviolet light. The surface area, thickness, and volume were calculated, and both linear least squares regression and nonlinear (Spearman's rank method) correlation coefficients were determined. Visible red LF digital readings showed better correlation to calculus volume than to surface area. Overall, the best performance was found for the KEY3 system (Spearman coefficient 0.59), compared to the Classic DIAGNOdent (0.56) and the DIAGNOdent Pen (0.49). These results indicate that while visible red LF systems vary somewhat in performance, their LF readings provide a useful estimation of the volume of subgingival calculus deposits present on teeth.

  3. Multipumping flow system for improving hydride generation atomic fluorescence spectrometric determinations

    Lopez-Garcia, Ignacio; Ruiz-Alcaraz, Irene; Hernandez-Cordoba, Manuel

    2006-01-01

    The advantages of using membrane micropumps rather than peristaltic pumps to introduce both sample and reagent solutions for hydride generation atomic fluorescence spectrometry are discussed. Arsenic was used as a test analyte to check the performance of the proposed manifold. Sample and reagent consumption was reduced 8-9 fold compared with continuous mode measurements made with peristaltic pumps, with no deterioration in sensitivity. The calibration graph was linear in the 0.05 to 2.5 μg l -1 As range using peak area as the analytical signal and maximum gain in the detector setting. A limit of detection (3σ) of 0.02 μg l -1 and relative standard deviation values close to 2% for 10 independent measurements of a 1 μg l -1 As solution were obtained. The sampling frequency increased from 45 to 102 h -1 with the subsequent saving in carrier gas used and reduction in wastes generated. The instrumental modification, which could be used for other elements currently determined by atomic fluorescence spectrometry, will permit hydride generators of more reduced dimensions to be constructed

  4. Quantitative fluorescence loss in photobleaching for analysis of protein transport and aggregation

    Wüstner Daniel

    2012-11-01

    Full Text Available Abstract Background Fluorescence loss in photobleaching (FLIP is a widely used imaging technique, which provides information about protein dynamics in various cellular regions. In FLIP, a small cellular region is repeatedly illuminated by an intense laser pulse, while images are taken with reduced laser power with a time lag between the bleaches. Despite its popularity, tools are lacking for quantitative analysis of FLIP experiments. Typically, the user defines regions of interest (ROIs for further analysis which is subjective and does not allow for comparing different cells and experimental settings. Results We present two complementary methods to detect and quantify protein transport and aggregation in living cells from FLIP image series. In the first approach, a stretched exponential (StrExp function is fitted to fluorescence loss (FL inside and outside the bleached region. We show by reaction–diffusion simulations, that the StrExp function can describe both, binding/barrier–limited and diffusion-limited FL kinetics. By pixel-wise regression of that function to FL kinetics of enhanced green fluorescent protein (eGFP, we determined in a user-unbiased manner from which cellular regions eGFP can be replenished in the bleached area. Spatial variation in the parameters calculated from the StrExp function allow for detecting diffusion barriers for eGFP in the nucleus and cytoplasm of living cells. Polyglutamine (polyQ disease proteins like mutant huntingtin (mtHtt can form large aggregates called inclusion bodies (IB’s. The second method combines single particle tracking with multi-compartment modelling of FL kinetics in moving IB’s to determine exchange rates of eGFP-tagged mtHtt protein (eGFP-mtHtt between aggregates and the cytoplasm. This method is self-calibrating since it relates the FL inside and outside the bleached regions. It makes it therefore possible to compare release kinetics of eGFP-mtHtt between different cells and

  5. Green analytical determination of emerging pollutants in environmental waters using excitation-emission photoinduced fluorescence data and multivariate calibration.

    Hurtado-Sánchez, María Del Carmen; Lozano, Valeria A; Rodríguez-Cáceres, María Isabel; Durán-Merás, Isabel; Escandar, Graciela M

    2015-03-01

    An eco-friendly strategy for the simultaneous quantification of three emerging pharmaceutical contaminants is presented. The proposed analytical method, which involves photochemically induced fluorescence matrix data combined with second-order chemometric analysis, was used for the determination of carbamazepine, ofloxacin and piroxicam in water samples of different complexity without the need of chromatographic separation. Excitation-emission photoinduced fluorescence matrices were obtained after UV irradiation, and processed with second-order algorithms. Only one of the tested algorithms was able to overcome the strong spectral overlapping among the studied pollutants and allowed their successful quantitation in very interferent media. The method sensitivity in superficial and underground water samples was enhanced by a simple solid-phase extraction with C18 membranes, which was successful for the extraction/preconcentration of the pollutants at trace levels. Detection limits in preconcentrated (1:125) real water samples ranged from 0.04 to 0.3 ng mL(-1). Relative prediction errors around 10% were achieved. The proposed strategy is significantly simpler and greener than liquid chromatography-mass spectrometry methods, without compromising the analytical quality of the results. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Nanoparticle-based, organic receptor coupled fluorescent chemosensors for the determination of phosphate

    Kaur, Navneet, E-mail: navneetkaur@pu.ac.in [Centre for Nanoscience and Nanotechnology (UIEAST), Panjab University, Chandigarh 160014 (India); Kaur, Simanpreet; Kaur, Amanpreet [Centre for Nanoscience and Nanotechnology (UIEAST), Panjab University, Chandigarh 160014 (India); Saluja, Preeti; Sharma, Hemant [Department of Chemistry, Indian Institute of Technology Ropar, Rupnagar, Punjab 140001 (India); Saini, Anu; Dhariwal, Nisha [Centre for Nanoscience and Nanotechnology (UIEAST), Panjab University, Chandigarh 160014 (India); Singh, Ajnesh; Singh, Narinder [Department of Chemistry, Indian Institute of Technology Ropar, Rupnagar, Punjab 140001 (India)

    2014-01-15

    The sensors have been developed using silver nanoparticles coated with organic ligands and are fully characterized with spectroscopic methods. The energy-dispersive X-ray (EDX) analysis revealed the presence of organic receptors on the surface of metal nanoparticles. These chemosensors were tested against a range of biological and environmentally relevant cations in the HEPES buffered DMSO/H{sub 2}O (8:2, v/v) solvent system. The fluorescence intensity of these chemosensors was quenched upon coordination with open shell metal ions such as Cu{sup 2+}/Fe{sup 3+}. Anion recognition properties of the corresponding metal complexes have been studied and the original fluorescence intensity of sensors was restored upon addition of phosphate (0–20 µM). Thus, a highly selective chemosensor has been devised for the micromolar estimation of phosphate in semi-aqueous medium. -- Highlights: • The silver nanoparticles have been decorated with organic receptors for chemosensor applications. • The sensor properties are developed for the estimation of phosphate anion. • Thus the sensor relies on the cation displacement assay. • The phosphate sensing event displays the “ON–OFF–ON” mode of switching in sensor.

  7. Determination of the carbohydrates from Notopterygium forbesii Boiss by HPLC with fluorescence detection.

    Zhang, Shijuan; Li, Chunli; Zhou, Guoying; Che, Guodong; You, Jinmao; Suo, Yourui

    2013-09-12

    A sensitive pre-column derivatization method was developed for analysis of carbohydrates by HPLC with fluorescence detection. The introduction of 2-(12-benzo[b]acridin-5(12H)-yl)-acetohydrazide (BAAH) with excellent fluorescence property into the molecules of monosaccharides greatly enhanced the HPLC sensitivity of the analytes. Meanwhile, derivatization with BAAH also greatly increased the hydrophobicity of the monosaccharides and made them elute at increased retention times. The monosaccharides with similar properties therefore could be completely separated due to the increased interaction between the analytes and the column. Component monosaccharides of the polysaccharides obtained from the roots, stems and leaves of Notopterygium forbesii Boiss (NF) were analyzed by the developed method. The results indicated that the polysaccharides of NF were mainly composed of d-galactose and d-glucose. This is the first systematic study of the sugar composition of the polysaccharides of NF. It will be helpful for the quality control of NF. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Determination of 2-alkylcyclobutanones by combining precolumn derivatization with 1-naphthalenyl hydrazine and ultra-performance liquid chromatography with fluorescence detection.

    Meng, Xiangpeng; Tong, Tong; Wang, Lianrong; Liu, Hanxia; Chan, Wan

    2016-05-01

    2-Alkylcyclobutanones (2-ACBs) are uniquely formed when triglycerides-containing food products are exposed to ionizing radiation. Thus, 2-ACBs have been used as marker molecules to identify irradiated food. Most methods to determine 2-ACBs involve mass spectrometric detection after chromatographic separation. The spectrofluorometer is rarely used to determine 2-ACBs because these molecules do not fluoresce. In this study, we developed an ultra-performance liquid chromatography (UPLC) method to determine 2-ACBs. 2-ACBs were converted into fluorophores after reacting with 1-naphthalenyl hydrazine to facilitate their sensitive and selective detection using a fluorescence detector (FLD). Analysis of 2-ACBs using our developed UPLC-FLD method allows sensitive determination of 2-ACBs at a detection limit of 2 ng 2-ACBs per g of fat (30 pg/injection), which is significantly lower than that of existing analytical methods. After validation for trueness and precision, the method was applied to γ-irradiated chicken samples to determine their 2-ACB content. Comparative studies employing liquid chromatography-tandem mass spectrometric method revealed no systematic difference between the two methods, thereby demonstrating that the proposed UPLC-FLD method can be suitably used to determine 2-ACBs in irradiated foodstuffs. Graphical Abstract Determination of radiation-induced food-borne 2-dodecylcyclobutanone and 2-tetradecylcyclobutanone by combining 1-naphthalenyl hydrazine derivatization and ultra-performance liquid chromatography with fluorescence detection.

  9. Determination of 40K radioactivity in the soil using energy dispersive X ray fluorescence spectrometer

    Lu Weiwei; Song Fuxiang; Zeng Liping; Lu Hongning

    2012-01-01

    The 40 K radioactive of' the pressed powder sample was determined by Epsilon 5 high-energy polarized energy dispersive X ray fluorescence (EDXRF) spectrometer. The correlation coefficient of the standard curve method was 0.9910, the precision was 2.98% and the relative deviation of the measurement standard samples was up to 6.40%, which showed that the precision and accuracy of the method were also good. Simultaneous measurement of seven soil samples using this method and γ-spectrometer were carried, the results of two analytical methods were compared using a paired t-test by SPSS program, which showed that there was no significant difference in the two sets of data, P>0.05. It indicated that EDXRF could be a potential simple method for analyzing 40 K radioactive in soil samples. (authors)

  10. Impurities determination in uranium eluates by total reflection X-ray fluorescence

    Vazquez, Cristina; Bellavigna, Horacio J.; Eppis, Maria R.; Ramella, Jose L.

    1999-01-01

    The chemical control of impurities in nuclear materials is indispensable in order to assure an efficient operation of the reactors. The maximum concentration admitted depends of the elements and in most cases are in the parts per billion range. Conventional analytical methods require a pre-concentration treatment of the sample and a previous separation of the matrix (uranium). This paper investigates the use of the total reflection X-ray fluorescence as an alternative methodology for the determination of impurities in nuclear materials, namely K, Ca, Ti, Cr, Mn, Fe, Ni, Cu and As. The detection limits obtained were in the range of 0.1 to 20 ng/ml for a 1000 seconds counting time. (author)

  11. Application of X-ray fluorescence (WDXRF): thickness and chemical composition determination of thin films

    Scapin, Valdirene de Oliveira.

    2004-01-01

    In this work a procedure is described for thickness and quantitative chemical composition of thin films by wavelength dispersion X-ray fluorescence (WDXRF) using Fundamental Parameters method. This method was validated according to quality assurance standard and applied sample Al, Cr, TiO2, Ni, ZrO2 (single thickness) and Ni/Cr (double thickness) on glass; Ni on steel and metallic zinc and TiO2 on metallic iron (single thickness), all the sample were prepared for physical deposition of vapor (PVD). The thickness had been compared with Absorption (FRX-A) and Rutherford Backscattering Spectrometry (RBS) methods; the result showed good efficiency of the fundamental parameters method. Sample structural characteristics analyzed by X ray diffraction (XRD) showed any influence in the thickness determinations. (author)

  12. X-Ray Fluorescence to Determine Zn in Bolivian Children using Hair Samples

    Tellería Narvaez, C.A.; Fernández Alcázar, S.; Barrientos Zamora, F.G.; Chungara Castro, J.; Luna Lauracia, I.; Mamani Tola, H.; Mita Peralta, E.; Muñoz Gosálvez, A.O.; Romero Bolaños, L.E.; Ramírez Ávila, G.M.

    2014-01-01

    As a first step in the evaluation of nutritional levels in Bolivian children (8–13 years-old), we carried out X-Ray Fluorescence measurements in hair samples of children belonging to different social classes and living either in rural areas or in cities. The aim of this study is to contribute to health policies tending to improve the global health of children and consequently avoid malnutrition. Our method intends to have maximum reliability and at the same time be as simple as possible from an experimental point of view. Additionally, we use this method to determine some other elements such as Fe, Cu, Pb, As and Hg, the latter three considered as contaminants that could be present in children living in areas which neighbor mines and industries. This work will be complemented by some biological and medical tests

  13. Thin coating thickness determination using radioisotope-excited x-ray fluorescence spectrometry

    Del Castillo, Lorena A.; Calix, Virginia S.

    2001-01-01

    Three different approaches on thin coating thickness determination using a radioisotope-excited x-ray fluorescence spectrometry were demonstrated and results were compared. A standard of thin layer of gold (Au) on a nickel (Ni) substrate from the US National Bureau of Standards (with a nominal thickness of 0.300505 microns of at least 99.9% Au electrodeposited over 2 nils of Ni) on low carbon steel (1010) was analyzed using a Cd 109-excited XRF system. Au thickness computations were done using the (a) thin standard approach, (b) thick standard approach, and (c) x-ray absorption method (ASTM A754-79 1982). These three methods yielded results within the limit set by the American Society for Testing Materials (ASTM), which is +/-3%. Of the three methods, the thick standard yielded the best result with 0.124% error. (Author)

  14. X-Ray Fluorescence to Determine Zn in Bolivian Children using Hair Samples

    Tellería Narvaez, C.A.; Fernández Alcázar, S.; Barrientos Zamora, F.G.; Chungara Castro, J.; Luna Lauracia, I.; Mamani Tola, H.; Mita Peralta, E.; Muñoz Gosálvez, A.O. [Centro de Investigaciones y Aplicaciones Nucleares (CIAN-Viacha), Viacha (Bolivia, Plurinational State of); Romero Bolaños, L.E. [Instituto Boliviano de Ciencia y Tecnología Nuclear Av. 6 de Agosto 2905, La Paz (Bolivia, Plurinational State of); Ramírez Ávila, G.M., E-mail: gramirez@ulb.ac.be [Instituto de Investigaciones Físicas, Universidad Mayor de San Andrés, Campus Universitario Cota Cota, Casilla 8635, La Paz (Bolivia, Plurinational State of)

    2014-06-15

    As a first step in the evaluation of nutritional levels in Bolivian children (8–13 years-old), we carried out X-Ray Fluorescence measurements in hair samples of children belonging to different social classes and living either in rural areas or in cities. The aim of this study is to contribute to health policies tending to improve the global health of children and consequently avoid malnutrition. Our method intends to have maximum reliability and at the same time be as simple as possible from an experimental point of view. Additionally, we use this method to determine some other elements such as Fe, Cu, Pb, As and Hg, the latter three considered as contaminants that could be present in children living in areas which neighbor mines and industries. This work will be complemented by some biological and medical tests.

  15. Determination of impurities in magnesium and aluminium by X-ray fluorescence spectrometry

    Roca, M.; Diaz-Guerra, J.P.

    1979-01-01

    The determination of traces of Al, Cr, Cu, Fe, Mn, Ni, Pb, Si and of Bi, Cr, Cu, Fe, Ga, Mg, Mn, Ni, Pb, Si, Sn, Ti, V and Zn in samples of magnesium and aluminium, respectively, by means of X-ray fluorescence spectrometry, are studied. An automatic sequential spectrometer with an on-line computer for the treatment of data has been employed. The most suitable measurement parameters have been chosen for each element in order to achieve detection limits to a few p.p.m. For magnesium in the form of drillings the analyses are performed with satisfactory results for most impurities by pressing the samples into briquettes and employing metallic discs as standards. Correction methods for the spectral interferences of Ti on V, and V on Cr have been applied. (author)

  16. Determination of trace metals in nuclear-grade uranium dioxide by X-ray fluorescence spectrometry

    Salvador, V.L.R.; Imakuma, K.

    1988-04-01

    A method is described for the simultaneous determination of low concentrations of Ca, Cr, Cu, Fe, Mn and Ni in nuclear-grade uranium dioxide by X-ray fluorescence spectrometry, without the use of chemical treatment. The lower limits of detection range from 2 μg g -1 for nickel and manganese to 5 μg g -1 for copper. Samples are prepared in the form of double-layer pellets with boric acid as a binding agent. Standards are prepared in a U 3 O 8 matrix, which is more chemically stable than UO 2 and has similar matrix behaviour. The correlation coefficients for calibration curves are better than 0.999. Erros range from 2.4 % for chromium to 6.8 % for nickel. (author) [pt

  17. Determination of Te in soldering tin using continuous flowing electrochemical hydride generation atomic fluorescence spectrometry

    Jiang Xianjuan; Gan Wuer; Han Suping; He Youzhao

    2008-01-01

    An electrochemical hydride generation system was developed for the detection of Te by coupling an electrochemical hydride generator with atomic fluorescence spectrometry. Since TeH 2 is unstable and easily decomposes in solution, a reticular W filament cathode was used in the present system. The TeH 2 generated on the cathode surface was effectively driven out by sweeping gas from the cathode chamber. In addition, a low temperature electrochemical cell (10 deg. C) was applied to reduce the decomposition of TeH 2 in solution. The limit of detection (LOD) was 2.2 ng ml -1 and the relative standard deviation (RSD) was 3.9% for nine consecutive measurements of standard solution. This method was successfully employed for determination of Te in soldering tin material

  18. LASER FLUORESCENCE EEM PROBE FOR CONE PENETROMETER POLLUTION ANALYSIS

    A fiber optic LIF (Laser induced fluorescence) EEM (Excitation emission matrix) instrument for CPT deployment has been successfully developed and field tested. The system employs a Nd: YAG laser and Raman shifter as a rugged field portable excitation source. This excitation sou...

  19. Time-resolved fluorescence analysis of the mobile flavin cofactor

    Conformational heterogeneity of the FAD cofactor in -hydroxybenzoate hydroxylase (PHBH) was investigated with time-resolved polarized flavin fluorescence. For binary enzyme/substrate (analogue) complexes of wild-type PHBH and Tyr222 mutants, crystallographic studies have revealed two distinct flavin conformations ...

  20. Automated image analysis for quantitative fluorescence in situ hybridization with environmental samples.

    Zhou, Zhi; Pons, Marie Noëlle; Raskin, Lutgarde; Zilles, Julie L

    2007-05-01

    When fluorescence in situ hybridization (FISH) analyses are performed with complex environmental samples, difficulties related to the presence of microbial cell aggregates and nonuniform background fluorescence are often encountered. The objective of this study was to develop a robust and automated quantitative FISH method for complex environmental samples, such as manure and soil. The method and duration of sample dispersion were optimized to reduce the interference of cell aggregates. An automated image analysis program that detects cells from 4',6'-diamidino-2-phenylindole (DAPI) micrographs and extracts the maximum and mean fluorescence intensities for each cell from corresponding FISH images was developed with the software Visilog. Intensity thresholds were not consistent even for duplicate analyses, so alternative ways of classifying signals were investigated. In the resulting method, the intensity data were divided into clusters using fuzzy c-means clustering, and the resulting clusters were classified as target (positive) or nontarget (negative). A manual quality control confirmed this classification. With this method, 50.4, 72.1, and 64.9% of the cells in two swine manure samples and one soil sample, respectively, were positive as determined with a 16S rRNA-targeted bacterial probe (S-D-Bact-0338-a-A-18). Manual counting resulted in corresponding values of 52.3, 70.6, and 61.5%, respectively. In two swine manure samples and one soil sample 21.6, 12.3, and 2.5% of the cells were positive with an archaeal probe (S-D-Arch-0915-a-A-20), respectively. Manual counting resulted in corresponding values of 22.4, 14.0, and 2.9%, respectively. This automated method should facilitate quantitative analysis of FISH images for a variety of complex environmental samples.

  1. Determination of emamectin residues in the tissues of Atlantic salmon (Salmo salar L.) using HPLC with fluorescence detection.

    Kim-Kang, H; Crouch, L S; Bova, A; Robinson, R A; Wu, J

    2001-11-01

    An accurate, reliable, and reproducible assay for the determination of residual concentrations of emamectin B(1a) in muscle, skin, and intact muscle/skin in natural proportions from Atlantic salmon treated with SCH 58854 (emamectin benzoate) is described. The determinative method was developed and validated using fortified control tissues at five levels over a range of 50-800 ng/g as well as tissues containing incurred levels in the same range. Incurred tissues were obtained from a metabolism study of [(3)H]emamectin benzoate in Atlantic salmon. The assay employs processing of a tissue ethyl acetate extract on a propylsulfonic acid solid phase extraction cartridge, followed by derivatization with trifluoroacetic anhydride in the presence of N-methylimidazole. Following separation using reversed phase HPLC, the amount of derivatized emamectin B(1a) is determined by fluorescence detection. The theoretical limits of detection were determined from the analysis of control tissue matrices to be 2.6, 3.3, and 3.8 ng/g as emamectin B(1a) for muscle, skin, and intact muscle/skin, respectively. Likewise, the theoretical limits of quantitation (LOQ) were determined to be 6.9, 8.1, and 9.5 ng/g as emamectin B(1a) for muscle, skin, and intact muscle/skin, respectively. The lowest fortification level used for method validation was 50 ng/g, which served as the effective LOQ for the method. The overall percent recoveries (+/-% CV) were 94.4 +/- 6.89% (n = 25) for muscle, 88.4 +/- 5.35% (n = 25) for skin, and 88.0 +/- 3.73% for intact muscle/skin (n = 25). Accuracy, precision, linearity, selectivity, and ruggedness were demonstrated. The structure of the final fluorescent derivative of emamectin B(1a) free base was identified by ESI(+)/LC-MS. The frozen storage stability of [(3)H]emamectin B(1a) in tissues with incurred residues was demonstrated for approximately 15 months by radiometric analysis and for an additional approximately 13 months by fluorometric analysis for a total of

  2. X-Ray Diffraction and Fluorescence Instrument for Mineralogical Analysis at the Lunar Surface, Phase II

    National Aeronautics and Space Administration — We propose to develop LUNA, a compact and lightweight X-Ray Diffraction (XRD) / X-Ray Fluorescence (XRF) instrument for mineralogical analysis of regolith, rock...

  3. X-Ray Diffraction and Fluorescence Instrument for Mineralogical Analysis at the Lunar Surface, Phase I

    National Aeronautics and Space Administration — We propose to develop a compact and lightweight X-Ray Diffraction (XRD) / X-Ray Fluorescence (XRF) instrument for analysis of mineralogical composition of regolith,...

  4. Sampling, storage and sample preparation procedures for X ray fluorescence analysis of environmental materials

    1997-06-01

    X ray fluorescence (XRF) method is one of the most commonly used nuclear analytical technique because of its multielement and non-destructive character, speed, economy and ease of operation. From the point of view of quality assurance practices, sampling and sample preparation procedures are the most crucial steps in all analytical techniques, (including X ray fluorescence) applied for the analysis of heterogeneous materials. This technical document covers recent modes of the X ray fluorescence method and recent developments in sample preparation techniques for the analysis of environmental materials. Refs, figs, tabs

  5. [Rapid determination of major and trace elements in the salt lake clay minerals by X-ray fluorescence spectrometry].

    Wang, Xiao-Huan; Meng, Qing-Fen; Dong, Ya-Ping; Chen, Mei-Da; Li, Wu

    2010-03-01

    A rapid multi-element analysis method for clay mineral samples was described. This method utilized a polarized wave-length dispersive X-ray fluorescence spectrometer--Axios PW4400, which had a maximum tube power of 4 000 watts. The method was developed for the determination of As, Mn, Co, Cu, Cr, Dy, Ga, Mo, P, Pb, Rb, S, Sr, Ni, ,Cs, Ta, Th, Ti, U, V, Y, Zn, Zr, MgO, K2O, Na2O, CaO, Fe2O3, Al2O3, SiO2 and so on. Thirty elements in clay mineral species were measured by X-ray fluorescence spectrometry with pressed powder pellets. Spectral interferences, in particular the indirect interferences of each element, were studied. A method to distinguish the interference between each other periodic elements in element periodic table was put forward. The measuring conditions and existence were mainly investigated, and the selected background position as well as corrected spectral overlap for the trace elements were also discussed. It was found that the indirect spectral overlap line was the same important as direct spectral overlap line. Due to inducing the effect of indirect spectral overlap, some elements jlike Bi, Sn, W which do not need analysis were also added to the elements channel. The relative standard deviation (RSD) was in the range of 0.01% to 5.45% except three elements Mo, Cs and Ta. The detection limits, precisions and accuracies for most elements using this method can meet the requirements of sample analysis in clay mineral species.

  6. Determination of lead in clay enameled by X-ray fluorescence technique in Total reflection and by Scanning Electron Microscopy

    Zarazua O, G.; Carapia M, L.

    2000-01-01

    This work has the objective of determining lead free in the glazed commercial stewing pans using the X-ray fluorescence technique in Total reflection (FRX) and the observation and semiquantitative determination of lead by Analytical Scanning Electron Microscopy (ASEM). (Author)

  7. Method 445.0 In Vitro Determination of Chlorophyll a and Pheophytin ain Marine and Freshwater Algae by Fluorescence

    This method provides a procedure for low level determination of chlorophyll a (chl a) and its magnesium free derivative, pheophytin a (pheo a), in marine and freshwater phytoplankton using fluorescence detection.(1,2) Phaeophorbides present in the sample are determined collective...

  8. Determination of non-ionic surfactants in technologic liquors and effluents by X-ray fluorescent spectrometry

    Dankowski, P.; Majda, J.

    1977-01-01

    The method has been worked out for determination of non-ionic surfactants in technological liquors and effluents, based on the X-ray fluorescent spectrometry with an initial concentration by means of the phosphomolybdic acid. The method is suitable for a quantitative determination of ethylene oxide adducts in a wide range of applicable concentrations, the trace-ones included. (M.Z.)

  9. [Determination of urea in canned foods by high performance liquid chromatography-fluorescence detection coupled with precolumn derivatization].

    Zeng, Qi; Zhang, Jin; Xu, Dunming; Zhang, Zhigang; Ke, Zhicheng

    2015-01-01

    A method for the determination of urea residue in canned foods by high performance liquid chromatography-fluorescence detection (HPLC-FLD) coupled with precolumn derivatization was established. The sample (5.0 g), including canned edible fungi, fruit, vegetable, fish, and meat was extracted with 20 mL 1% (v/v) acetic acid solution. The extract was centrifuged, filtrated, and then derivatized with xanthydrol. The analysis was completed with HPLC-FLD. A good linear relationship was obtained in the range of 0.1-500 mg/L with the correlation coefficients more than 0.9995. The average recoveries of urea spiked at 0.001-30 g/kg levels in five kinds of canned foods ranged from 80.2% to 109.7% with the RSDs of 2.05%-6.53%. The limit of detection (LOD) was 0.5 mg/kg, and the limit of quantitation (LOQ) was 1.0 mg/kg. The proposed procedure was then applied to the analysis of 168 real samples collected from Xiamen, Fujian Province, China. The existence of urea was found in three pork cans with contents of 10.6, 62.1 and 2.6 mg/kg, respectively. The method is stable, reliable, simple and suitable for the determination of urea in canned foods, and has great potential for routine analysis in foodstuffs.

  10. X-ray fluorescence determination of Sn, Sb, Pb in lead-based bearing alloys using a solution technique

    Tian, Lunfu; Wang, Lili; Gao, Wei; Weng, Xiaodong; Liu, Jianhui; Zou, Deshuang; Dai, Yichun; Huang, Shuke

    2018-03-01

    For the quantitative analysis of the principal elements in lead-antimony-tin alloys, directly X-ray fluorescence (XRF) method using solid metal disks introduces considerable errors due to the microstructure inhomogeneity. To solve this problem, an aqueous solution XRF method is proposed for determining major amounts of Sb, Sn, Pb in lead-based bearing alloys. The alloy samples were dissolved by a mixture of nitric acid and tartaric acid to eliminated the effects of microstructure of these alloys on the XRF analysis. Rh Compton scattering was used as internal standard for Sb and Sn, and Bi was added as internal standard for Pb, to correct for matrix effects, instrumental and operational variations. High-purity lead, antimony and tin were used to prepare synthetic standards. Using these standards, calibration curves were constructed for the three elements after optimizing the spectrometer parameters. The method has been successfully applied to the analysis of lead-based bearing alloys and is more rapid than classical titration methods normally used. The determination results are consistent with certified values or those obtained by titrations.

  11. Simultaneous determination of Hg, Pb, As, Cu, Zn and Ni in natural waters (with humic material) by energy dispersive X-ray fluorescence

    Morales S, E.A.; Zepeda L, E.

    1988-05-01

    Standardization of a method for simultaneous quantification of Hg, Pb, As, Cu, Zn and Ni in natural waters with humic acid contents was carried out. APDC for complexing free ions and silica gel as adsorber of metallic humates and further filtration were employed. X-ray fluorescence analysis was performed on filters. Good results were found for silica-gel as adsorber. Detection limits of 4 nanograms/milliliter were determined. (author)

  12. Elemental analysis of granite by instrumental neutron activation analysis (INAA) and X-ray fluorescence analysis (XRF)

    El-Taher, A.

    2012-01-01

    The instrumental neutron activation analysis technique (INAA) was used for qualitative and quantitative analysis of granite samples collected from four locations in the Aswan area in South Egypt. The samples were prepared together with their standards and simultaneously irradiated in a neutron flux of 7×10 11 n/cm 2 s in the TRIGA Mainz research reactor. Gamma-ray spectra from an hyper-pure germanium detector were analyzed. The present study provides the basic data of elemental concentrations of granite rocks. The following elements have been determined Na, Mg, K, Fe, Mn, Sc, Cr, Ti, Co, Zn, Ga, Rb, Zr, Nb, Sn, Ba, Cs, La, Ce, Nd, Sm, Eu, Yb, Lu, Hf, Ta, Th and U. The X-ray fluorescence (XRF) was used for comparison and to detect elements, which can be detected only by XRF such as F, S, Cl, Co, Cu, Mo, Ni, Pb, Se and V. The data presented here are our contribution to understanding the elemental composition of the granite rocks. Because there are no existing databases for the elemental analysis of granite, our results are a start to establishing a database for the Egyptian granite. It is hoped that the data presented here will be useful to those dealing with geochemistry, granite chemistry and related fields. - Highlights: ► Instrumental neutron activation analysis technique (INAA) was used for qualitative and quantitative analysis of granite. ► The samples were prepared together with their standards and simultaneously irradiated in a neutron flux of 7×10 11 n/cm 2 s in the TRIGA Mainz research reactor. ► Following elements have been determined Na, Mg, K, Fe, Mn, Sc, Cr, Ti, Co, Zn, Ga, Rb, Zr, Nb, Sn, Ba, Cs, La, Ce, Nd, Sm, Eu, Yb, Lu, Hf, Ta, Th and U.

  13. The MicroAnalysis Toolkit: X-ray Fluorescence Image Processing Software

    Webb, S. M.

    2011-01-01

    The MicroAnalysis Toolkit is an analysis suite designed for the processing of x-ray fluorescence microprobe data. The program contains a wide variety of analysis tools, including image maps, correlation plots, simple image math, image filtering, multiple energy image fitting, semi-quantitative elemental analysis, x-ray fluorescence spectrum analysis, principle component analysis, and tomographic reconstructions. To be as widely useful as possible, data formats from many synchrotron sources can be read by the program with more formats available by request. An overview of the most common features will be presented.

  14. Quantification of epithelial cells in coculture with fibroblasts by fluorescence image analysis.

    Krtolica, Ana; Ortiz de Solorzano, Carlos; Lockett, Stephen; Campisi, Judith

    2002-10-01

    To demonstrate that senescent fibroblasts stimulate the proliferation and neoplastic transformation of premalignant epithelial cells (Krtolica et al.: Proc Natl Acad Sci USA 98:12072-12077, 2001), we developed methods to quantify the proliferation of epithelial cells cocultured with fibroblasts. We stained epithelial-fibroblast cocultures with the fluorescent DNA-intercalating dye 4,6-diamidino-2-phenylindole (DAPI), or expressed green fluorescent protein (GFP) in the epithelial cells, and then cultured them with fibroblasts. The cocultures were photographed under an inverted microscope with appropriate filters, and the fluorescent images were captured with a digital camera. We modified an image analysis program to selectively recognize the smaller, more intensely fluorescent epithelial cell nuclei in DAPI-stained cultures and used the program to quantify areas with DAPI fluorescence generated by epithelial nuclei or GFP fluorescence generated by epithelial cells in each field. Analysis of the image areas with DAPI and GFP fluorescences produced nearly identical quantification of epithelial cells in coculture with fibroblasts. We confirmed these results by manual counting. In addition, GFP labeling permitted kinetic studies of the same coculture over multiple time points. The image analysis-based quantification method we describe here is an easy and reliable way to monitor cells in coculture and should be useful for a variety of cell biological studies. Copyright 2002 Wiley-Liss, Inc.

  15. Pathological diagnosis of bladder cancer by image analysis of hypericin induced fluorescence cystoscopic images

    Kah, James C. Y.; Olivo, Malini C.; Lau, Weber K. O.; Sheppard, Colin J. R.

    2005-08-01

    Photodynamic diagnosis of bladder carcinoma based on hypericin fluorescence cystoscopy has shown to have a higher degree of sensitivity for the detection of flat bladder carcinoma compared to white light cystoscopy. The potential of the photosensitizer hypericin-induced fluorescence in performing non-invasive optical biopsy to grade bladder cancer in vivo using fluorescence cystoscopic image analysis without surgical resection for tissue biopsy is investigated in this study. The correlation between tissue fluorescence and histopathology of diseased tissue was explored and a diagnostic algorithm based on fluorescence image analysis was developed to classify the bladder cancer without surgical resection for tissue biopsy. Preliminary results suggest a correlation between tissue fluorescence and bladder cancer grade. By combining both the red-to-blue and red-to-green intensity ratios into a 2D scatter plot yields an average sensitivity and specificity of around 70% and 85% respectively for pathological cancer grading of the three different grades of bladder cancer. Therefore, the diagnostic algorithm based on colorimetric intensity ratio analysis of hypericin fluorescence cystoscopic images developed in this preliminary study shows promising potential to optically diagnose and grade bladder cancer in vivo.

  16. Determination of multi-element profiles of soil using energy dispersive X-ray fluorescence (EDXRF)

    Yu, K.N.; Yeung, Z.L.L.; Lee, L.Y.L.; Stokes, M.J.; Kwok, R.C.W.

    2002-01-01

    The source profile for soil in Hong Kong is important both for determination of the main air pollutant source in Hong Kong and for assessment of the impact of Asian dust storms on Hong Kong. Soil associated with different rock types have been sampled, and the concentrations of 19 chemical elements, Na, Al, Si, Ti, V, Cr, Mn, Fe, Co, K, Ca, Ni, Cu, Zn, Pb, Rb, Sr, Y and Zr, have been determined using energy dispersive X-ray fluorescence. A profile for the average soil for Hong Kong has been determined by taking average values for the different soil categories. The values for the Hong Kong soil are commensurate with values for rural soil derived by other workers, except that Hong Kong soil has much lower Fe and Ca concentrations. The abundance of Al, Ca and Fe in the average Hong Kong soil are 9.23%, 0.11% and 0.85%. We conclude that Ca provides a good marker element for identifying dust episodes in Hong Kong while Al does not

  17. Total reflection X-ray Fluorescence determination of interfering elements rubidium and uranium by profile fitting

    Dhara, Sangita; Khooha, Ajay; Singh, Ajit Kumar; Tiwari, M. K.; Misra, N. L.

    2018-06-01

    Systematic studies to assess the analytical parameters obtained in the total reflection X-ray fluorescence (TXRF) determinations of interfering elements Rb and U using profile fitting are reported in the present manuscript. The X-ray lines Rb Kα and U Lα having serious spectral interference (ΔE = 218 eV), have been used as analytical lines. The intensities of these X-ray lines have been assessed using profile fitting. In order to compare the analytical results of Rb determinations in presence of U, with and without U excitation, synchrotron radiation was tuned to energy just above and below the U Labs edge. This approach shall excite both Rb Kα and U Lα simultaneously and Rb Kα selectively. Finally, the samples were also analyzed with a laboratory based TXRF spectrometer. The analytical results obtained in all these conditions were comparable. The authenticity of the results was assessed by analyzing U with respect to Rb in Rb2U(SO4)3, a standard reference material for U. The average precision obtained for TXRF determinations was below 3% (RSD, n = 3, 1σ) and the percent deviation of TXRF values from the expected values calculated on the basis of sample preparation was within 3%.

  18. Determination of carbon in natural freshwater biofilms with total reflection X-ray fluorescence spectrometry

    Ovari, M.; Streli, C.; Wobrauschek, P.; Zaray, Gy.

    2009-01-01

    There is a growing interest in determination of low Z elements, i.e., carbon to phosphorus, in biological samples. Total reflection X-ray fluorescence spectrometry (TXRF) has been already established as suitable trace element analytical method with low sample demand and quite good quantification limits. Recently, the determinable element range was extended towards Z = 6 (carbon). Biofilms can be used for biomonioring purposes in the aquatic environment. Besides the trace metals, especially the determination of the carbon content is important for the better understanding of the early stage of biofilm formation. For this, an ATI low Z spectrometer equipped with Cr-anode X-ray tube, multilayer monochromator, vacuum chamber, and a Si(Li) detector with ultra thin window was used. Biofilms were grown on two different artificial supports (granite and plexiglass), freeze dried, suspended in high purity water and analyzed. As an internal standard the natural titanium content of the biofilms was used. The accuracy of the method was checked by total carbon measurement using a combusting carbon analyzer.

  19. Determination of carbon in natural freshwater biofilms with total reflection X-ray fluorescence spectrometry

    Ovari, M. [Department of Analytical Chemistry, Eoetvoes University, Budapest, H-1117, Budapest, Pazmany Peter stny. 1/a. (Hungary)], E-mail: ovari@chem.elte.hu; Streli, C.; Wobrauschek, P. [Atominstitut of the Austrian Universities, TU-Wien, Stadionallee 2, A-1020, Wien (Austria); Zaray, Gy. [Department of Analytical Chemistry, Eoetvoes University, Budapest, H-1117, Budapest, Pazmany Peter stny. 1/a. (Hungary); Cooperative Research Centre of Environmental Chemistry, Eoetvoes University, Budapest, H-1117, Budapest, Pazmany Peter stny. 1/a. (Hungary)

    2009-08-15

    There is a growing interest in determination of low Z elements, i.e., carbon to phosphorus, in biological samples. Total reflection X-ray fluorescence spectrometry (TXRF) has been already established as suitable trace element analytical method with low sample demand and quite good quantification limits. Recently, the determinable element range was extended towards Z = 6 (carbon). Biofilms can be used for biomonioring purposes in the aquatic environment. Besides the trace metals, especially the determination of the carbon content is important for the better understanding of the early stage of biofilm formation. For this, an ATI low Z spectrometer equipped with Cr-anode X-ray tube, multilayer monochromator, vacuum chamber, and a Si(Li) detector with ultra thin window was used. Biofilms were grown on two different artificial supports (granite and plexiglass), freeze dried, suspended in high purity water and analyzed. As an internal standard the natural titanium content of the biofilms was used. The accuracy of the method was checked by total carbon measurement using a combusting carbon analyzer.

  20. Fluorescent Probes for Analysis and Imaging of Monoamine Oxidase Activity

    Kim, Dokyoung; Jun, Yong Woong; Ahn, Kyo Han [POSTECH, Pohang (Korea, Republic of)

    2014-05-15

    Monoamine oxidases catalyze the oxidative deamination of dietary amines and amine neurotransmitters, and assist in maintaining the homeostasis of the amine neurotransmitters in the brain. Dysfunctions of these enzymes can cause neurological and behavioral disorders including Parkinson's and Alzheimer's diseases. To understand their physiological roles, efficient assay methods for monoamine oxidases are essential. Reviewed in this Perspective are the recent progress in the development of fluorescent probes for monoamine oxidases and their applications to enzyme assays in cells and tissues. It is evident that still there is strong need for a fluorescent probe with desirable substrate selectivity and photophysical properties to challenge the much unsolved issues associated with the enzymes and the diseases.

  1. In situ Analysis of Coral Recruits Using Fluorescence Imaging

    Adi Zweifler

    2017-09-01

    Full Text Available Recruitment is a fundamental process that influences coral population dynamics as well as reef community structure. To date, coral recruitment success rates are poorly quantified because survey methods are labor-intensive and require manual interpretation. Thus, they are prone to human errors and have low repeatability—a gap we aim to bridge in this research. Since both corals and their symbiotic algae contain fluorescent pigments (chlorophyll and fluorescent proteins, we used the non-invasive Fluorescence Imaging System (FluorIS and developed a methodology to acquire daytime fluorescent photographs and identify coral recruits in them. We tested our method by monitoring 20 random quadrats at two sites in the Gulf of Aqaba, Israel. The quadrats were surveyed once a month for 8 months in order to track the settlement, mortality and survival rates of new coral recruits. We demonstrate daytime imaging using our method and identification of coral recruits as small as 1 mm in diameter, in a 20 × 20 cm quadrat. Our results show that this photographic method reduces surveyor errors and improves precision. The surveys revealed that on average, there are ~2 new coral recruit settlements (<2 cm for a quadrat (40 cm2 per month and that 83% of them survive the first month. Our study suggests a relative stability in the Gulf of Aqaba coral population during the survey period. The ability to survey recruits during the day using low-cost, easy-to-use photographic equipment has the potential to contribute significantly to the standardization of coral reef monitoring and management tools, at a time when the world's coral reefs are declining due to local and global stressors.

  2. Technique of sample preparation for analysis of gasoline and lubricating oils by X-ray fluorescence analysis

    Avila P, P.

    1990-03-01

    The X-ray fluorescence laboratory of the National Institute of Nuclear Research when not having a technique for the analysis of oils it has intended, with this work, to develop a preparation technique for the analysis of the metals of Pb, Cr, Ni, V and Mo in gasolines and oils, by means of the spectrometry by X-ray fluorescence analysis. The obtained results, its will be of great utility for the one mentioned laboratory. (Author)

  3. Fluorescence enhancement effect for the determination of curcumin with yttrium(III)-curcumin-sodium dodecyl benzene sulfonate system

    Wang Feng; Huang Wei; Wang Yanwei

    2008-01-01

    It is found that the fluorescence of curcumin is greatly enhanced by yttrium(III) (Y 3+ ) in the presence of sodium dodecyl benzene sulfonate. Based on this, a sensitive fluorimetric method for the determination of curcumin in aqueous solution is proposed. In the potassium hydrogen phthalate (KHP) buffer, the fluorescence intensity of curcumin is proportional to the concentration of curcumin in the range of 7.37x10 -4 -0.18, 0.18-2.95 μg mL -1 and the detection limit is 0.1583 ng mL -1 . The actual samples are satisfactorily determined. In addition, the interaction mechanism is also studied

  4. Fluorescence Chemosensory Determination of Cu2+ Using a New Rhodamine–Morpholine Conjugate

    Zeinab Shekari

    2017-09-01

    Full Text Available A new rhodamine-B carbonyl-morpholine derivative (denoted as RECM was prepared by a two-step synthesis procedure. The employed method allowed a lactam ring development of rhodamine-B and ethylenediamine to demonstrate a facile amide bond formation. The obtained RECM was confirmed by 1H NMR, 13C NMR, and mass spectrometry analysis. RECM was formed to detect copper ion (Cu2+ due to its problematic toxicity features in aquatic ecosystems. It showed a high selectivity toward Cu2+ in comparison with some environmentally relevant alkali, alkaline earth, and transition metal cations at 50 µM in acetonitrile. Moreover, non-fluorescent RECM showed fluorescence intensity and UV-Vis absorbance increases in the presence of Cu2+ with high linear dependent coefficients (R2 = 0.964 and R2 = 0.982 respectively as well as a color change from colorless to pink owing to the ring opening of the rhodamine spirolactam form. Binding capability experiments presented a clear 1:1 stoichiometry of RECM–Cu2+ complex with the binding constant (Ka as 2.25 × 104 M−1. The calculation of limits of detection (LOD was 0.21 µM based on the linear regression method, which is below the maximum contaminant level goal (MCLG value of Cu2+ (1.3 ppm equals to 20.46 µM in drinking water. These characteristics make the RECM a promising candidate for the real-time detection of toxic Cu2+ in environmental monitoring applications.

  5. Methodology for determination of inorganic elements in vitamin supplements by X-ray fluorescence

    Endo, Lucas Y.; Portezan Filho, Otavio; Perreira, Paulo S.; Lopes, Fabio; Appoloni, Carlos R.; Melquiades, Fabio L.

    2009-01-01

    A methodology is present for qualification of inorganic elements in alimentary supplements, using a portable system of low power X-ray, in the analysis of two commercial products, both found as pills. The PXRF (Portable X-ray Fluorescence) is a X-ray mini tube, Ag filter at tube exit, a Si-Pin semiconductor and a Ag collimator at the detector entry, specific circuitry for this type of system and a microcomputer for the data acquisition and analysis. Samples and standards were diluted in boric acid, and the samples were prepared in a 1:10 rate, and the standards vary of 1:2, 1;5, 1:10. 1:15 and 1:100. Results were obtained for Ca, Ti, Mn, Fe, Cu e Zn, with values varying from 0.14 to 8.45 for the sample A, and from 0.17 to 17.94 for the sample B. The PXRF portable system demonstrated to be a multi elementary analysis tool with high analytical speed, and can be applied in situ no only for quality control but also for monitoring of inspection organism

  6. Hue-shifted monomeric variants of Clavularia cyan fluorescent protein: identification of the molecular determinants of color and applications in fluorescence imaging

    Davidson Michael W

    2008-03-01

    mutagenesis study, we conclude that the two histidine residues in close proximity to the chromophore are approximately equal determinants of the blue-shifted fluorescence emission of mTFP1. With respect to live cell imaging applications, the mTFP1-derived mWasabi should be particularly useful in two-color imaging in conjunction with a Sapphire-type variant or as a fluorescence resonance energy transfer acceptor with a blue FP donor. In all fusions attempted, both mTFP1 and mWasabi give patterns of fluorescent localization indistinguishable from that of well-established avGFP variants.

  7. Synchrotron x-ray microbeam characteristics for x-ray fluorescence analysis

    Iida, Atsuo; Noma, Takashi

    1995-01-01

    X-ray fluorescence analysis using a synchrotron x-ray microprobe has become an indispensable technique for non-destructive micro-analysis. One of the most important parameters that characterize the x-ray microbeam system for x-ray fluorescence analysis is the beam size. For practical analysis, however, the photon flux, the energy resolution and the available energy range are also crucial. Three types of x-ray microbeam systems, including monochromatic and continuum excitation systems, were compared with reference to the sensitivity, the minimum detection limit and the applicability to various types of x-ray spectroscopic analysis. 16 refs., 5 figs

  8. Initial idea to use optical flats for x-ray fluorescence analysis and recent applications to diffraction studies

    Horiuchi, T.

    1993-01-01

    Described in this work is the initial idea of using an optical flat for X-ray fluorescence analysis based upon studies of anomalous surface reflection (ASR). To develop total-reflection X-ray fluorescence analysis (TXRF) as one of the most powerful tools for microchemical analysis, various experiments such as the micro-determinations of uranium in sea-water, iron in human blood and rare earth elements in hot spring-water were attempted. Furthermore, the physically interesting experiment on Compton scattering under total-reflection conditions was conducted. Recent applications of the total-reflection phenomenon to diffraction studies, i.e. total-reflection X-ray diffraction (TXRD), are also presented. (author)

  9. Study of the correlation between the coal calorific value and coal ash content using X-ray fluorescence analysis

    Bolortuya, D.; Zuzaan, P.; Gustova, M.V.; Maslov, O.D.

    2013-01-01

    In this paper we have studied the possibility of determining the chemical elements in coal samples using X-ray fluorescence analysis and have found a relationship between the coal calorific value and its ash content with the coal moisture accounting. The amount of coal ash can be determined by the content of the basic chemical elements, such as Si, Sr, Fe, and Ca. It was concluded that the calorific value of coal can be estimated from the ash content in coal without the calorimetric measurements. These correlation coefficients were calculated for several coal mines in Mongolia. The results are in good agreement with the results of chemical analysis

  10. Determination of arsenic speciation in sulfidic waters by Ion Chromatography Hydride-Generation Atomic Fluorescence Spectrometry (IC-HG-AFS).

    Keller, Nicole S; Stefánsson, Andri; Sigfússon, Bergur

    2014-10-01

    A method for the analysis of arsenic species in aqueous sulfide samples is presented. The method uses an ion chromatography system connected with a Hydride-Generation Atomic Fluorescence Spectrometer (IC-HG-AFS). With this method inorganic As(III) and As(V) species in water samples can be analyzed, including arsenite (HnAs(III)O3(n-3)), thioarsenite (HnAs(III)S3(n-3)), arsenate (HnAs(V)O4(n-3)), monothioarsenate (HnAs(V)SO3(n-3)), dithioarsenate (HnAs(V)S2O2(n-3)), trithioarsenate (HnAs(V)S3O(n-3)) and tetrathioarsenate (HnAs(V)S4(n-3)). The peak identification and retention times were determined based on standard analysis of the various arsenic compounds. The analytical detection limit was ~1-3 µg L(-1) (LOD), depending on the quality of the baseline. This low detection limit makes this method also applicable to discriminate between waters meeting the drinking water standard of max. 10 µg L(-1) As, and waters that do not meet this standard. The new method was successfully applied for on-site determination of arsenic species in natural sulfidic waters, in which seven species were unambiguously identified. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Electrothermal atomization laser-excited atomic fluorescence spectroscopy for the determination of indium

    Aucelio, R.Q.; Smith, B.W.; Winefordner, J.D.

    1998-01-01

    A dye laser pumped by a high-repetition-rate copper vapor laser was used as the excitation source to determine indium at parts-per-trillion level by electrothermal atomization laser-excited atomic fluorescence spectrometry (ETA-LEAFS). A comparison was made between wall atomization, in pyrolytic and nonpyrolytic graphite tubes, and platform atomization. The influence of several chemical modifiers either in solution or precoated in the graphite tube was evaluated. The influence of several acids and NaOH in the analyte solution was also studied. Optimization of the analytical conditions was carried out to achieve the best signal-to-background ratio and consequently an absolute limit of detection of 1 fg. Some possible interferents of the method were evaluated. The method was evaluated by determining indium in blood, urine, soil, and urban dust samples. Recoveries between 99.17 and 109.17% are reported. A precision of 4.1% at the 10 ng g -1 level in water standards was achieved. copyright 1998 Society for Applied Spectroscopy

  12. Elemental concentration analysis in prostate tissues using total reflection X-ray fluorescence

    Leitão, R.G.; Palumbo, A.; Souza, P.A.V.R.; Pereira, G.R.; Canellas, C.G.L.; Anjos, M.J.; Nasciutti, L.E.; Lopes, R.T.

    2014-01-01

    Prostate cancer (PCa) currently represents the second most prevalent malignant neoplasia in men, representing 21% of all cancer cases. Benign Prostate Hyperplasia (BPH) is an illness prevailing in men above the age of 50, close to 90% after the age of 80. The prostate presents a high zinc concentration, about 10-fold higher than any other body tissue. In this work, samples of human prostate tissues with cancer, BPH and normal tissue were analyzed utilizing total reflection X-ray fluorescence spectroscopy using synchrotron radiation technique (SR-TXRF) to investigate the differences in the elemental concentrations in these tissues. SR-TXRF analyses were performed at the X-ray fluorescence beamline at Brazilian National Synchrotron Light Laboratory (LNLS), in Campinas, São Paulo. It was possible to determine the concentrations of the following elements: P, S, K, Ca, Fe, Cu, Zn and Rb. By using Mann–Whitney U test it was observed that almost all elements presented concentrations with significant differences (α=0.05) between the groups studied. - Highlights: ► Prostate cancer is the most frequently diagnosed form of cancer in men. ► Intracellular Zn is correlated with proliferation, differentiation, or apoptosis. ► The prostate gland accumulate high concentration of Zn. ► SR-TXRF is a technique widely used in the analysis of low concentration in samples

  13. Multielemental analysis in cigarettes using total reflection X-ray fluorescence with synchrotron radiation

    Barbosa, R.F.; Anjos, M.J. dos; Jesus, E.F.O. de; Lopes, R.T.; Moreira, S.

    2008-01-01

    Full text: It is well known that trace elements have important ejects in the life processes. Some of these elements are toxic for the human even at a very low level of intake. It is known that tobacco plant easily absorbs the heavy metals from the soil, especially Cd and Ni, accumulating them in its leaves. Part of these metals are transferred from tobacco to human body where they will be accumulated and damage some organs, mainly kidneys and liver. In this way, cigarettes are responsible for the death of millions of people in the world, about one death every eight seconds. The aim of this work was to determine the elemental concentrations of ten different elements in tobacco of Brazilian cigarettes used Total Reflection X-Ray Fluorescence with Synchrotron Radiation method. The fluorescence measurements were carried out at Brazilian Synchrotron Light Laboratory, Campinas - Sao Paulo. A qualitative analysis of spectral peaks showed that the samples contained potassium, calcium, titanium, chromium, manganese, iron, copper, rubidium and strontium. Among these elements, calcium, potassium and iron presented the highest concentrations. There was a wide range in the elemental concentrations in the tobacco, due various factors, such as agricultural practices, soil characteristics, climatic conditions and plant varieties. Our results are in good concern with the results reported by the scientific literature

  14. Determination of iron in seawater by electrothermal atomic absorption spectrometry and atomic fluorescence spectrometry: A comparative study

    Cabon, J.Y.; Giamarchi, P.; Le Bihan, A.

    2010-01-01

    Two methods available for direct determination of total Fe in seawater at low concentration level have been examined: electrothermal atomization atomic absorption spectrometry (ETAAS) and electrothermal atomization laser excited atomic fluorescence spectrometry (ETA-LEAFS). In a first part, we have optimized experimental conditions of ETAAS (electrothermal program, matrix chemical modification) for the determination of Fe in seawater by minimizing the chemical interference effects and the magnitude of the simultaneous background absorption signal. By using the best experimental conditions, a detection limit of 80 ng L -1 (20 μL, 3σ) for total Fe concentration was obtained by ETAAS. Using similar experimental conditions (electrothermal program, chemical modification), we have optimized experimental conditions for the determination of Fe by LEAFS. The selected experimental conditions for ETA-LEAFS: excitation wavelength (296.69 nm), noise attenuation and adequate background correction led to a detection limit (3σ) of 3 ng L -1 (i.e. 54 pM) for total Fe concentration with the use a 20 μL seawater sample. For the two methods, concentration values obtained for the analysis of Fe in a NASS-5 (0.2 μg L -1 ) seawater sample were in good agreement with the certified values.

  15. Determination of iron in seawater by electrothermal atomic absorption spectrometry and atomic fluorescence spectrometry: a comparative study.

    Cabon, J Y; Giamarchi, P; Le Bihan, A

    2010-04-07

    Two methods available for direct determination of total Fe in seawater at low concentration level have been examined: electrothermal atomization atomic absorption spectrometry (ETAAS) and electrothermal atomization laser excited atomic fluorescence spectrometry (ETA-LEAFS). In a first part, we have optimized experimental conditions of ETAAS (electrothermal program, matrix chemical modification) for the determination of Fe in seawater by minimizing the chemical interference effects and the magnitude of the simultaneous background absorption signal. By using the best experimental conditions, a detection limit of 80 ng L(-1) (20 microL, 3sigma) for total Fe concentration was obtained by ETAAS. Using similar experimental conditions (electrothermal program, chemical modification), we have optimized experimental conditions for the determination of Fe by LEAFS. The selected experimental conditions for ETA-LEAFS: excitation wavelength (296.69 nm), noise attenuation and adequate background correction led to a detection limit (3sigma) of 3 ng L(-1) (i.e. 54 pM) for total Fe concentration with the use a 20 microL seawater sample. For the two methods, concentration values obtained for the analysis of Fe in a NASS-5 (0.2 microg L(-1)) seawater sample were in good agreement with the certified values. Copyright 2010 Elsevier B.V. All rights reserved.

  16. Molecular Detection of Bladder Cancer by Fluorescence Microsatellite Analysis and an Automated Genetic Analyzing System

    Sarel Halachmi

    2007-01-01

    Full Text Available To investigate the ability of an automated fluorescent analyzing system to detect microsatellite alterations, in patients with bladder cancer. We investigated 11 with pathology proven bladder Transitional Cell Carcinoma (TCC for microsatellite alterations in blood, urine, and tumor biopsies. DNA was prepared by standard methods from blood, urine and resected tumor specimens, and was used for microsatellite analysis. After the primers were fluorescent labeled, amplification of the DNA was performed with PCR. The PCR products were placed into the automated genetic analyser (ABI Prism 310, Perkin Elmer, USA and were subjected to fluorescent scanning with argon ion laser beams. The fluorescent signal intensity measured by the genetic analyzer measured the product size in terms of base pairs. We found loss of heterozygocity (LOH or microsatellite alterations (a loss or gain of nucleotides, which alter the original normal locus size in all the patients by using fluorescent microsatellite analysis and an automated analyzing system. In each case the genetic changes found in urine samples were identical to those found in the resected tumor sample. The studies demonstrated the ability to detect bladder tumor non-invasively by fluorescent microsatellite analysis of urine samples. Our study supports the worldwide trend for the search of non-invasive methods to detect bladder cancer. We have overcome major obstacles that prevented the clinical use of an experimental system. With our new tested system microsatellite analysis can be done cheaper, faster, easier and with higher scientific accuracy.

  17. Simultaneous determination of arsenic and antimony by hydride generation atomic fluorescence spectrometry with dielectric barrier discharge atomizer

    Xing Zhi [Department of Chemistry, Key Laboratory for Atomic and Molecular Nanosciences of the Education Ministry, Tsinghua University, Beijing 100084 (China); Kuermaiti, Biekesailike [Department of Chemistry, Key Laboratory for Atomic and Molecular Nanosciences of the Education Ministry, Tsinghua University, Beijing 100084 (China); Products Quality Inspection Institute, Yili, Xinjiang 835000 (China); Wang Juan; Han Guojun; Zhang Sichun [Department of Chemistry, Key Laboratory for Atomic and Molecular Nanosciences of the Education Ministry, Tsinghua University, Beijing 100084 (China); Zhang Xinrong, E-mail: xrzhang@mail.tsinghua.edu.cn [Department of Chemistry, Key Laboratory for Atomic and Molecular Nanosciences of the Education Ministry, Tsinghua University, Beijing 100084 (China)

    2010-12-15

    Simultaneous determination of As and Sb by hydride generation atomic fluorescence spectrometry was developed with the dielectric barrier discharge plasma as the hydride atomizer. The low-temperature and atmospheric-pressure micro-plasma was generated in a quartz cylindrical configuration device, which was constructed by an axial internal electrode and an outer electrode surrounding outside of the tube. The optimization of the atomizer construction and parameters for hydride generation and fluorescence detection systems were carried out. Under the optimized conditions, the detection limits for As and Sb were 0.04 and 0.05 {mu}g L{sup -1}, respectively. In addition, the applicability of the present method was confirmed by the detection of As and Sb in reference materials of quartz sandstone (GBW07106) and argillaceous limestone (GBW07108). The present work provided a new approach to exploit the miniaturized hydride generation dielectric barrier discharge atomic fluorescence spectrometry system for simultaneous multi-element determination.

  18. Simultaneous determination of arsenic and antimony by hydride generation atomic fluorescence spectrometry with dielectric barrier discharge atomizer

    Xing Zhi; Kuermaiti, Biekesailike; Wang Juan; Han Guojun; Zhang Sichun; Zhang Xinrong

    2010-01-01

    Simultaneous determination of As and Sb by hydride generation atomic fluorescence spectrometry was developed with the dielectric barrier discharge plasma as the hydride atomizer. The low-temperature and atmospheric-pressure micro-plasma was generated in a quartz cylindrical configuration device, which was constructed by an axial internal electrode and an outer electrode surrounding outside of the tube. The optimization of the atomizer construction and parameters for hydride generation and fluorescence detection systems were carried out. Under the optimized conditions, the detection limits for As and Sb were 0.04 and 0.05 μg L -1 , respectively. In addition, the applicability of the present method was confirmed by the detection of As and Sb in reference materials of quartz sandstone (GBW07106) and argillaceous limestone (GBW07108). The present work provided a new approach to exploit the miniaturized hydride generation dielectric barrier discharge atomic fluorescence spectrometry system for simultaneous multi-element determination.

  19. Superresolution size determination in fluorescence microscopy: A comparison between spatially modulated illumination and confocal laser scanning microscopy

    Spoeri, Udo; Failla, Antonio Virgilio; Cremer, Christoph

    2004-01-01

    Recently developed far field light optical methods are a powerful tool to analyze biological nanostructures and their dynamics, in particular including the interior of three-dimensionally conserved cells. In this article, the recently described method of spatially modulated illumination (SMI) microscopy has been further extended to the online determination of the extension of small, subwavelength sized, fluorescent objects (nanosizing). Using fluorescence excitation with 488 nm, the determination of fluorescent labeled object diameters down to 40 nm corresponding to about 1/12th of the wavelength used for one-photon excitation could be shown. The results of the SMI nanosizing procedure for a detailed, systematic variation of the object diameter are presented together with a fast algorithm for online size evaluation. In addition, we show a direct comparison of the diameter of 'colocalization volumes' between SMI nanosizing and conventional confocal laser scanning microscopy

  20. Application of radionuclide sources for excitation in energy-dispersive X-ray fluorescence analysis

    Hoffmann, P.

    1986-01-01

    X-ray fluorescence (XRF) analysis is in broad application in many fields of science where elemental determinations are necessary. Solid and liquid samples are analyzed by this method. Solids are introduced in thin or thick samples as melted glass, pellets, powders or as original specimen. The excitation of X-ray spectra can be performed by specific and polychromic radiation of X-ray tubes, by protons, deuterons, α-particles, heavy ions and synchrotron radiation from accelerators and by α-particles, X- and γ-rays and by bremsstrahlung generated by β - -particles from radionuclide sources. The radionuclides are devided into groups with respect to their decay mode and the energy of the emitted radiation. The broad application of radionuclides in XRF excitation is shown in examples as semi-quantitative analysis of glasses, as quantitative analysis of coarse ceramics and as quantitative determination of heavy elements (mainly actinides) in solutions. The advantages and disadvantages of radionuclide excitation in XRF analysis are discussed. (orig.) [de

  1. Evaluation of diatomea algae Thalassiosira weissflogii sensitivity to chloride mercury and methylmercury by chlorophyll fluorescence analysis

    Graevskaya, E. E.; Antal, T. K.; Matorin, D. N.; Voronova, E. N.; Pogosyan, S. I.; Rubin, A. B.

    2003-05-01

    Measurement of chlorophyll fluorescence has been shown to be a rapid, non-invasive, and reliable method to assess photosynthetic performance in a changing environment. In our study, the pulseamplitude-modulation (PAM) - fluorometric method was used to evaluate the sensitivity to chloride mercury and methylmercury chloride of diatomea microalgae Thalassiosira weissflogii. We found that 10^{-6} and 10^{-7} M MeHg led to a slow decrease in the PS II activity following for prolonged lag phase, whereas the algae was not sensitive to the same concentrations of HgCl2. However observed PS II inactivation by methylmercury was not complete and about 10 percents ofthe cells kept the high level of PS II activity as it was shown by microfluorometric analysis. These cells could determine adaptation of algae to methylmercury effect. Both toxicants decreased the rate of PS II reparation, as well as increased a heat pathway of excitation dissipation in PS II antennae complex.

  2. Fluorescence spectroscopy as a tool for determination of organic matter removal efficiency at water treatment works

    M. Z. Bieroza

    2010-04-01

    Full Text Available Organic matter (OM in drinking water treatment is a common impediment responsible for increased coagulant and disinfectant dosages, formation of carcinogenic disinfection-by products, and microbial re-growth in distribution system. The inherent heterogeneity of OM implies the utilization of advanced analytical techniques for its characterization and assessment of removal efficiency. Here, the application of simple fluorescence excitation-emission technique to OM characterization in drinking water treatment is presented. The fluorescence data of raw and clarified water was obtained from 16 drinking water treatment works. The reduction in fulvic-like fluorescence was found to significantly correlate with OM removal measured with total organic carbon (TOC. Fluorescence properties, fulvic- and tryptophan-like regions, were found to discriminate OM fractions of different removal efficiencies. The results obtained in the study show that fluorescence spectroscopy provides a rapid and accurate characterization and quantification of OM fractions and indication of their treatability in conventional water treatment.

  3. Determination of fluorine concentrations using wavelength dispersive X-ray fluorescence (WDXRF) spectrometry to analyze fluoride precipitates.

    Lee, H. A.; Lee, J.; Kwon, E.; Kim, D.; Yoon, H. O.

    2015-12-01

    In recent times, fluorine has been receiving increasing attention due to the possibility for chemical (HF) leakage accidents and its high toxicity to human and environment. In this respect, a novel approach for the determination of fluorine concentrations in water samples using wavelength dispersive X-ray fluorescence (WDXRF) spectrometry was investigated in this study. The main disadvantage of WDXRF technique for fluorine analysis is low analytical sensitivity for light elements with atomic number (Z) less than 15. To overcome this problem, we employed the precipitation reaction which fluoride is reacted with cation such as Al3+ and/or Ca2+ prior to WDXRF analysis because of their high analytical sensitivity. The cation was added in fluoride solutions to form precipitate (AlF3 and/or CaF2) and then the solution was filtered through Whatman filter. After drying at 60 °C for 5 min, the filter was coated with X-ray film and directly analyzed using WDXRF spectrometry. Consequently, we analyzed the cation on filter and subsequently fluorine concentration was calculated inversely based on chemical form of precipitate. This method can improve the analytical sensitivity of WDXRF technique for fluorine analysis and be applicable to various elements that can make precipitate.

  4. Multi-color fluorescent DNA analysis in an integrated optofluidic lab on a chip

    Dongre, C.

    2010-01-01

    Abstract: Sorting and sizing of DNA molecules within the human genome project has enabled the genetic mapping of various illnesses. Furthermore by employing tiny lab-on-a-chip device, integrated DNA sequencing and genetic diagnostics have become feasible. We present the combination of capillary electrophoresis with laser-induced fluorescence for optofluidic integration toward an on-chip bio-analysis tool. Integrated optical fluorescence excitation allows for a high spatial resolution (12 μm) ...

  5. Microstructural analysis of clayey ceramic incorporated with fluorescent lamp glass

    Morais, A.S.C.; Caldas, T.C.C.; Pereira, P.S.; Monteiro, S.N.; Vieira, C.M.F.

    2011-01-01

    This study aims to evaluate the effect of the incorporation of glass powder fluorescent lamp, from a decontamination process, in the microstructure of clayey ceramic. Formulations were prepared with incorporation of the waste in amounts of up to 10 wt.% into the clayey body. Specimens were prepared by uniaxial mold-press at 20 MPa and then fired at 850 and 1050°C. After firing, the microstructure of the ceramics was evaluated by optical microscopy (OM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results showed that the incorporation of glass powder into the clayey body changes the microstructure of the ceramics. (author)

  6. Extraction X-ray fluorescence determination of gold in natural samples

    Dmitriev, S.N.; Shishkina, T.V.; Zhuravleva, E.L.; Chimehg, Zh.

    1990-01-01

    The behaviour of gold and other elements impeding its X-ray fluorescence (XRF) determination, namely, of zinc, lead, and arsenic, has been studied during their extraction by TBP from hydrochloric, nitric, and aqua regia solutions using solid extractant (SE(TBP)). Gold extraction from pulps after aqua regia leaching, with the gold distribution coefficient (D) being equal to about 10 4 , was observed as the most favourable one for the quantitative and selective recovery of gold. For extraction from hydrochloric solutions the D Au value does not depend on the gold content of initial solutions (10 -8 - 10 -4 M), but it decreases substantially with increasing extraction temperature (from 5x10 5 at 20 deg C to 9x10 3 at 70 deg C). An anomalously high distribution coefficient of lead (D Pb =10 3 ) was observed during extraction from hydrochloric solutions in the presence of chlorine. This fact could be explained by the formation of the chlorocomplexes of lead (IV). The XRF method of gold determination in natural samples has been developed, which includes the aqua regia decomposition of the samples, recovery of gold from the pulp after its leaching by SE(TBP) and back - extraction using a 0.025 M hot thiourea solution providing a thin sample film for secondary XRF spectrometry. For 25 g of the sample material the limit of determination is set at 0.01 g per ton (10 -6 %). The accuracy of the technique has been checked on different reference materials. The results agree within 10%. 16 refs.; 5 figs.; 1 tab

  7. High performance liquid chromatography--atomic fluorescence spectrometric determination of arsenic species in beer samples

    Melo Coelho, N.M.; Parrilla, Carmen; Cervera, M.L.; Pastor, A.; Guardia, M. de la

    2003-01-01

    A method has been developed for the direct determination of As(III), dimethylarsinic acid (DMA), monomethylarsonic acid (MMA) and As(V) in beers by hydride generation--atomic fluorescence spectrometry after separation of arsenic species by high performance liquid chromatography. Compounds were separated by anion-exchange chromatography with isocratic elution using KH 2 PO 4 /K 2 HPO 4 as mobile phase with elution times of 1.67, 2.08, 6.52 and 10.72 min for As(III), DMA, MMA and As(V), respectively. Parameters affecting the hydride generation of all arsenic species were studied and the best conditions were established as a reaction coil of 150 cm, for a sample injected volume of 100 μl, a 4.0% (m/v) solution of sodium tetrahydroborate and 2.0 mol l -1 hydrochloric acid with flow rates of 2.7 and 1.7 ml min -1 , respectively and a flow rate of 500 ml min -1 for the argon carrier gas. Under the best experimental conditions, the detection limit was found to be 0.12, 0.20, 0.27 and 0.39 μg l -1 for As(III), DMA, MMA and As(V), respectively. The relative standard deviation for eight independent determinations varied from 3.9 till 8.9% for species considered at a concentration level of 10.0 μg l -1 . Recovery and comparative studies evidenced that the method is suitable for the accurate determination of arsenic species in water and beer samples

  8. High performance liquid chromatography--atomic fluorescence spectrometric determination of arsenic species in beer samples

    Melo Coelho, N.M.; Parrilla, Carmen; Cervera, M.L.; Pastor, A.; Guardia, M. de la

    2003-04-10

    A method has been developed for the direct determination of As(III), dimethylarsinic acid (DMA), monomethylarsonic acid (MMA) and As(V) in beers by hydride generation--atomic fluorescence spectrometry after separation of arsenic species by high performance liquid chromatography. Compounds were separated by anion-exchange chromatography with isocratic elution using KH{sub 2}PO{sub 4}/K{sub 2}HPO{sub 4} as mobile phase with elution times of 1.67, 2.08, 6.52 and 10.72 min for As(III), DMA, MMA and As(V), respectively. Parameters affecting the hydride generation of all arsenic species were studied and the best conditions were established as a reaction coil of 150 cm, for a sample injected volume of 100 {mu}l, a 4.0% (m/v) solution of sodium tetrahydroborate and 2.0 mol l{sup -1} hydrochloric acid with flow rates of 2.7 and 1.7 ml min{sup -1}, respectively and a flow rate of 500 ml min{sup -1} for the argon carrier gas. Under the best experimental conditions, the detection limit was found to be 0.12, 0.20, 0.27 and 0.39 {mu}g l{sup -1} for As(III), DMA, MMA and As(V), respectively. The relative standard deviation for eight independent determinations varied from 3.9 till 8.9% for species considered at a concentration level of 10.0 {mu}g l{sup -1}. Recovery and comparative studies evidenced that the method is suitable for the accurate determination of arsenic species in water and beer samples.

  9. Strategies of molecular imprinting-based fluorescence sensors for chemical and biological analysis.

    Yang, Qian; Li, Jinhua; Wang, Xiaoyan; Peng, Hailong; Xiong, Hua; Chen, Lingxin

    2018-07-30

    One pressing concern today is to construct sensors that can withstand various disturbances for highly selective and sensitive detecting trace analytes in complicated samples. Molecularly imprinted polymers (MIPs) with tailor-made binding sites are preferred to be recognition elements in sensors for effective targets detection, and fluorescence measurement assists in highly sensitive detection and user-friendly control. Accordingly, molecular imprinting-based fluorescence sensors (MI-FL sensors) have attracted great research interest in many fields such as chemical and biological analysis. Herein, we comprehensively review the recent advances in MI-FL sensors construction and applications, giving insights on sensing principles and signal transduction mechanisms, focusing on general construction strategies for intrinsically fluorescent or nonfluorescent analytes and improvement strategies in sensing performance, particularly in sensitivity. Construction strategies are well overviewed, mainly including the traditional indirect methods of competitive binding against pre-bound fluorescent indicators, employment of fluorescent functional monomers and embedding of fluorescence substances, and novel rational designs of hierarchical architecture (core-shell/hollow and mesoporous structures), post-imprinting modification, and ratiometric fluorescence detection. Furthermore, MI-FL sensor based microdevices are discussed, involving micromotors, test strips and microfluidics, which are more portable for rapid point-of-care detection and in-field diagnosing. Finally, the current challenges and future perspectives of MI-FL sensors are proposed. Copyright © 2018 Elsevier B.V. All rights reserved.

  10. Analysis of the Color and Fluorescence Alterations of Enamel and Dentin Treated With Hydrogen Peroxide.

    Caneppele, Taciana Marco Ferraz; Rocha Gomes Torres, Carlos; Bresciani, Eduardo

    2015-10-01

    The aim of this study was to evaluate the effect of hydrogen peroxide whitening on fluorescence and color of bovine enamel and dentin. Twenty five dentin discs and 25 enamel discs, with 6 mm diameter and 1 mm thick, were obtained. Direct fluorescence (spectrofluorophotometry) and color (spectrophotometry) were assessed. After fluorescence and color baseline measurements, specimens were immersed in a 35% hydrogen peroxide (HP) solution for 1 h. This procedure was repeated after 7 days. Final fluorescence and color measurements were performed after the second immersion. Chemical characterization of 5 additional specimens was also performed. Data were submitted to repeated analysis of variance and Tukey's test for fluorescence and unpaired t-test for color and chemical components (pwhitening. Enamel presented lower fluorescence than dentin at baseline, but this parameter did not decrease after whitening. Color changes were observed for both substrates, with significantly greater whitening effect in dentin (ΔE=10.37) (pWhitening by hydrogen peroxide induced significant decrease in fluorescence of tooth dentin and promoted significant color changes in dentin and enamel with more accentuated outcomes in dentin.

  11. Plasmonic-based instrument response function for time-resolved fluorescence: toward proper lifetime analysis

    Szlazak, Radoslaw; Tutaj, Krzysztof; Grudzinski, Wojciech; Gruszecki, Wieslaw I.; Luchowski, Rafal, E-mail: rafal.luchowski@umcs.pl [Maria Curie-Sklodowska University, Department of Biophysics, Institute of Physics (Poland)

    2013-06-15

    In this report, we investigated the so-called plasmonic platforms prepared to target ultra-short fluorescence and accurate instrumental response function in a time-domain spectroscopy and microscopy. The interaction of metallic nanoparticles with nearby fluorophores results in the increase of the dye fluorescence quantum yield, photostability and decrease of the lifetime parameter. The mentioned properties of platforms were applied to achieve a picosecond fluorescence lifetime (21 ps) of erythrosin B, used later as a better choice for deconvolution of fluorescence decays measured with 'color' sensitive photo-detectors. The ultra-short fluorescence standard based on combination of thin layers of silver film, silver colloidal nanoparticles (about 60 nm in diameter), and top layer of erythrosin B embedded in 0.2 % poly(vinyl) alcohol. The response functions were monitored on two photo-detectors; microchannel plate photomultiplier and single photon avalanche photodiode as a Rayleigh scattering and ultra-short fluorescence. We demonstrated that use of the plasmonic base fluorescence standard as an instrumental response function results in the absence of systematic error in lifetime measurements and analysis.

  12. Spectrofluorimetric determination of trace amount of coenzyme II using ciprofloxacin-terbium complex as a fluorescent probe

    Bian Weiwei; Wang Yusheng; Zhu Xiaojing; Jiang Chongqiu

    2006-01-01

    A new spectrofluorimetric method was developed for the determination of trace amount of nicotinamide adenine dinucleotide phosphate (NADP). Using terbium ion (Tb 3+ )-ciprofloxacin (CIP) complex as a fluorescent probe, in the buffer solution of pH=9.00, NADP can remarkably enhance the fluorescence intensity of the Tb 3+ -CIP complex at λ=545nm and the enhanced fluorescence intensity of Tb 3+ ion is in proportion to the concentration of NADP. Optimum conditions for the determination of NADP were also investigated. The dynamic range for the determination of NADP is 4.9x10 -7 -3.7x10 -6 molL -1 with detection limit of 1.3x10 -7 molL -1 . This method is simple, practical and relatively free interference from coexisting substances and can be successfully applied to determination of NADP in synthetic water samples. Moreover, the enhancement mechanisms of the fluorescence intensity in the Tb 3+ -CIP system and the Tb 3+ -CIP-NADP system have been also discussed

  13. Analysis of discrete and continuous laser induced fluorescence spectra of the A 1Σsub(u)+-X 1Σsub(g)+ band system of Sr2

    Gerber, G.; Moeller, R.

    1982-01-01

    Laser induced fluorescence spectra of the gaseous Sr 2 excimer molecule have been measured. The spectra contain discrete molecular fluorescence series, regularly modulated continuous fluorescence and an unstructured continuum. Analysis of the molecular line spectra yields for the first time Dunham coefficients for the X 1 Σsub(g) + ground state and the A 1 Σsub(u) + excited state. Using the intensity distribution of the modulated continuum which is associated with bound-free transitions the repulsive potential of the ground state up to 3000 cm -1 above the dissociation limit has been determined. The unstructured continuum can be analyzed as due to two types of continuous fluorescence. The dissociation energy of Sr 2 has been determined to Dsub(e)(X) = 965 +- 45 cm -1 . (Auth.)

  14. Analysis of discrete and continuous laser induced fluorescence spectra of the A 1μ+sub(u) - X 1μ+sub(g) band system of SR2

    Gerber, G.; Moeller, R.

    1982-01-01

    Laser induced fluorescence spectra of the gaseous Sr 2 excimer molecule have been measured. The spectra contain discrete molecular fluorescence series, regularly modulated continuous fluorescence and an unstructured continuum. Analysis of the molecular line spectra yields for the first time Dunham coefficients for the X 1 μ + sub(g) ground state and the A 1 μ + sub(u) excited state. Using the intensity distribution of the modulated continuum which is associated with bound-free transitions the repulsive potential of the ground state up to 3000 cm - 1 above the dissociation limit has been determined. The unstructured continuum can be analyzed as due to two types of continuous fluorescence. The dissociation energy of Sr 2 has been determined to Dsub(e) (X) = 965 +- 45 cm - 1 . (Author)

  15. Synovitis in mice with inflammatory arthritis monitored with quantitative analysis of dynamic contrast-enhanced NIR fluorescence imaging using iRGD-targeted liposomes as fluorescence probes

    Wu H

    2018-03-01

    Full Text Available Hao Wu,1,2,* Haohan Wu,1,2,* Yanni He,1 Zhen Gan,2 Zhili Xu,1,2 Meijun Zhou,1,2 Sai Liu,1,2 Hongmei Liu1 1Department of Ultrasonography, Guangdong Second Provincial General Hospital Affiliated to Southern Medical University, Guangzhou, China; 2Department of Ultrasonography, The Third Affiliated Hospital of Southern Medical University, Guangzhou, China *These authors contributed equally to this work Background: Rheumatoid arthritis (RA is a common inflammatory disorder characterized primarily by synovitis and pannus formation in multiple joints, causing joints destruction and irreversible disability in most cases. Early diagnosis and effective therapy monitoring of RA are of importance for achieving the favorable prognosis. Methods: We first prepared the targeted fluorescence probes, and then explored the feasibility of near-infrared (NIR fluorescence molecular imaging to detect and evaluate the RA via the targeted fluorescence probes by quantitative analysis in this study. Results: The targeted fluorescence probes (indocyanine green-liposomes decorated with iRGD peptide [iLPs] was successfully prepared. The quantitative analysis found that strong fluorescence signal was detected in inflamed paws and the fluorescence signal in iLPs group was 3.03-fold higher than that in non-targeted (indocyanine green-liposomes decorated without iRGD peptide [LPs] group (P<0.01 at 15 min after injection, whereas the fluorescence signal from iLPs signal can almost not be observed in the non-inflamed paws, showing the high sensitivity and accuracy for arthritis by the NIR fluorescence imaging based on iLPs. Conclusion: The NIR fluorescence imaging by iLPs may facilitate improved arthritis diagnosis and early assessment of the disease progression by providing an in vivo characterization of angiogenesis in inflammatory joint diseases. Keywords: rheumatoid arthritis, synovitis, diagnosis, near-infrared fluorescence imaging, iRGD-targeted probes

  16. Applications of Liquid Chromatography with Fluorescence Detector Diodes and the Analysis of Environmental Pollutants

    Garcia, S.; Perez, R. M.

    2012-01-01

    It presents a review on the determination of major types of organic pollutants in environmental samples by HPLC with diode array or fluorescence molecular detectors. Main objective has been to make a compilation of the analytical potential of the technique based on literature and our laboratory studies on the main aspects of analytical methodology used in the determination of these compounds. (Author) 53 refs.

  17. Determination of mercury in rice by cold vapor atomic fluorescence spectrometry after microwave-assisted digestion

    Silva, Maria Jose da [Department of Analytical Chemistry, Edificio de Investigacion, University of Valencia, 50 Dr. Moliner Street, E-46100 Burjassot, Valencia (Spain); Departamento de Quimica Fundamental, Universidade Federal de Pernambuco, Cidade Universitaria, 50740-550 Recife, PE (Brazil); Paim, Ana Paula S. [Departamento de Quimica Fundamental, Universidade Federal de Pernambuco, Cidade Universitaria, 50740-550 Recife, PE (Brazil); Pimentel, Maria Fernanda [Departamento de Engenharia Quimica, Universidade Federal de Pernambuco, Recife, PE (Brazil); Cervera, M. Luisa, E-mail: m.luisa.cervera@uv.es [Department of Analytical Chemistry, Edificio de Investigacion, University of Valencia, 50 Dr. Moliner Street, E-46100 Burjassot, Valencia (Spain); Guardia, Miguel de la [Department of Analytical Chemistry, Edificio de Investigacion, University of Valencia, 50 Dr. Moliner Street, E-46100 Burjassot, Valencia (Spain)

    2010-05-14

    A cold vapor atomic fluorescence spectrometry method (CV-AFS) has been developed for the determination of Hg in rice samples at a few ng g{sup -1} concentration level. The method is based on the previous digestion of samples in a microwave oven with HNO{sub 3} and H{sub 2}O{sub 2} followed by dilution with water containing KBr/KBrO{sub 3} and hydroxylamine and reduction with SnCl{sub 2} in HCl using external calibration. The matrix interferences and the effect of nitrogen oxide vapors have been evaluated and the method validated using a certified reference material. The limit of detection of the method was 0.9 ng g{sup -1} with a recovery percentage of 95 {+-} 4% at an added concentration of 5 ng g{sup -1}. The concentration level of Hg found in 24 natural rice samples from different origin ranged between 1.3 and 7.8 ng g{sup -1}.

  18. Chromatographic determination of nanomolar cyanate concentrations in estuarine and sea waters by precolumn fluorescence derivatization.

    Widner, Brittany; Mulholland, Margaret R; Mopper, Kenneth

    2013-07-16

    Recent studies suggest that cyanate (OCN(-)) is a potentially important source of reduced nitrogen (N) available to support the growth of aquatic microbes and, thus, may play a role in aquatic N cycling. However, aquatic OCN(-) distributions have not been previously described because of the lack of a suitable assay for measuring OCN(-) concentrations in natural waters. Previous methods were designed to quantify OCN(-) in aqueous samples with much higher reduced N concentrations (micromolar levels) than those likely to be found in natural waters (nanomolar levels). We have developed a method to quantify OCN(-) in dilute, saline environments. In the method described here, OCN(-) in aqueous solution reacts with 2-aminobenzoic acid to produce a highly fluorescent derivative, 2,4-quinazolinedione, which is then quantified using high performance liquid chromatography. Derivatization conditions were optimized to simultaneously minimize the reagent blank and maximize 2,4-quinazolinedione formation (>90% reaction yield) in estuarine and seawater matrices. A limit of detection (LOD) of 0.4 nM was achieved with only minor matrix effects. We applied this method to measure OCN(-) concentrations in estuarine and seawater samples from the Chesapeake Bay and coastal waters from the mid-Atlantic region. OCN(-) concentrations ranged from 0.9 to 41 nM. We determined that OCN(-) concentrations were stable in 0.2 μm filtered seawater samples stored at -80 °C for up to nine months.

  19. Simple procedure for nutrient analysis of coffee plant with energy dispersive X-ray fluorescence spectrometry (EDXRF)

    Tezotto, Tiago; Favarin, Jose Laercio; Neto, Ana Paula; Azevedo, Ricardo Antunes, E-mail: tiago.tezotto@usp.br [Escola Superior de Agricultura Luiz de Queiroz (ESALQ/USP), Piracicaba, SP (Brazil); Gratao, Priscila Lupino [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP/ FCAV), Jaboticabal, SP (Brazil). Dept. de Biologia Aplicada a Agropecuaria; Mazzafera, Paulo [Universidade Estadual de Campinas (UNICAMP/IB), SP (Brazil). Dept. Biologia Vegetal

    2013-07-15

    Nutrient analysis is used to estimate nutrient content of crop plants to manage fertilizer application for sustained crop production. Direct solid analysis of agricultural and environmental samples by energy dispersive X-ray fluorescence spectrometry (EDXRF) was chosen as alternative technique to evaluate the simultaneous multielemental quantification of the most important essential elements in coffee (Coffea arabica L.) plants. Inductively coupled plasma atomic emission spectrometry and certified reference materials made from leaves were used to calibrate and check the trueness of EDXRF method for the determination of the concentration of several nutrients in coffee leaves and branches. Fluorescence spectrometry proved to be advantageous and presented low cost as loose powder samples could be used. Samples collected from a field experiment where coffee plants were treated with excess of Ni and Zn were used to verify the practical application of the method. Good relationships were achieved between certified values and data obtained by EDXRF, with recoveries ranging from 82 to 117 %.(author)

  20. Relative evaluation of neutron activation, X-ray fluorescence and spark source mass spectrometry for multielement analysis of geothermal waters

    Blommaert, W.; Vandelannoote, R.; Van't Dack, L.; Gijbels, R.; Van Grieken, R.

    1980-01-01

    To sulfide geothermal waters from the French Pyrenees region and bicarbonate and chloride waters from the French Vosges area, all of the following analysis techniques were applied in order to compose a broad inventory of trace elements: (1) for the dissolved metarial: neutron activation analysis after a freeze-drying step using a very short cycle, short cycle or long cycle, neutron activation after co-crystallization on 1-(2-pyridylazo)-2-naphthol (PAN) using a short cycle or long cycle, X-ray fluorescence after co-crystallization on PAN and spark source mass spectrometry after evaporation on graphite or preconcentration on PAN, and, (2) for the filtered or suspended material: neutron activation using a very short, short or long cycle and X-ray fluorescence. Altogether, on the average some 30 elements could be determined above the detection limit in solution and 15 in suspension. (author)

  1. Total reflection X-ray fluorescence as a convenient tool for determination of trace elements in microscale gasoline and diesel

    Zhang, Airui; Jin, Axiang; Wang, Hai; Wang, Xiaokang; Zha, Pengfei; Wang, Meiling; Song, Xiaoping; Gao, Sitian

    2018-03-01

    Quantitative determination of trace elements like S, Fe, Cu, Mn and Pb in gasoline and S in diesel is of great importance due to the growing concerns over air pollution, human health and engine failure caused by utilization of gasoline and diesel with these harmful elements. A method of total reflection X-ray fluorescence (TXRF) was developed to measure these harmful trace elements in gasoline and diesel. A variety of factors to affect measurement results, including TXRF parameters, microwave-assisted digestion conditions and internal standard element and its addition, were examined to optimize these experimental procedures. The hydrophobic treatment of the surface of quartz reflectors to support the analyte with neutral silicone solutions could prepare thin films of gasoline and diesel digestion solutions for subsequent TXRF analysis. The proposed method shows good potential and reliability to determine the content of harmful trace elements in gasoline and diesel with high sensitivity and accuracy without drawing different standard calibration curves, and can be easily employed to screen gasoline and diesel in routine quality control and assurance.

  2. Determination of arsenic in water samples by Total Reflection X-Ray Fluorescence using pre-concentration with alumina

    Barros, Haydn [Laboratorio de Fisica Nuclear, Dpto. De Fisica, Universidad Simon Bolivar, Sartenejas, Baruta (Venezuela, Bolivarian Republic of); Marco Parra, Lue-Meru, E-mail: luemerumarco@yahoo.e [Universidad Centroccidental Lisandro Alvarado, Dpto. Quimica y Suelos, Decanato de Agronomia, Tarabana, Cabudare, Edo.Lara (Venezuela, Bolivarian Republic of); Bennun, Leonardo [Universidad de Concepcion, Concepcion (Chile); Greaves, Eduardo D. [Laboratorio de Fisica Nuclear, Dpto. De Fisica, Universidad Simon Bolivar, Sartenejas, Baruta (Venezuela, Bolivarian Republic of)

    2010-06-15

    The determination of arsenic in water samples requires techniques of high sensitivity. Total Reflection X-Ray Fluorescence (TXRF) allows the determination but a prior separation and pre-concentration procedure is necessary. Alumina is a suitable substrate for the selective separation of the analytes. A method for separation and pre-concentration in alumina, followed by direct analysis of the alumina is evaluated. Quantification was performed using the Al-K{alpha} and Co-K{alpha} lines as internal standard in samples prepared on an alumina matrix, and compared to a calibration with aqueous standards. Artificial water samples of As (III) and As (V) were analyzed after the treatment. Fifty milliliters of the sample at ppb concentration levels were mixed with 10 mg of alumina. The pH, time and temperature were controlled. The alumina was separated from the slurry by centrifugation, washed with de-ionized water and analyzed directly on the sample holder. A pre-concentration factor of 100 was found, with detection limit of 0.7 {mu}gL{sup -1}. The percentage of recovery was 98% for As (III) and 95% for As (V) demonstrating the suitability of the procedure.

  3. Determination of arsenic in water samples by Total Reflection X-Ray Fluorescence using pre-concentration with alumina

    Barros, Haydn; Marco Parra, Lue-Meru; Bennun, Leonardo; Greaves, Eduardo D.

    2010-01-01

    The determination of arsenic in water samples requires techniques of high sensitivity. Total Reflection X-Ray Fluorescence (TXRF) allows the determination but a prior separation and pre-concentration procedure is necessary. Alumina is a suitable substrate for the selective separation of the analytes. A method for separation and pre-concentration in alumina, followed by direct analysis of the alumina is evaluated. Quantification was performed using the Al-Kα and Co-Kα lines as internal standard in samples prepared on an alumina matrix, and compared to a calibration with aqueous standards. Artificial water samples of As (III) and As (V) were analyzed after the treatment. Fifty milliliters of the sample at ppb concentration levels were mixed with 10 mg of alumina. The pH, time and temperature were controlled. The alumina was separated from the slurry by centrifugation, washed with de-ionized water and analyzed directly on the sample holder. A pre-concentration factor of 100 was found, with detection limit of 0.7 μgL -1 . The percentage of recovery was 98% for As (III) and 95% for As (V) demonstrating the suitability of the procedure.

  4. X-ray fluorescence analysis of thin films at glancing-incident and -takeoff angles

    Tsuji, K.; Sato, S.; Hirokawa, K.

    1995-01-01

    We have developed a new analytical method, Glancing-Incidence and -Takeoff X-Ray Fluorescence (GIT-XRF) method for the first time. Here, we present an idea for a thin-film analysis and a surface analysis by the GIT-XRF method. In this method, the dependence of the fluorescent x-ray intensity on takeoff angle is measured at various incident angles of the primary x-ray. Compared with a total reflection x-ray fluorescence method, the GIT-XRF method allows a detailed thin-film analysis, because the thin film is cross-checked by many experimental curves. Moreover, a surface-sensitive analysis is also possible by the GIT-XRF method. (author)

  5. New fluorescence spectroscopic method for the simultaneous determination of alkaloids in aqueous extract of green coffee beans.

    Yisak, Hagos; Redi-Abshiro, Mesfin; Chandravanshi, Bhagwan Singh

    2018-05-11

    There is no fluorescence spectroscopic method for the determination of trigonelline and theobromine in green coffee beans. Therefore, the objective of this study was to develop a new fluorescence spectroscopic method to determine the alkaloids simultaneously in the aqueous extract of green coffee beans. The calibration curves were linear in the range 2-6, 1-6, 1-5 mg/L for caffeine, theobromine and trigonelline, respectively, with R 2  ≥ 0.9987. The limit of detection and limit of quantification were 2, 6 and 7 µg/L and 40, 20 and 20 µg/L for caffeine, theobromine and trigonelline, respectively. Caffeine and trigonelline exhibited well separated fluorescence excitation spectra and therefore the two alkaloids were selectively quantified in the aqueous extract of green coffee. While theobromine showed overlapping fluorescence excitation spectra with caffeine and hence theobromine could not be determined in the aqueous extract of green coffee beans. The amount of caffeine and trigonelline in the three samples of green coffee beans were found to be 0.95-1.10 and 1.00-1.10% (w/w), respectively. The relative standard deviations (RSD ≤ 4%) of the method for the three compounds of interest were of very good. The accuracy of the developed analytical method was evaluated by spiking standard caffeine and trigonelline to green coffee beans and the average recoveries were 99 ± 2% for both the alkaloids. A fast, sensitive and reliable fluorescence method for the simultaneous determination of caffeine and trigonelline in the aqueous extract of green coffee beans was developed and validated. The developed method reflected an effective performance to the direct determination of the two alkaloids in the aqueous extract of green coffee beans.

  6. Cell cycle-dependent mobility of Cdc45 determined in vivo by fluorescence correlation spectroscopy.

    Ronan Broderick

    Full Text Available Eukaryotic DNA replication is a dynamic process requiring the co-operation of specific replication proteins. We measured the mobility of eGFP-Cdc45 by Fluorescence Correlation Spectroscopy (FCS in vivo in asynchronous cells and in cells synchronized at the G1/S transition and during S phase. Our data show that eGFP-Cdc45 mobility is faster in G1/S transition compared to S phase suggesting that Cdc45 is part of larger protein complex formed in S phase. Furthermore, the size of complexes containing Cdc45 was estimated in asynchronous, G1/S and S phase-synchronized cells using gel filtration chromatography; these findings complemented the in vivo FCS data. Analysis of the mobility of eGFP-Cdc45 and the size of complexes containing Cdc45 and eGFP-Cdc45 after UVC-mediated DNA damage revealed no significant changes in diffusion rates and complex sizes using FCS and gel filtration chromatography analyses. This suggests that after UV-damage, Cdc45 is still present in a large multi-protein complex and that its mobility within living cells is consistently similar following UVC-mediated DNA damage.

  7. Theoretical study on X-Ray Fluorescence Analysis: Contribution of the self-excitation phenomenon

    RAKOTONDRAJAONA, H.N.J.L.

    1999-01-01

    This work consist in setting up, firstly, fluorescence intensities due to the contribution of secondary and tertiary excitation phenomena which settle among the elements of the same sample during the analysis through X fluorescence, inspired by Sherman calculations. Secondly, we have experimentally checked these expression from the analysis of twelve samples; containing all the following elements: Iron, Copper and Zinc. The difference between the theoretical results and the experimental results has been valued from the formula of the test of χ 2 . We consider that this difference is noticeable compared to other errors due to analysis method. [fr

  8. The determination of iron, chromium, titanium, and tungsten by x-ray-fluorescence spectrometry

    Austen, C.E.

    1977-01-01

    An accurate and precise method is described for the determination of iron and chromium in chromite, iron and titanium in ilmenite, and tungsten in tungsten ores. Samples are prepared for analysis by fusion with sodium peroxide or sodium tetraborate and leaching of the melt in a solution of tartaric or hydrochloric acid. Matrix correction and calibration are achieved by means of the single-standard calibration method with reference solutions prepared from compounds of the elements determined

  9. Highly sensitive enzymatic determination of urea based on the pH-dependence of the fluorescence of graphene quantum dots

    Shao, Taili; Zhang, Ping; Zhuo, Shujuan; Zhu, Changqing; Tang, Lin

    2015-01-01

    We report on a nanoparticle-based fluorescent sensing scheme for urea. It is based on the finding that graphene quantum dots (GQDs) display pH-sensitive green fluorescence if photoexcited at 460 nm. Fluorescence is gradually quenched due to an increase in the local pH value as a result of the hydrolysis of urea as catalyzed by urease. The effect was used to quantify urea in the 0.1–100 mM concentration range, with a limit of detection of 0.01 mM. The method was successfully applied to the determination of urea in human serum samples. The method is simple, effective, and therefore holds promise as a platform for sensing urea in blood. (author)

  10. Fluorescence Determination of Warfarin Using TGA-capped CdTe Quantum Dots in Human Plasma Samples.

    Dehbozorgi, A; Tashkhourian, J; Zare, S

    2015-11-01

    In this study, some effort has been performed to provide low temperature, less time consuming and facile routes for the synthesis of CdTe quantum dots using ultrasound and water soluble capping agent thioglycolic acid. TGA-capped CdTe quantum dots were characterized through x-ray diffraction, transmission electron microscopy, Fourier transform infrared, ultraviolet-visible and fluorescence spectroscopy. The prepared quantum dots were used for warfarin determination based on the quenching of the fluorescence intensity in aqueous solution. Under the optimized conditions, the linear range of quantum dots fluorescence intensity versus the concentration of warfarin was 0.1-160.0 μM, with the correlation coefficient of 0.9996 and a limit of detection of 77.5 nM. There was no interference to coexisting foreign substances. The selectivity of the sensor was also tested and the results show that the developed method possesses a high selectivity for warfarin.

  11. Carbon dots based dual-emission silica nanoparticles as ratiometric fluorescent probe for nitrite determination in food samples.

    Xiang, Guoqiang; Wang, Yule; Zhang, Heng; Fan, Huanhuan; Fan, Lu; He, Lijun; Jiang, Xiuming; Zhao, Wenjie

    2018-09-15

    In this work, a simple and effective strategy for designing a ratiometric fluorescent nanosensor was described. A carbon dots (CDs) based dual-emission nanosensor for nitrite was prepared by coating the CDs on to dye-doped silica nanoparticles. Dual-emission silica nanoparticles fluorescence was quenched in sulfuric acid using potassium bromate (KBrO 3 ). The nitrite present catalyzed the KBrO 3 oxidation, resulting in ratiometric fluorescence response of the dual-emission silica nanoparticles. Several important parameters affecting the performance of the nanosensor were investigated. Under optimized conditions, the limit of detection was 1.0 ng mL -1 and the linear range 10-160 ng mL -1 . Furthermore, the sensor was suitable for nitrite determination in different food samples. Copyright © 2018 Elsevier Ltd. All rights reserved.

  12. Simultaneous determination of 11 fluorescent whitening agents in food-contact paper and board by ion-pairing high-performance liquid chromatography with fluorescence detection.

    Jiang, Dingguo; Chen, Lisong; Fu, Wusheng; Qiu, Hanquan

    2015-02-01

    4,4'-Diaminostilbene-2,2'-disulfonic acid based fluorescent whitening agents (DSD-FWAs) are prohibited in food-contact paper and board in many countries. In this work, a reliable high-performance liquid chromatography method was developed for the simultaneous determination of 11 common DSD-FWAs in paper material. Sample preparation and extraction as well as chromatographic separation of multicomponent DSD-FWAs were successfully optimized. DSD-FWAs in prepared samples were ultrasonically extracted with acetonitrile/water/triethylamine (40:60:1, v/v/v), separated on the C(18) column with the mobile phase containing tetrabutylammonium bromide, and then detected by a fluorescence detector. The limits of detection were 0.12-0.24 mg/kg, and the calibration curves showed the linear correlation (R(2) ≥ 0.9994) within the range of 8.0-100 ng/mL, which was equivalent to the range of 0.80-10 mg/kg in the sample. The average recoveries and the RSDs were 81-106% and 2-9% at two fortification levels (1.0 and 5.0 mg/kg) in paper bowls, respectively. The successful determination of 11 DSD-FWAs in food-contact paper and board obtained from local markets indicated that the newly developed method was rapid, accurate, and highly selective. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Determination of arsenite, arsenate, monomethylarsonic acid and dimethylarsinic acid in cereals by hydride generation atomic fluorescence spectrometry

    Matos Reyes, M.N. [Department of Analytical Chemistry, University of Valencia, 50 Dr. Moliner Street, 46100 Burjassot, Valencia (Spain); Department of Chemistry, Pontificia Universidade Catolica do Rio de Janeiro, Rua Marques de Sao Vicente, 225, 22453-900, Rio de Janeiro, RJ (Brazil); Cervera, M.L. [Department of Analytical Chemistry, University of Valencia, 50 Dr. Moliner Street, 46100 Burjassot, Valencia (Spain)], E-mail: m.luisa.cervera@uv.es; Campos, R.C. [Department of Chemistry, Pontificia Universidade Catolica do Rio de Janeiro, Rua Marques de Sao Vicente, 225, 22453-900, Rio de Janeiro, RJ (Brazil); Guardia, M. de la [Department of Analytical Chemistry, University of Valencia, 50 Dr. Moliner Street, 46100 Burjassot, Valencia (Spain)

    2007-09-15

    A fast, sensitive and simple non-chromatographic analytical method was developed for the speciation analysis of toxic arsenic species in cereal samples, namely rice and wheat semolina. An ultrasound-assisted extraction of the toxic arsenic species was performed with 1 mol L{sup -1} H{sub 3}PO{sub 4} and 0.1% (m/v) Triton XT-114. After extraction, As(III), As(V), dimethylarsinic acid (DMA) and monomethylarsonic acid (MMA) concentrations were determined by hydride generation atomic fluorescence spectrometry using a series of proportional equations corresponding to four different experimental reduction conditions. The detection limits of the method were 1.3, 0.9, 1.5 and 0.6 ng g{sup -1} for As(III), As(V), DMA and MMA, respectively, expressed in terms of sample dry weight. Recoveries were always greater than 90%, and no species interconversion occurred. The speciation analysis of a rice flour reference material certified for total arsenic led to coherent results, which were also in agreement with other speciation studies made on the same certified reference material.

  14. Evaluation of a fluorescent light densitometer for radiochromic film analysis

    Cheung Tsang; Butson, M.J. E-mail: butsonm@iahs.nsw.gov.au; Yu, P.K.N

    2002-01-01

    Radiochromic film dosimetry used in high energy X-ray detection has been evaluated using a VIDAR VXR-12 digitiser for accuracy and results are compared to other densitometers. The VIDAR scanner uses a broad band fluorescent light source which however, produces a negligible ultraviolet reaction effect on the radiochromic film with an estimated equivalent dose of 0.25 cGy darkening per scan to MD-55-2 film. By varying the exposure setting on the scanner, more accurate information can be obtained using radiochromic film within a certain optical density range. Over the range of 0-20 Gy, the scanner can accurately measure dose with a standard deviation of 1.8% calculated between the measured values and a polynomial fit to data. The VIDAR scanner is shown to be a suitable densitometer for radiochromic film.

  15. Evaluation of a fluorescent light densitometer for radiochromic film analysis

    Cheung Tsang; Butson, M.J.; Yu, P.K.N.

    2002-01-01

    Radiochromic film dosimetry used in high energy X-ray detection has been evaluated using a VIDAR VXR-12 digitiser for accuracy and results are compared to other densitometers. The VIDAR scanner uses a broad band fluorescent light source which however, produces a negligible ultraviolet reaction effect on the radiochromic film with an estimated equivalent dose of 0.25 cGy darkening per scan to MD-55-2 film. By varying the exposure setting on the scanner, more accurate information can be obtained using radiochromic film within a certain optical density range. Over the range of 0-20 Gy, the scanner can accurately measure dose with a standard deviation of 1.8% calculated between the measured values and a polynomial fit to data. The VIDAR scanner is shown to be a suitable densitometer for radiochromic film

  16. Fluorescent carbon dots nanosensor for label-free determination of vitamin B12 based on inner filter effect

    Ding, Longhua; Yang, Hongmei; Ge, Shenguang; Yu, Jinghua

    2018-03-01

    A simple and effective fluorescent assay for the determination of vitamin B12 was developed. In this study, carbon dots (CDs) were prepared by one-pot hydrothermal method and directly used as a fluorophore in the inner filter effect (IFE). Both of the maximum absorption peak of vitamin B12 and excitation maxima of CDs are located at 360 nm, hence, the excited light of CDs can be absorbed by vitamin B12, resulting in the fluorescence reduction of CDs. And the fluorescence intensity of CDs decreases with the increasing concentration of vitamin B12. This IFE-based sensing strategy shows a good linear relationship between the normalized fluorescence intensity and the concentration of vitamin B12 ranging from 0 to 60 μM, with a limit of detection (LOD) of 0.1 μM at a signal-to-noise ratio of 3. Furthermore, this proposed approach was successfully applied to vitamin B12 sensing in injections. This IFE sensing platform based on various fluorescent nanomaterials has a high promise for the detection of other biomolecules due to its inherent convenience.

  17. Use of algal fluorescence for determination of phytotoxicity of heavy metals and pesticides as environmental pollutants.

    Samson, G; Popovic, R

    1988-12-01

    The phytotoxicity of heavy metals and pesticides was studied by using the fluorescence induction from the alga Dunaliella tertiolecta. The complementary area calculated from the variable fluorescence induction was used as a direct parameter to estimate phytotoxicity. The value of this parameter was affected when algae were treated with different concentrations of mercury, copper, atrazine, DCMU, Dutox, and Soilgard. The toxic effect of these pollutants was estimated by monitoring the decrease in the complementary area, which reflects photosystem II photochemistry. Further, the authors have demonstrated the advantage of using the complementary area as a parameter of phytotoxicity over using variable fluorescence yield. The complementary area of algal fluorescence can be used as a simple and sensitive parameter in the estimation of the phytotoxicity of polluted water.

  18. Analysis of Septin Reorganization at Cytokinesis Using Polarized Fluorescence Microscopy

    Molly McQuilken

    2017-05-01

    Full Text Available Septins are conserved filament-forming proteins that act in diverse cellular processes. They closely associate with membranes and, in some systems, components of the cytoskeleton. It is not well understood how filaments assemble into higher-order structures in vivo or how they are remodeled throughout the cell cycle. In the budding yeast S. cerevisiae, septins are found through most of the cell cycle in an hourglass organization at the mother-bud neck until cytokinesis when the collar splits into two rings that disassemble prior to the next cell cycle. Experiments using polarized fluorescence microscopy have suggested that septins are arranged in ordered, paired filaments in the hourglass and undergo a coordinated 90° reorientation during splitting at cytokinesis. This apparent reorganization could be due to two orthogonal populations of filaments disassembling and reassembling or being preferentially retained at cytokinesis. In support of this idea, we report a decrease in septin concentration at the mother-bud neck during cytokinesis consistent with other reports and the timing of the decrease depends on known septin regulators including the Gin4 kinase. We took a candidate-based approach to examine what factors control reorientation during splitting and used polarized fluorescence microscopy to screen mutant yeast strains deficient in septin interacting proteins. Using this method, we have linked known septin regulators to different aspects of the assembly, stability, and reorganization of septin assemblies. The data support that ring splitting requires Gin4 activity and an anillin-like protein Bud4, and normal accumulation of septins at the ring requires phosphorylation of Shs1. We found distinct regulatory requirements for septin organization in the hourglass compared to split rings. We propose that septin subpopulations can vary in their localization and assembly/disassembly behavior in a cell-cycle dependent manner at cytokinesis.

  19. Determination of silver in ancient coins by X-ray fluorescence spectrometry

    Pairatana, C.

    1976-01-01

    45 coins of late Ayudhaya and Bangkok periods was analyzed quantitatively by x-ray fluorescence technique using radioisotopic sources Pm - 147/A1 and Am - 241. The fluorescence x-rays were detected by Lithium drifted silicon detector and 1024 channels pulse height analyzer. The procedure was laid a stress on non-destructive methods which could be utilized for analysing various kinds of antiquities and work of arts such as metals, alloys, pottery, ceramics, paper, textile, wood etc

  20. Determination of zinc in ammoniacal ore leaching solutions by X-ray fluorescence spectrometry using a radioactive source

    Cornejo, N.; Afailal, A.; Garcia, F.; Palacios, M.

    1994-01-01

    A method was developed for the fast determination of zinc in leaching solutions by radioisotope energy-dispersive X-ray fluorescence (EDXRF) spectrometry. The measured intensities were used to develop regression models for estimating the zinc concentration. The primary radiation was provided by the 244 Cm radioisotope. Several experimental parameters including the saturation thickness and detection limit were determined. The advantages of the utilization of conditioning agents with elements of low atomic number such as nitric acid were established. (orig.)

  1. Continuous flow hydride generation-atomic fluorescence spectrometric determination and speciation of arsenic in wine

    Karadjova, Irina B. [Faculty of Chemistry, University of Sofia, 1 James Bourchier Blvd., Sofia 1164 (Bulgaria); Lampugnani, Leonardo [C.N.R. Istituto per i processi chimico-fisici, Area della Ricerca di Pisa, Via Moruzzi 1, 56124 Pisa (Italy)]. E-mail: lampugnani@ipcf.cnr.it; Onor, Massimo [C.N.R. Istituto per i processi chimico-fisici, Area della Ricerca di Pisa, Via Moruzzi 1, 56124 Pisa (Italy); D' Ulivo, Alessandro [C.N.R. Istituto per i processi chimico-fisici, Area della Ricerca di Pisa, Via Moruzzi 1, 56124 Pisa (Italy); Tsalev, Dimiter L. [Faculty of Chemistry, University of Sofia, 1 James Bourchier Blvd., Sofia 1164 (Bulgaria)

    2005-07-15

    Methods for the atomic fluorescence spectrometric (AFS) determination of total arsenic and arsenic species in wines based on continuous flow hydride generation (HG) with atomization in miniature diffusion flame (MDF) are described. For hydride-forming arsenic, L-cysteine is used as reagent for pre-reduction and complexation of arsenite, arsenate, monomethylarsonate and dimethylarsinate. Concentrations of hydrochloric acid and tetrahydroborate are optimized in order to minimize interference by ethanol. Procedure permits determination of the sum of these four species in 5-10-fold diluted samples with limit of detection (LOD) 0.3 and 0.6 {mu}g l{sup -1} As in white and red wines, respectively, with precision between 2% and 8% RSD at As levels within 0.5-10 {mu}g l{sup -1}. Selective arsine generation from different reaction media is used for non-chromatographic determination of arsenic species in wines: citrate buffer at pH 5.1 for As(III); 0.2 mol l{sup -1} acetic acid for arsenite + dimethylarsinate (DMA); 8 mol l{sup -1} HCl for total inorganic arsenic [As(III) + As(V)]; and monomethylarsonate (MMA) calculated by difference. Calibration with aqueous and ethanol-matched standard solutions of As(III) is used for 10- and 5-fold diluted samples, respectively. The LODs are 0.4 {mu}g l{sup -1} for As(III) and 0.3 {mu}g l{sup -1} for the other three As species and precision is within 4-8% RSDs. Arsenic species in wine were also determined by coupling of ion chromatographic separation on an anion exchange column and HG-flame AFS detection. Methods were validated by means of recovery studies and comparative analyses by HG-AFS and electrothermal atomic absorption spectrometry after microwave digestion. The LODs were 0.12, 0.27, 0.15 and 0.13 {mu}g l{sup -1} (as As) and RSDs were 2-6%, 5-9%, 3-7% and 2-5% for As(III), As(V), MMA and DMA arsenic species, respectively. Bottled red and white wines from Bulgaria, Republic of Macedonia and Italy were analyzed by non

  2. Continuous flow hydride generation-atomic fluorescence spectrometric determination and speciation of arsenic in wine

    Karadjova, Irina B.; Lampugnani, Leonardo; Onor, Massimo; D'Ulivo, Alessandro; Tsalev, Dimiter L.

    2005-01-01

    Methods for the atomic fluorescence spectrometric (AFS) determination of total arsenic and arsenic species in wines based on continuous flow hydride generation (HG) with atomization in miniature diffusion flame (MDF) are described. For hydride-forming arsenic, L-cysteine is used as reagent for pre-reduction and complexation of arsenite, arsenate, monomethylarsonate and dimethylarsinate. Concentrations of hydrochloric acid and tetrahydroborate are optimized in order to minimize interference by ethanol. Procedure permits determination of the sum of these four species in 5-10-fold diluted samples with limit of detection (LOD) 0.3 and 0.6 μg l -1 As in white and red wines, respectively, with precision between 2% and 8% RSD at As levels within 0.5-10 μg l -1 . Selective arsine generation from different reaction media is used for non-chromatographic determination of arsenic species in wines: citrate buffer at pH 5.1 for As(III); 0.2 mol l -1 acetic acid for arsenite + dimethylarsinate (DMA); 8 mol l -1 HCl for total inorganic arsenic [As(III) + As(V)]; and monomethylarsonate (MMA) calculated by difference. Calibration with aqueous and ethanol-matched standard solutions of As(III) is used for 10- and 5-fold diluted samples, respectively. The LODs are 0.4 μg l -1 for As(III) and 0.3 μg l -1 for the other three As species and precision is within 4-8% RSDs. Arsenic species in wine were also determined by coupling of ion chromatographic separation on an anion exchange column and HG-flame AFS detection. Methods were validated by means of recovery studies and comparative analyses by HG-AFS and electrothermal atomic absorption spectrometry after microwave digestion. The LODs were 0.12, 0.27, 0.15 and 0.13 μg l -1 (as As) and RSDs were 2-6%, 5-9%, 3-7% and 2-5% for As(III), As(V), MMA and DMA arsenic species, respectively. Bottled red and white wines from Bulgaria, Republic of Macedonia and Italy were analyzed by non-chromatographic and chromatographic procedures and the As

  3. Quantitative analysis of dynamic association in live biological fluorescent samples.

    Pekka Ruusuvuori

    Full Text Available Determining vesicle localization and association in live microscopy may be challenging due to non-simultaneous imaging of rapidly moving objects with two excitation channels. Besides errors due to movement of objects, imaging may also introduce shifting between the image channels, and traditional colocalization methods cannot handle such situations. Our approach to quantifying the association between tagged proteins is to use an object-based method where the exact match of object locations is not assumed. Point-pattern matching provides a measure of correspondence between two point-sets under various changes between the sets. Thus, it can be used for robust quantitative analysis of vesicle association between image channels. Results for a large set of synthetic images shows that the novel association method based on point-pattern matching demonstrates robust capability to detect association of closely located vesicles in live cell-microscopy where traditional colocalization methods fail to produce results. In addition, the method outperforms compared Iterated Closest Points registration method. Results for fixed and live experimental data shows the association method to perform comparably to traditional methods in colocalization studies for fixed cells and to perform favorably in association studies for live cells.

  4. X-ray fluorescence analysis of praseodymium oxide/oxalate for rare earth impurities

    Chandola, L.C.; Mohile, A.N.

    1976-01-01

    A method for the determination of lanthanum, cerium, neodymium and samarium oxides in praseodymium oxide is described. The sample in the oxalate form is mixed with boric acid binder in the weight ratio of 1:1 and pressed into a pellet. The pellet is irradiated by X-rays from a tungsten tube and fluorescent X-rays are dispersed by a LiF (200) crystal in a Philips semiautomatic X-ray fluorescence spectrometer. The intensity of the characteristic X-rays of the impurity elements is measured by a flow proportional counter at selected 20 angles. The minium determination limit is 0.01% for all impurities. (author)

  5. X-ray fluorescence analysis of bimetallic complexes on the basis of tantalocene trihydride

    Shurupova, T.I.; Sokolova, T.A.

    1989-01-01

    Methods of X-ray fluorescence determination of metals in tantalocene trihydride complexes of Cp 2 TaH 3 ·nMeHalm composition where Me=Cu, Mg, Hal=Cl, I, n=1 or 2, m=1 or 2 are developed. To obtain the form, stable in relation to the air oxygen and water vapours, the complexes were burut off up to metal oxides. Possibility of direct X-ray fluorescent determination is tested taking the most stable iodide copper-containing complex as an example

  6. Improving the spectral analysis of Fluorescence Resonance Energy Transfer in live cells: application to interferon receptors and Janus kinases.

    Krause, Christopher D; Digioia, Gina; Izotova, Lara S; Pestka, Sidney

    2013-10-01

    The observed Fluorescence Resonance Energy Transfer (FRET) between fluorescently labeled proteins varies in cells. To understand how this variation affects our interpretation of how proteins interact in cells, we developed a protocol that mathematically separates donor-independent and donor-dependent excitations of acceptor, determines the electromagnetic interaction of donors and acceptors, and quantifies the efficiency of the interaction of donors and acceptors. By analyzing large populations of cells, we found that misbalanced or insufficient expression of acceptor or donor as well as their inefficient or reversible interaction influenced FRET efficiency in vivo. Use of red-shifted donors and acceptors gave spectra with less endogenous fluorescence but produced lower FRET efficiency, possibly caused by reduced quenching of red-shifted fluorophores in cells. Additionally, cryptic interactions between jellyfish FPs artefactually increased the apparent FRET efficiency. Our protocol can distinguish specific and nonspecific protein interactions even within highly constrained environments as plasma membranes. Overall, accurate FRET estimations in cells or within complex environments can be obtained by a combination of proper data analysis, study of sufficient numbers of cells, and use of properly empirically developed fluorescent proteins. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Portable and Disposable Paper-Based Fluorescent Sensor for In Situ Gaseous Hydrogen Sulfide Determination in Near Real-Time.

    Petruci, João Flávio da Silveira; Cardoso, Arnaldo Alves

    2016-12-06

    Hydrogen sulfide is found in many environments including sewage systems, petroleum extraction platforms, kraft paper mills, and exhaled breath, but its determination at ppb levels remains a challenge within the analytical chemistry field. Off-line methods for analysis of gaseous reduced sulfur compounds can suffer from a variety of biases associated with high reactivity, sorptive losses, and atmospheric oxidative reactions. Here, we present a portable, online, and disposable gas sensor platform for the in situ determination of gaseous hydrogen sulfide, employing a 470 nm light emitting diode (LED) and a microfiber optic USB spectrometer. A sensing layer was created by impregnating 2.5 μL (0.285 nmol) of fluorescein mercury acetate (FMA) onto the surface of a micropaper analytical device with dimensions of 5 × 5 mm, which was then positioned in the optical detection system. The quantitative determination of H 2 S was based on the quenching of fluorescence intensity after direct selective reaction between the gas and FMA. This approach enabled linear calibration within the range 17-67 ppb of H 2 S, with a limit of detection of 3 ppb. The response time of the sensor was within 60 s, and the repeatability was 6.5% (RSD). The sensor was employed to monitor H 2 S released from a mini-scale wastewater treatment tank in a research laboratory. The appropriate integration of optoelectronic and mechanical devices, including LED, photodiode, pumps, and electronic boards, can be used to produce simple, fully automated portable sensors for the in situ determination of H 2 S in a variety of environments.

  8. [Improvement of the method for methylmercury determination in aquatic products using liquid chromatography online coupled with atomic fluorescence spectrometry].

    Shang, Xiaohong; Zhao, Yunfeng; Zhang, Lei; Li, Xiaowei; Wu, Yongning

    2011-07-01

    The improvement method was developed for methylmercury determination using liquid chromatography online coupled with cold vapor atomic fluorescence spectrometry (LC-CV-AFS). Cysteine was used as complexing agent in mobile phase instead of mercaptoethanol. Under the optimized conditions, baseline separation of mercury species could be achieved within 8 min on a C18 column with a mobile phase of 5% (v/v) acetonitrile-1 g/L L-cysteine-50 mmol/L ammonium acetate aqueous solution. The linear range of calibration curve of methylmercury was 1-50 microg/L and the limit of detection (S/N = 3) for methylmercury was 0.3 microg/L. Ultrasonication assisted hydrochloric acid extraction was used to extract methylmercury from seafood samples. The sample extract was cleaned up by a C18 solid phase extraction (SPE) cartridge. For validation of the method, certified reference materials and spiked seafood samples were analyzed. The determined methylmercury contents of certified reference materials NIST1566b, BCR464 and GBW10029 agreed well with the certified values. The determined methylmercury values for Food Analysis Performance Assessment Scheme (FAPAS) sample 07115 were satisfied. The recoveries of methylmercury in seafood samples at three spiked levels (10, 50 and 500 microg/kg) ranged from 89% to 112%, including cooked seafood food. The precision of the method based on relative standard deviation (RSD) was not more than 7%. The present method of LC-CV-AFS is accurate, sensitive, simple, and can meet the demand of methylmercury determination in seafood.

  9. Photon induced x-ray fluorescence analysis using energy dispersive detector and dichotomous sampler

    Jaklevic, J.M.; Loo, B.W.; Goulding, F.S.

    1976-01-01

    Operating experience in using the photon-excited energy-dispersive x-ray fluorescence analysis system has demonstrated the applicability of this technique to large-scale air-sampling networks. This experience has shown that it is possible to perform automatic sampling and analysis of aerosol particulates at a sensitivity and accuracy more than adequate for most air pollution studies

  10. TRACE ANALYSIS BY LASER-EXCITED ATOMIC FLUORESCENCE WITH ATOMIZATION IN A PULSED PLASMA

    Lunyov , O.; Oshemkov , S.; Petrov , A.

    1991-01-01

    The possibilities of plasma atomization for laser fluorescence trace analysis are discussed. Pulsed hot hollow cathode discharge was used for analysis of solutions and powdered samples. The high voltage spark and laser-induced breakdown (laser spark) were used as atomizers of metal-containing atmospheric aerosols. Detection limits were improved by means of temporal background selection.

  11. Abstracts of the 8th Conference on total reflection x-ray fluorescence analysis and related methods

    Wobrauschek, P.

    2000-01-01

    The 8. conference on total reflection x-ray fluorescence analysis and related methods held from 25.9 to 29.9.2000 contains 79 abstracts about x-ray fluorescence analysis (XRFA) as a powerful tool used for industrial production, geological prospecting and for environmental control. Total reflection x-ray fluorescence spectroscopy is also a tool used for chemical analysis in medicine, industry and research. (E.B.)

  12. LED-FISH: Fluorescence microscopy based on light emitting diodes for the molecular analysis of Her-2/neu oncogene amplification

    Vollmer Ekkehard

    2008-12-01

    Full Text Available Abstract Light emitting diodes (LED, which are available as small monochromatic light sources with characteristic features such as maximum illumination power combined with minimum energy consumption and extremely long lifespan have already proved as a highly potential low-cost alternative for specific diagnostic applications in clinical medicine such as tuberculosis fluorescence microscopy. Likewise, the most reliable evaluation of Her-2/neu (c-erbB2 gene amplification, which has been established in the last few years for routine diagnosis in clinical pathology as determinant towards Herceptin-based treatment of patients with breast cancer, is based on fluorescence in situ hybridization (FISH and corresponding high priced fluorescence equipment. In order to test the possibility to utilize the advantages of low-cost LED technology on FISH analysis of c-erbB2 gene expression for routine diagnostic purposes, the applicability of a standard bright field Carl Zeiss Axiostar Plus microscope equipped with a Fraen AFTER* LED Fluorescence Microscope Kit for the detection of Her-2/neu gene signals was compared to an advanced Nikon Eclipse 80i fluorescence microscope in combination with a conventional 100W mercury vapor lamp. Both microscopes were fitted with the same Quicam FAST CCD digital camera to unequivocally compare the quality of the captured images. C-erbB2 gene expression was analyzed in 30 different human tissue samples of primary invasive breast cancer, following formalin fixation and subsequent paraffin-embedding. The Her2/neu gene signals (green were identifiable in the tumor cells in all cases and images of equal quality were captured under almost identical conditions by 480 nm (blue LED module equipped standard Axiostar microscope as compared to conventional fluorescence microscopy. In this first attempt, these monochromatic LED elements proved in principle to be suitable for the detection of Her-2/neu gene expression by FISH. Thus, our own

  13. Major and minor elements analysis in soil samples by neutron activation analysis and X-ray fluorescence

    Morcelli, Claudia Petronilho Ribeiro; Ana Maria Graciano; Enzweiler, Jacinta

    2002-01-01

    In the present work, Instrumental Neutron Activation Analysis (INAA) and X-Ray Fluorescence were employed to analyze major and minor elements in soil samples collected near Bandeirantes road. Elements of environmental interest, such as Al, Sb, As, Ba, Cd, Pb, Co, Cu, Cr, Fe, Mn, Mo, Ni, Se, V and Zn, which have reference background levels, were determined. The samples were dried in an oven at 40 deg C, were sieved (<2 mm), grinded and were analyzed by INAA and FRX. The aims of this work were: to evaluate the possible variations in the concentration levels in soil due to emission of particulate from vehicles and other anthropogenic sources; to compare the results obtained by using both techniques. This preliminary study showed that the concentration levels of the elements of environmental interest agree with reference values for tropical soils in the sampling sites, except for Ba, which presented higher values. (author)

  14. The analysis of anode sludges by x-ray-fluorescence spectrometry

    Austen, C.E.; Wall, G.J.

    1978-01-01

    A method is described for the analysis, by X-ray-fluorescence spectrometry, of anode sludges for the determination of antimony, bismuth, copper, iron, lead, nickel, selenium, silver, tellurium, tin, and zinc. The preparation of the samples involves fusion with a flux of barium peroxide and lithium hydroxide, and with dichromium trioxide as the internal standard, in a zirconium or vitreous-carbon crucible and casting of the melt in an aluminium mould; the fused disc so formed is then pulverized and briquetted to form pellets. Calibration curves, which are straight lines for all the elemets determined because the flux contains a heavy absorber, are established by measurement of pellets prepared from standard anode sludges, pure metals, compounds of the metals, or any combination of these materials. The precision of the results varies between 2 and 15 per cent relative standard deviation, depending on the concentration of the element being determined. The accuracy of the results is comparable with that obtained by wet-chemical methods. The laboratory method is given in an appendix

  15. X-ray fluorescence analysis of strontium in environmental water by using barium carbonate coprecipitation method

    Nishioka, Hiroshi; Yoneda, Akio; Maeda, Yoshimichi; Azumi, Takatugu

    1986-01-01

    Determination of strontium in environmental water was studied by a coprecipitation method with barium carbonate and the subsequent X-ray fluorescence analysis. Fifty mg of barium ion and 1 g of sodium carbonate were added to sample water, which was then mixed for one hour by a magnetic stirrer. Precipitate was gathered onto a membrane filter paper to measure its XF intensity. The amount of strontium from 2 to 150 μg could be repeatedly determined by means of the calibration curve method, and the limit of detection was found to be 0.6 μg of strontium. A large amount of calcium and magnesium ions was found to interfere with the coprecipitation of strontium ion. However, this interference could be eliminated by using a small amount of sample water. Strontium in several environmental waters was determined by the above method. The results obtained from the calibration curve method and the standard addition method agreed with each other, and also agreed with those from the atomic absorption spectrometry. (author)

  16. Facilitating in vivo tumor localization by principal component analysis based on dynamic fluorescence molecular imaging

    Gao, Yang; Chen, Maomao; Wu, Junyu; Zhou, Yuan; Cai, Chuangjian; Wang, Daliang; Luo, Jianwen

    2017-09-01

    Fluorescence molecular imaging has been used to target tumors in mice with xenograft tumors. However, tumor imaging is largely distorted by the aggregation of fluorescent probes in the liver. A principal component analysis (PCA)-based strategy was applied on the in vivo dynamic fluorescence imaging results of three mice with xenograft tumors to facilitate tumor imaging, with the help of a tumor-specific fluorescent probe. Tumor-relevant features were extracted from the original images by PCA and represented by the principal component (PC) maps. The second principal component (PC2) map represented the tumor-related features, and the first principal component (PC1) map retained the original pharmacokinetic profiles, especially of the liver. The distribution patterns of the PC2 map of the tumor-bearing mice were in good agreement with the actual tumor location. The tumor-to-liver ratio and contrast-to-noise ratio were significantly higher on the PC2 map than on the original images, thus distinguishing the tumor from its nearby fluorescence noise of liver. The results suggest that the PC2 map could serve as a bioimaging marker to facilitate in vivo tumor localization, and dynamic fluorescence molecular imaging with PCA could be a valuable tool for future studies of in vivo tumor metabolism and progression.

  17. Computed microtomography and X-ray fluorescence analysis for comprehensive analysis of structural changes in bone.

    Buzmakov, Alexey; Chukalina, Marina; Nikolaev, Dmitry; Schaefer, Gerald; Gulimova, Victoria; Saveliev, Sergey; Tereschenko, Elena; Seregin, Alexey; Senin, Roman; Prun, Victor; Zolotov, Denis; Asadchikov, Victor

    2013-01-01

    This paper presents the results of a comprehensive analysis of structural changes in the caudal vertebrae of Turner's thick-toed geckos by computer microtomography and X-ray fluorescence analysis. We present algorithms used for the reconstruction of tomographic images which allow to work with high noise level projections that represent typical conditions dictated by the nature of the samples. Reptiles, due to their ruggedness, small size, belonging to the amniote and a number of other valuable features, are an attractive model object for long-orbital experiments on unmanned spacecraft. Issues of possible changes in their bone tissue under the influence of spaceflight are the subject of discussions between biologists from different laboratories around the world.

  18. A portable UV-fluorescence multispectral imaging system for the analysis of painted surfaces

    Comelli, Daniela; Valentini, Gianluca; Nevin, Austin; Farina, Andrea; Toniolo, Lucia; Cubeddu, Rinaldo

    2008-08-01

    A portable fluorescence multispectral imaging system was developed and has been used for the analysis of artistic surfaces. The imaging apparatus exploits two UV lamps for fluorescence excitation and a liquid crystal tunable filter coupled to a low-noise charge coupled device as the image detector. The main features of the system are critically presented, outlining the assets, drawbacks, and practical considerations of portability. A multivariate statistical treatment of spectral data is further considered. Finally, the in situ analysis with the new apparatus of recently restored Renaissance wall paintings is presented.

  19. Determination of catecholamine in human serum by a fluorescent quenching method based on a water-soluble fluorescent conjugated polymer-enzyme hybrid system.

    Huang, Hui; Gao, Yuan; Shi, Fanping; Wang, Guannan; Shah, Syed Mazhar; Su, Xingguang

    2012-03-21

    In this paper, a sensitive water-soluble fluorescent conjugated polymer biosensor for catecholamine (dopamine DA, adrenaline AD and norepinephrine NE) was developed. In the presence of horse radish peroxidase (HRP) and H(2)O(2), catecholamine could be oxidized and the oxidation product of catecholamine could quench the photoluminescence (PL) intensity of poly(2,5-bis(3-sulfonatopropoxy)-1,4-phenylethynylenealt-1,4-poly(phenylene ethynylene)) (PPESO(3)). The quenching PL intensity of PPESO(3) (I(0)/I) was proportional to the concentration of DA, AD and NE in the concentration ranges of 5.0 × 10(-7) to 1.4 × 10(-4), 5.0 × 10(-6) to 5.0 × 10(-4), and 5.0 × 10(-6) to 5.0 × 10(-4) mol L(-1), respectively. The detection limit for DA, AD and NE was 1.4 × 10(-7) mol L(-1), 1.0 × 10(-6) and 1.0 × 10(-6) mol L(-1), respectively. The PPESO(3)-enzyme hybrid system based on the fluorescence quenching method was successfully applied for the determination of catecholamine in human serum samples with good accuracy and satisfactory recovery. The results were in good agreement with those provided by the HPLC-MS method.

  20. Automating X-ray Fluorescence Analysis for Rapid Astrobiology Surveys.

    Thompson, David R; Flannery, David T; Lanka, Ravi; Allwood, Abigail C; Bue, Brian D; Clark, Benton C; Elam, W Timothy; Estlin, Tara A; Hodyss, Robert P; Hurowitz, Joel A; Liu, Yang; Wade, Lawrence A

    2015-11-01

    A new generation of planetary rover instruments, such as PIXL (Planetary Instrument for X-ray Lithochemistry) and SHERLOC (Scanning Habitable Environments with Raman Luminescence for Organics and Chemicals) selected for the Mars 2020 mission rover payload, aim to map mineralogical and elemental composition in situ at microscopic scales. These instruments will produce large spectral cubes with thousands of channels acquired over thousands of spatial locations, a large potential science yield limited mainly by the time required to acquire a measurement after placement. A secondary bottleneck also faces mission planners after downlink; analysts must interpret the complex data products quickly to inform tactical planning for the next command cycle. This study demonstrates operational approaches to overcome these bottlenecks by specialized early-stage science data processing. Onboard, simple real-time systems can perform a basic compositional assessment, recognizing specific features of interest and optimizing sensor integration time to characterize anomalies. On the ground, statistically motivated visualization can make raw uncalibrated data products more interpretable for tactical decision making. Techniques such as manifold dimensionality reduction can help operators comprehend large databases at a glance, identifying trends and anomalies in data. These onboard and ground-side analyses can complement a quantitative interpretation. We evaluate system performance for the case study of PIXL, an X-ray fluorescence spectrometer. Experiments on three representative samples demonstrate improved methods for onboard and ground-side automation and illustrate new astrobiological science capabilities unavailable in previous planetary instruments. Dimensionality reduction-Planetary science-Visualization.

  1. Quantitative determination on heavy metals in different stages of wine production by Total Reflection X-ray Fluorescence and Energy Dispersive X-ray Fluorescence: Comparison on two vineyards

    Pessanha, Sofia [Centro Fisica Atomica, Departamento de Fisica, Faculdade de Ciencias, Universidade de Lisboa, Av. Prof. Gama Pinto, 2, 1649-003 Lisboa (Portugal); Carvalho, Maria Luisa, E-mail: luisa@cii.fc.ul.p [Centro Fisica Atomica, Departamento de Fisica, Faculdade de Ciencias, Universidade de Lisboa, Av. Prof. Gama Pinto, 2, 1649-003 Lisboa (Portugal); Becker, Maria; Bohlen, Alex von [Institute for analytical Sciences, Bunsen-Kirchhoff-Str. 11, 44139 Dortmund (Germany)

    2010-06-15

    The purpose of this study is to determine the elemental content, namely heavy metals, of samples of vine-leaves, grapes must and wine. In order to assess the influence of the vineyard age on the elemental content throughout the several stages of wine production, elemental determinations of trace elements were made on products obtained from two vineyards aged 6 and 14 years from Douro region. The elemental content of vine-leaves and grapes was determined by Energy Dispersive X-Ray Fluorescence (EDXRF), while analysis of the must and wine was performed by Total Reflection X-ray Fluorescence (TXRF). Almost all elements present in wine and must samples did not exceed the recommended values found in literature for wine. Bromine was present in the 6 years old wine in a concentration 1 order of magnitude greater than what is usually detected. The Cu content in vine-leaves from the older vineyard was found to be extremely high probably due to excessive use of Cu-based fungicides to control vine downy mildew. Higher Cu content was also detected in grapes although not so pronounced. Concerning the wine a slightly higher level was detected on the older vineyard, even so not exceeding the recommended value.

  2. Quantitative determination on heavy metals in different stages of wine production by Total Reflection X-ray Fluorescence and Energy Dispersive X-ray Fluorescence: Comparison on two vineyards

    Pessanha, Sofia; Carvalho, Maria Luisa; Becker, Maria; Bohlen, Alex von

    2010-01-01

    The purpose of this study is to determine the elemental content, namely heavy metals, of samples of vine-leaves, grapes must and wine. In order to assess the influence of the vineyard age on the elemental content throughout the several stages of wine production, elemental determinations of trace elements were made on products obtained from two vineyards aged 6 and 14 years from Douro region. The elemental content of vine-leaves and grapes was determined by Energy Dispersive X-Ray Fluorescence (EDXRF), while analysis of the must and wine was performed by Total Reflection X-ray Fluorescence (TXRF). Almost all elements present in wine and must samples did not exceed the recommended values found in literature for wine. Bromine was present in the 6 years old wine in a concentration 1 order of magnitude greater than what is usually detected. The Cu content in vine-leaves from the older vineyard was found to be extremely high probably due to excessive use of Cu-based fungicides to control vine downy mildew. Higher Cu content was also detected in grapes although not so pronounced. Concerning the wine a slightly higher level was detected on the older vineyard, even so not exceeding the recommended value.

  3. ROCKS & MINERALS DETERMINATION AND ANALYSIS

    2015-01-01

    20150204 Abaydulla Alimjan(Department of Chemistry and Environmental Sciences,Kashgar Teachers College,Kashgar 844006,China);Cheng Chunying Non-Metallic Element Composition Analysis of Non-Ferrous Metal Ores from Oytagh Town,Xinjiang(Rock and Mineral Analysis,ISSN0254-5357,CN11-2131/TD,33(1),2014,p.44-50,5illus.,4tables,28refs.)Key words:nonferrous metals ore,nonmetals,chemical analysis,thermogravimetric analysis Anions in non-ferrous ore materials

  4. Determination of air pollutants by nuclear chemical analysis

    Lesny, J.; Toelgyessy, J.

    1975-01-01

    Nuclear analytical methods are discussed with a view to their applicability in the determination of air pollutants. It is shown that some methods (use of radioactive kryptonates in automatic analyzers, application of activation analysis, X-ray fluorescence methods) are developed in theory and proven in practice in such an extent to be widely used in the near future in the control of the environment. Many other methods are becoming increasingly important for the solution of specific problems of environmental protection (such as the control of sudden environmental contamination in the proximity of chemical plants and industrial centers). (author)

  5. Solution conformation of 2-aminopurine dinucleotide determined by ultraviolet two-dimensional fluorescence spectroscopy

    Widom, Julia R; Marcus, Andrew H; Johnson, Neil P; Von Hippel, Peter H

    2013-01-01

    We have observed the conformation-dependent electronic coupling between the monomeric subunits of a dinucleotide of 2-aminopurine (2-AP), a fluorescent analogue of the nucleic acid base adenine. This was accomplished by extending two-dimensional fluorescence spectroscopy (2D FS)—a fluorescence-detected variation of 2D electronic spectroscopy—to excite molecular transitions in the ultraviolet (UV) regime. A collinear sequence of four ultrafast laser pulses centered at 323 nm was used to resonantly excite the coupled transitions of 2-AP dinucleotide. The phases of the optical pulses were continuously swept at kilohertz frequencies, and the ensuing nonlinear fluorescence was phase-synchronously detected at 370 nm. Upon optimization of a point–dipole coupling model to our data, we found that in aqueous buffer the 2-AP dinucleotide adopts an average conformation in which the purine bases are non-helically stacked (center-to-center distance R 12 = 3.5 ± 0.5 Å , twist angle θ 12 = 5° ± 5° ), which differs from the conformation of such adjacent bases in duplex DNA. These experiments establish UV–2D FS as a method for examining the local conformations of an adjacent pair of fluorescent nucleotides substituted into specific DNA or RNA constructs, which will serve as a powerful probe to interpret, in structural terms, biologically significant local conformational changes within the nucleic acid framework of protein–nucleic acid complexes. (paper)

  6. Multilayers quantitative X-ray fluorescence analysis applied to easel paintings.

    de Viguerie, Laurence; Sole, V Armando; Walter, Philippe

    2009-12-01

    X-ray fluorescence spectrometry (XRF) allows a rapid and simple determination of the elemental composition of a material. As a non-destructive tool, it has been extensively used for analysis in art and archaeology since the early 1970s. Whereas it is commonly used for qualitative analysis, recent efforts have been made to develop quantitative treatment even with portable systems. However, the interpretation of the results obtained with this technique can turn out to be problematic in the case of layered structures such as easel paintings. The use of differential X-ray attenuation enables modelling of the various layers: indeed, the absorption of X-rays through different layers will result in modification of intensity ratio between the different characteristic lines. This work focuses on the possibility to use XRF with the fundamental parameters method to reconstruct the composition and thickness of the layers. This method was tested on several multilayers standards and gives a maximum error of 15% for thicknesses and errors of 10% for concentrations. On a painting test sample that was rather inhomogeneous, the XRF analysis provides an average value. This method was applied in situ to estimate the thickness of the layers a painting from Marco d'Oggiono, pupil of Leonardo da Vinci.

  7. Determination of trace element levels in leaves of Nerium oleander using X-Ray Fluorescence

    Santos, Ramon S.; Sanches, Francis A.C.R.A.; Neves, Arthur O.P.; Oliveira, Luis F.; Oliveira, Davi F.; Anjos, Marcelino J.

    2013-01-01

    The environmental pollution by human activity has been one of the most concerns in the last years, principally due to rapid urban growth in the cities and the industrialization process. The air pollution can be increased due to several different kinds of emissions: urban traffic, industrial activities, burning fuel, civil industry of construction/demolition, fires and natural phenomena. Many of these emissions move from long distances due to convections currents and finally tend to deposit mainly in the plants leaves and in the soil. Thus, the plants leaves works as a natural sampler by the emissions deposit in these ones. In this study Nerium oleander leaves were used to measure the environmental pollutions levels in different sampling urban regions in the city of Rio de Janeiro/RJ: Andarai, Benfica, Bonsucesso, Caju, Engenho de Dentro, Engenho Novo, Estacio, Grajau, Inhauma, Lins, Maracana, Maria da Graca, Meier, Praca da Bandeira, Riachuelo, Rio Comprido, Sao Cristovao, Tijuca, Vila Isabel and city Center. The control samples were collected in Campo Grande near of Parque Nacional da Pedra Branca/RJ (National Park of Pedra Branca/RJ). The leaves were collected from adult plants and after the collection the samples were cleaned and placed in the greenhouse for drying, then were mashed and pressed into tablets forms. The analyses were performed using the energy dispersion X-ray fluorescence (EDXRF), developed on the own laboratory and based in a SiPIN detector and a mini X ray tube. It was possible to detect 16 elements in the analyzed samples: K, Ca, Cr, Mn, Fe, Cu, Zn, Br, Rb, Sr, Ba and Pb. The results shows that, in the studied areas, the analysis of the Nerium oleander plant shows a low-cost option and with a substantial efficiency as an environmental pollution biomonitor. (author)

  8. Mass-produced lonophore-based fluorescent microspheres for trace level determination of lead ions.

    Telting-Diaz, Martin; Bakker, Eric

    2002-10-15

    The development and characterization of small, uniform, and mass-produced plasticized PVC-based sensing microspheres in view of rapid trace level analysis of lead ions is reported. Micrometer-sized particles obtained via an automated casting process were rendered selective for lead ions by doping them with highly selective components in a manner analogous to traditional optode sensing films. Single particles that contained the lipophilic ionophore N,N,N',N'-tetradodecyl-3-6-dioxaoctane-1-thio-8-oxodiamide (ETH 5493), the chromoionophore ETH 5418 together with a lipophilized indocarbocyanine derivative as internal reference dye (DiIC18), and lipophilic ion-exchanger sites sodium tetrakis[3,5-bistrifluoromethylphenyl]borate, yielded measurable lead responses at the low nanomolar level in pH buffered solutions. The detection limit for single particles was 3 x 10(-9) M at pH 5.7. The microspheres were fabricated via a reproducible formation of polymer droplets within a flowing aqueous phase followed by collection of spherical particles of approximately 13 microm in size. The particles were immobilized and assayed individually in a microflow cell via fluorescence microscopy. Selectivity patterns found were in agreement with those reported earlier for the lead-selective ligand ETH 5493, and all response functions were fully described by theory. In contrast to optode films that necessitated very long equilibration times and large sample volumes in diluted samples of analyte, particles exhibited extremely enhanced equilibrium response times. Thus, for lead sample concentrations at and above 5 x 10(-8) M, response times were approximately 3 min, whereas at the detection limit, complete equilibrium was recorded after just 15 min, with required sample volumes on the order of 1 mL This new class of microspheres appears to be suitable for rapid and sensitive ion detection at trace levels in environmental and biological applications.

  9. Determination of trace element levels in leaves of Nerium oleander using X-Ray Fluorescence

    Santos, Ramon S.; Sanches, Francis A.C.R.A.; Neves, Arthur O.P.; Oliveira, Luis F.; Oliveira, Davi F.; Anjos, Marcelino J. [Universidade do Estado do Rio de Janeiro (UERJ), Rio de Janeiro, RJ (Brazil). Inst. de Fisica Armando Dias Tavares. Dept. de Fisica Aplicada e Termodinamica

    2013-07-01

    The environmental pollution by human activity has been one of the most concerns in the last years, principally due to rapid urban growth in the cities and the industrialization process. The air pollution can be increased due to several different kinds of emissions: urban traffic, industrial activities, burning fuel, civil industry of construction/demolition, fires and natural phenomena. Many of these emissions move from long distances due to convections currents and finally tend to deposit mainly in the plants leaves and in the soil. Thus, the plants leaves works as a natural sampler by the emissions deposit in these ones. In this study Nerium oleander leaves were used to measure the environmental pollutions levels in different sampling urban regions in the city of Rio de Janeiro/RJ: Andarai, Benfica, Bonsucesso, Caju, Engenho de Dentro, Engenho Novo, Estacio, Grajau, Inhauma, Lins, Maracana, Maria da Graca, Meier, Praca da Bandeira, Riachuelo, Rio Comprido, Sao Cristovao, Tijuca, Vila Isabel and city Center. The control samples were collected in Campo Grande near of Parque Nacional da Pedra Branca/RJ (National Park of Pedra Branca/RJ). The leaves were collected from adult plants and after the collection the samples were cleaned and placed in the greenhouse for drying, then were mashed and pressed into tablets forms. The analyses were performed using the energy dispersion X-ray fluorescence (EDXRF), developed on the own laboratory and based in a SiPIN detector and a mini X ray tube. It was possible to detect 16 elements in the analyzed samples: K, Ca, Cr, Mn, Fe, Cu, Zn, Br, Rb, Sr, Ba and Pb. The results shows that, in the studied areas, the analysis of the Nerium oleander plant shows a low-cost option and with a substantial efficiency as an environmental pollution biomonitor. (author)

  10. Simultaneous determination of sulpiride and mebeverine by HPLC method using fluorescence detection: application to real human plasma

    Walash Mohamed I

    2012-02-01

    Full Text Available Abstract A new simple, rapid and sensitive reversed-phase liquid chromatographic method was developed and validated for the simultaneous determination of sulpiride (SUL and mebeverine Hydrochloride (MEB in the presence of their impurities and degradation products. The separation of these compounds was achieved within 6 min on a 250 mm, 4.6 mm i.d., 5 m particle size Waters®-C18 column using isocractic mobile phase containing a mixture of acetonitrile and 0.01 M dihydrogenphosphate buffer (45:55 at pH = 4.0. The analysis was performed at a flow rate of 1.0 mL/min with fluorescence-detection at excitation 300 nm and emission at 365 nm. The concentration-response relationship was linear over a concentration range of 10- 100 ng/mL for both MEB and SUL with a limit of detection 0.73 ng/mL and 0.85 ng/mL for MEB and SUL respectively. The proposed method was successfully applied for the analysis of both MEB and SUL in bulk with average recoveries of 100.22 ± 0.757% and 99.96 ± 0.625% respectively, and in commercial tablets with average recoveries of 100.04 ± 0.93% and 100.03 ± 0.376% for MEB and SUL respectively. The proposed method was successfully applied to the determination of MEB metabolite (veratic acid in real plasma simultaneously with SUL. The mean% recoveries (n = 3 for both MEB metabolite (veratic acid and SUL were 100.36 ± 2.92 and 99.06 ± 2.11 for spiked human plasma respectively. For real human plasma, the mean% recoveries (n = 3 were and respectively.

  11. Rapid Analysis and Exploration of Fluorescence Microscopy Images

    Pavie, Benjamin; Rajaram, Satwik; Ouyang, Austin; Altschuler, Jason; Steininger, Robert J; Wu, Lani; Altschuler, Steven

    2014-01-01

    Despite rapid advances in high-throughput microscopy, quantitative image-based assays still pose significant challenges. While a variety of specialized image analysis tools are available, most traditional image-analysis-based workflows have steep learning curves (for fine tuning of analysis parameters) and result in long turnaround times between imaging and analysis. In particular, cell segmentation, the process of identifying individual cells in an image, is a major bottleneck in this regard.

  12. Determination of trace zinc in seawater by coupling solid phase extraction and fluorescence detection in the Lab-On-Valve format.

    Grand, Maxime M; Chocholouš, Petr; Růžička, Jarda; Solich, Petr; Measures, Christopher I

    2016-06-07

    By virtue of their compactness, long-term stability, minimal reagent consumption and robustness, miniaturized sequential injection instruments are well suited for automation of assays onboard research ships. However, in order to reach the sensitivity and limit of detection required for open-ocean determinations of trace elements, it is necessary to preconcentrate the analyte prior its derivatization and subsequent detection by fluorescence. In this work, a novel method for the determination of dissolved zinc (Zn) at subnanomolar levels in seawater is described. The proposed method combines, for the first time, automated matrix removal, extraction of the target element, and fluorescence detection within a miniaturized flow manifold, based on the Lab-On-Valve (LOV) concept. The key feature of the microfluidic manipulation of the sample is flow programming, designed to pass sample through a mini-column where the target analyte and other complexable cations are retained, while the seawater matrix is washed out. Next, zinc is eluted and merged with a Zn selective fluorescent probe (FluoZin-3) at the confluence point of the LOV central channel using two high-precision stepper motor driven pumps that are operated in concert. Finally, the thus formed Zn complex is transported to the LOV flow cell for selective fluorescence measurement. This work describes the characterization and optimization of the method including Solid Phase Extraction using the Toyopearl AF-Chelate-650M resin, and detailed assay protocol controlled by a commercially available software and instrument. The proposed method features a LOD of 0.02 nM, high precision (seawater reference standards and comparison with ICP-MS determinations on seawater samples collected in the upper 1300 m of the subtropical south Indian Ocean. This work confirms that integration of sample pretreatment with optical detection in the LOV format offers a widely applicable approach to trace analysis of seawater. Copyright © 2016

  13. Recent results of synchrotron radiation induced total reflection X-ray fluorescence analysis at HASYLAB, beamline L

    Streli, C. [Atominstitut, Vienna University of Technology, Stadionallee 2, A-1020 Vienna (Austria)]. E-mail: streli@ati.ac.at; Pepponi, G. [ITC-irst, Povo (Italy); Wobrauschek, P. [Atominstitut, Vienna University of Technology, Stadionallee 2, A-1020 Vienna (Austria); Jokubonis, C. [Atominstitut, Vienna University of Technology, Stadionallee 2, A-1020 Vienna (Austria); Falkenberg, G. [Hamburger Synchrotronstrahlungslabor at Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, D-22603 Hamburg (Germany); Zaray, G. [Institute of Inorganic and Applied Chemistry, 3 EOTVOS Univ, Budapest (Hungary); Broekaert, J. [Institute of Anorganic and Applied Chemistry, University Hamburg, Martin-Luther-King-Platz 6, 20146 Hamburg (Germany); Fittschen, U. [Institute of Anorganic and Applied Chemistry, University Hamburg, Martin-Luther-King-Platz 6, 20146 Hamburg (Germany); Peschel, B. [Institute of Anorganic and Applied Chemistry, University Hamburg, Martin-Luther-King-Platz 6, 20146 Hamburg (Germany)

    2006-11-15

    At the Hamburger Synchrotronstrahlungslabor (HASYLAB), Beamline L, a vacuum chamber for synchrotron radiation-induced total reflection X-ray fluorescence analysis, is now available which can easily be installed using the adjustment components for microanalysis present at this beamline. The detector is now in the final version of a Vortex silicon drift detector with 50-mm{sup 2} active area from Radiant Detector Technologies. With the Ni/C multilayer monochromator set to 17 keV extrapolated detection limits of 8 fg were obtained using the 50-mm{sup 2} silicon drift detector with 1000 s live time on a sample containing 100 pg of Ni. Various applications are presented, especially of samples which are available in very small amounts: As synchrotron radiation-induced total reflection X-ray fluorescence analysis is much more sensitive than tube-excited total reflection X-ray fluorescence analysis, the sampling time of aerosol samples can be diminished, resulting in a more precise time resolution of atmospheric events. Aerosols, directly sampled on Si reflectors in an impactor were investigated. A further application was the determination of contamination elements in a slurry of high-purity Al{sub 2}O{sub 3}. No digestion is required; the sample is pipetted and dried before analysis. A comparison with laboratory total reflection X-ray fluorescence analysis showed the higher sensitivity of synchrotron radiation-induced total reflection X-ray fluorescence analysis, more contamination elements could be detected. Using the Si-111 crystal monochromator also available at beamline L, XANES measurements to determine the chemical state were performed. This is only possible with lower sensitivity as the flux transmitted by the crystal monochromator is about a factor of 100 lower than that transmitted by the multilayer monochromator. Preliminary results of X-ray absorption near-edge structure measurements for As in xylem sap from cucumber plants fed with As(III) and As(V) are

  14. Recent results of synchrotron radiation induced total reflection X-ray fluorescence analysis at HASYLAB, beamline L

    Streli, C.; Pepponi, G.; Wobrauschek, P.; Jokubonis, C.; Falkenberg, G.; Zaray, G.; Broekaert, J.; Fittschen, U.; Peschel, B.

    2006-01-01

    At the Hamburger Synchrotronstrahlungslabor (HASYLAB), Beamline L, a vacuum chamber for synchrotron radiation-induced total reflection X-ray fluorescence analysis, is now available which can easily be installed using the adjustment components for microanalysis present at this beamline. The detector is now in the final version of a Vortex silicon drift detector with 50-mm 2 active area from Radiant Detector Technologies. With the Ni/C multilayer monochromator set to 17 keV extrapolated detection limits of 8 fg were obtained using the 50-mm 2 silicon drift detector with 1000 s live time on a sample containing 100 pg of Ni. Various applications are presented, especially of samples which are available in very small amounts: As synchrotron radiation-induced total reflection X-ray fluorescence analysis is much more sensitive than tube-excited total reflection X-ray fluorescence analysis, the sampling time of aerosol samples can be diminished, resulting in a more precise time resolution of atmospheric events. Aerosols, directly sampled on Si reflectors in an impactor were investigated. A further application was the determination of contamination elements in a slurry of high-purity Al 2 O 3 . No digestion is required; the sample is pipetted and dried before analysis. A comparison with laboratory total reflection X-ray fluorescence analysis showed the higher sensitivity of synchrotron radiation-induced total reflection X-ray fluorescence analysis, more contamination elements could be detected. Using the Si-111 crystal monochromator also available at beamline L, XANES measurements to determine the chemical state were performed. This is only possible with lower sensitivity as the flux transmitted by the crystal monochromator is about a factor of 100 lower than that transmitted by the multilayer monochromator. Preliminary results of X-ray absorption near-edge structure measurements for As in xylem sap from cucumber plants fed with As(III) and As(V) are reported. Detection

  15. Improved sample treatment for the determination of insoluble soap in sewage sludge samples by liquid chromatography with fluorescence detection.

    Cantarero, Samuel; Zafra-Gómez, A; Ballesteros, O; Navalón, A; Vílchez, J L; Crovetto, G; Verge, C; de Ferrer, J A

    2010-09-15

    A new selective and sensitive method for the determination of insoluble fatty acid salts (soap) in sewage sludge samples is proposed. The method involves a clean up of sample with petroleum ether, the conversion of calcium and magnesium insoluble salts into soluble potassium salts, potassium salts extraction with methanol, and a derivatization procedure previous to the liquid chromatography with fluorescence detection (LC-FLD) analysis. Three different extraction techniques (Soxhlet, microwave-assisted extraction and ultrasounds) were compared and microwave-assisted extraction (MAE) was selected as appropriate for our purpose. This allowed to reduce the extraction time and solvent waste (50 mL of methanol in contrast with 250 mL for Soxhlet procedure). The absence of matrix effect was demonstrated with two standards (C(13:0) and C(17:0)) that are not commercials and neither of them has been detected in sewage sludge samples. Therefore, it was possible to evaluate the matrix effect since both standards have similar environmental behaviour (adsorption and precipitation) to commercial soaps (C(10:0)-C(18:0)). The method was successfully applied to samples from different sources and consequently, with different composition. Copyright (c) 2010 Elsevier B.V. All rights reserved.

  16. Determination of Ochratoxin A in Wheat and Maize by Solid Bar Microextraction with Liquid Chromatography and Fluorescence Detection

    Nabil Al-Hadithi

    2015-08-01

    Full Text Available Solid bar microextraction (SBME, followed by liquid chromatography with fluorescence detection (HPLC-FLD, for the quantification of ochratoxin A in wheat and maize was developed. Ground wheat and maize grains were extracted with acetonitrile-water-acetic acid (79:20:1, v/v/v, followed by defatting with cyclohexane, and subjected to SBME-LC-FLD analysis. SBME devices were constructed by packing 2 mg sorbent (C18 into porous polypropylene micro-tubes (2.5 cm length, 600 μm i.d., and 0.2 μm pore size. SBME devices were conditioned with methanol and placed into 5 mL stirred sample solutions for 70 min. After extraction, OTA was desorbed into 200 μL of methanol for 15 min, the solution was removed in vacuum, the residue was dissolved in 50 μL of methanol-water (1:1, v/v and ochratoxin A content was determined by HPLC-FLD. Under optimized extraction conditions, the limit of detection of 0.9 μg·kg−1 and 2.5 μg·kg−1 and the precision of 3.4% and 5.0% over a concentration range of 1 to 100 μg·kg−1 in wheat and maize flour, respectively, were obtained.

  17. Evaluation of a hydride generation-atomic fluorescence system for the determination of arsenic using a dielectric barrier discharge atomizer

    Zhu Zhenli; Liu Jixin; Zhang Sichun; Na Xing; Zhang Xinrong

    2008-01-01

    A new atomizer based on atmospheric pressure dielectric barrier discharge (DBD) plasma was specially designed for atomic fluorescence spectrometry (AFS) in order to be applied to the measurement of arsenic. The characteristics of the DBD atomizer and the effects of different parameters (power, discharge gas, gas flow rate, and KBH 4 concentration) were discussed in the paper. The DBD atomizer shows the following features: (1) low operation temperature (between 44 and 70 deg. C, depending on the operation conditions); (2) low power consumption; (3) operation at atmospheric pressure. The detection limit of As(III) using hydride generation (HG) with the proposed DBD-AFS was 0.04 μg L -1 . The analytical results obtained by the present method for total arsenic in reference materials, orchard leaves (SRM 1571) and water samples GBW(E) 080390, agree well with the certified values. The present HG-DBD-AFS is more sensitive and reliable for the determination of arsenic. It is a very promising technique allowing for field arsenic analysis based on atomic spectrometry

  18. Optimization of a polarized source for in vivo x-ray fluorescence analysis of platinum and other heavy metals

    Lewis, D.G.

    1994-01-01

    The Monte Carlo method was used to optimize a polarized photon source for the x-ray fluorescence analysis of platinum and other heavy metals in vivo. The source consisted of a 140 kVp, 25 mA x-ray tube with the photons plane-polarized by 90 o scattering. The use of plane-polarized photons results in a significant reduction in background when the fluorescent radiation is measured along the direction of polarization. A Monte Carlo computer programme was written to simulate the production and interaction of polarized photons in order to determine the optimal polarizing material and dimensions, together with beam width and geometrical arrangement of source, polarizer and beam collimators. Calculated photon energy distributions are compared with experimental data to test the validity of the model. (author)

  19. Sensitive determination of enoxacin in pharmaceutical formulations by its quench effect on the fluorescence of glutathione-capped CdTe quantum dots.

    Yang, Qiong; Tan, Xuanping; Yang, Jidong

    2016-02-01

    A sensitive and simple method for the determination of enoxacin (ENX) was developed based on the fluorescence quenching effect of ENX for glutathione (GSH)-capped CdTe quantum dots (QDs). Under optimum conditions, a good linear relationship was obtained from 4.333 × 10(-9)  mol⋅L(-1) to 1.4 × 10(-5)  mol⋅L(-1) with a correlation coefficient (R) of 0.9987, and the detection limit (3σ/K) was 1.313 × 10(-9)  mol⋅L(-1). The corresponding mechanism has been proposed on the basis of electron transfer supported by ultraviolet-visible (UV) light absorption, fluorescence spectroscopy, and the measurement of fluorescence lifetime. The method has been applied to the determination of ENX in pharmaceutical formulations (enoxacin gluconate injections and commercial tablets) with satisfactory results. The proposed method manifested several advantages such as high sensitivity, short analysis time, low cost and ease of operation. Copyright © 2015 John Wiley & Sons, Ltd.

  20. Ultratrace determination of lead in whole blood using electrothermal atomization laser-excited atomic fluorescence spectrometry.

    Wagner, E P; Smith, B W; Winefordner, J D

    1996-09-15

    Laser-excited atomic fluorescence has been used to detect lead that was electrothermally atomized from whole blood in a graphite furnace. A 9 kHz repetition rate copper vapor laser pumped dye laser was used to excite the lead at 283.3 nm, and the resulting atomic fluorescence was detected at 405.8 nm. No matrix modification was used other than a 1:21 dilution of the whole blood with high-purity water. Using the atomic fluorescence peak area as the analytical measure and a background correction technique based upon a simultaneous measurement of the transmitted laser intensity, excellent agreement for NIST and CDC certified whole blood reference samples was obtained with aqueous standards. A limit of detection in blood of 10 fg/mL (100 ag absolute) was achieved.