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Sample records for preparative thin-layer chromatography

  1. A validated high performance thin layer chromatography method for determination of yohimbine hydrochloride in pharmaceutical preparations.

    Science.gov (United States)

    Badr, Jihan M

    2013-01-01

    Yohimbine is an indole alkaloid used as a promising therapy for erectile dysfunction. A number of methods were reported for the analysis of yohimbine in the bark or in pharmaceutical preparations. In the present work, a simple and sensitive high performance thin layer chromatographic method is developed for determination of yohimbine (occurring as yohimbine hydrochloride) in pharmaceutical preparations and validated according to International Conference of Harmonization (ICH) guidelines. The method employed thin layer chromatography aluminum sheets precoated with silica gel as the stationary phase and the mobile phase consisted of chloroform:methanol:ammonia (97:3:0.2), which gave compact bands of yohimbine hydrochloride. Linear regression data for the calibration curves of standard yohimbine hydrochloride showed a good linear relationship over a concentration range of 80-1000 ng/spot with respect to the area and correlation coefficient (R(2)) was 0.9965. The method was evaluated regarding accuracy, precision, selectivity, and robustness. Limits of detection and quantitation were recorded as 5 and 40 ng/spot, respectively. The proposed method efficiently separated yohimbine hydrochloride from other components even in complex mixture containing powdered plants. The amount of yohimbine hydrochloride ranged from 2.3 to 5.2 mg/tablet or capsule in preparations containing the pure alkaloid, while it varied from zero (0) to 1.5-1.8 mg/capsule in dietary supplements containing powdered yohimbe bark. We concluded that this method employing high performance thin layer chromatography (HPTLC) in quantitative determination of yohimbine hydrochloride in pharmaceutical preparations is efficient, simple, accurate, and validated.

  2. A validated high performance thin layer chromatography method for determination of yohimbine hydrochloride in pharmaceutical preparations

    OpenAIRE

    Jihan M Badr

    2013-01-01

    Background: Yohimbine is an indole alkaloid used as a promising therapy for erectile dysfunction. A number of methods were reported for the analysis of yohimbine in the bark or in pharmaceutical preparations. Materials and Method: In the present work, a simple and sensitive high performance thin layer chromatographic method is developed for determination of yohimbine (occurring as yohimbine hydrochloride) in pharmaceutical preparations and validated according to International Conference of Ha...

  3. In situ Silver Spot Preparation and on-Plate Surface-Enhanced Raman Scattering Detection in Thin Layer Chromatography Separation

    Science.gov (United States)

    Herman, K.; Mircescu, N. E.; Szabo, L.; Leopold, L. F.; Chiş, V.; Leopold, N.

    2013-05-01

    An improved approach for surface-enhanced Raman scattering (SERS) detection of mixture constituents after thin layer chromatography (TLC) separation is presented. A SERS active silver substrate was prepared under open air conditions, directly on the thin silica film by photo-reduction of silver nitrate, allowing the detection of binary mixtures of cresyl violet, bixine, crystal violet, and Cu(II) complex of 4-(2-pyridylazo)resorcinol. The recorded SERS spectrum provides a unique spectral fingerprint for each molecule; therefore the use of analyte standards is avoided, thus rendering the presented procedure advantageous compared to the conventional detection methodology in TLC.

  4. Identification and determination of oxytetracycline, tiamulin, lincomycin, and spectinomycin in veterinary preparations by thin-layer chromatography/densitometry.

    Science.gov (United States)

    Krzek, J; Kwiecień, A; Starek, M; Kierszniewska, A; Rzeszutko, W

    2000-01-01

    A thin-layer chromatographic/densitometric method was developed for the identification and quantitation of oxytetracycline, tiamulin, lincomycin, and spectinomycin in veterinary preparations. Silica gel-coated thin layer chromatography plates and 2 mobile phases were used to separate these constituents. The appropriate compositions of the suitable mobile phases were established: 10% citric acid solution-n-hexane-ethanol (80 + 1 + 1, v/v) and n-butanol-ethanol-chloroform-25% ammonia (4 + 5 + 2 + 5, v/v). Along with Rf values and spot colors, direct UV and visual densitometric measurements were used for identification. Similar measuring ranges were used for quantitative analysis to obtain repeatable and reliable results for the preparations examined. The results of the quantitative analysis are characterized by a small confidence interval and are close to the declared contents of active constituents: oxytetracycline 30.01 +/- 0.38 g at lambda = 350 nm and 30.24 +/- 0.86 g at lambda = 430 nm; tiamulin, 10.19 +/- 0.86 g at lambda = 450 nm; lincomycin, 2.27 +/- 0.08 g at lambda = 278 nm; and spectinomycin, 2.18 +/- 0.07 g at lambda = 421 nm. The recoveries for all antibiotics ranged from 100.01 to 102.54%.

  5. Radioactive preparations. Determination of radiochemical purity by thin-layer chromatography

    International Nuclear Information System (INIS)

    1986-01-01

    The standard sets the data which must be attached to every sample, and the equipment, chemicals and auxiliary substances used in the determination of radiochemical purity of substances by chromatography. Described are preparation of the sample, the procedure of sample deposition, the development, drying and detection of the radioactive preparation. The qualitative and quantitative assessment of the radiochromatogram is described as are the calculation of radiochemical purity and the determination of the reproducibility of measurement of radiochemical purity of radioactive preparations. (E.S.)

  6. Profiling the triacylglyceride contents in bat integumentary lipids by preparative thin layer chromatography and MALDI-TOF mass spectrometry.

    Science.gov (United States)

    Pannkuk, Evan L; Risch, Thomas S; Savary, Brett J

    2013-09-05

    The mammalian integument includes sebaceous glands that secrete an oily material onto the skin surface. Sebum production is part of the innate immune system that is protective against pathogenic microbes. Abnormal sebum production and chemical composition are also a clinical symptom of specific skin diseases. Sebum contains a complex mixture of lipids, including triacylglycerides, which is species-specific. The broad chemical properties exhibited by diverse lipid classes hinder the specific determination of sebum composition. Analytical techniques for lipids typically require chemical derivatizations that are labor-intensive and increase sample preparation costs. This paper describes how to extract lipids from mammalian integument, separate broad lipid classes by thin-layer chromatography, and profile the triacylglyceride contents using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. This robust method enables a direct determination of the triacylglyceride profiles among species and individuals, and it can be readily applied to any taxonomic group of mammals.

  7. Solvent Front Position Extraction procedure with thin-layer chromatography as a mode of multicomponent sample preparation for quantitative analysis by instrumental technique.

    Science.gov (United States)

    Klimek-Turek, A; Sikora, E; Dzido, T H

    2017-12-29

    A concept of using thin-layer chromatography to multicomponent sample preparation for quantitative determination of solutes followed by instrumental technique is presented. Thin-layer chromatography (TLC) is used to separate chosen substances and their internal standard from other components (matrix) and to form a single spot/zone containing them at the solvent front position. The location of the analytes and internal standard in the solvent front zone allows their easy extraction followed by quantitation by HPLC. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Ultra-thin layer chromatography and surface enhanced Raman spectroscopy on silver nanorod array substrates prepared by oblique angle deposition

    Science.gov (United States)

    Chen, Jing; Abell, Justin; Huang, Yao-wen; Zhao, Yiping

    2012-06-01

    We demonstrate the potential use of silver nanorod (AgNR) array substrates for on-chip separation and detection of chemical mixtures by ultra-thin layer chromatography (UTLC) and surface enhanced Raman spectroscopy (SERS). The capability of the AgNR substrates to separate different compounds in a mixture was explored using a mixture of the food colorant Brilliant Blue FCF and lactic acid, and the mixtures of Methylene Violet and BSA at various concentrations. After the UTLC process, spatially-resolved SERS spectra were collected along the mobile phase development direction and the intensities of specific SERS peaks from each component were used to generate chromatograms. The AgNR substrates demonstrate the capability of separating Brilliant Blue from lactic acid, as well as revealing the SERS signal of Methylene Violet from the massive BSA background after a simple UTLC step. This technique may have significant practical implications in actual detection of small molecules from complex food or clinical backgrounds.

  9. Thin-layer and paper chromatography

    International Nuclear Information System (INIS)

    Sherma, J.

    1986-01-01

    This selective review covers the literature of thin-layer chromatography (TLC) and paper chromatography (PC) cited in Chemical Abstracts from December 5, 1983, through November 25, 1985, and Analytical Abstracts from November 1983 to November 1985. Also researched directly were the following important journals publishing papers on TLC and PC: the Journal of Chromatography (including its bibliography issues), Journal of High Resolution Chromatography and Chromatography Communications, Journal of Chromatographic Science, Chromatographia, Analytical Chemistry, JAOAC, and the special TLC issues of the Journal of Liquid Chromatography. Many of the inherent advantages of TLC that are obvious to workers familiar with high performance, quantitative theory and practice still are not appreciated adequately by the majority of people using chromatography. These include unrestricted access to the separation process; introducing magnetic, thermal, electrical, and other physical forces to improve resolution; high sample throughput; truly multidimensional separations; and the use of controlled multiple gradients. Many advantages of TLC relative to column chromatography were discussed in the Introductions to our 1982 and 1984 reviews of TLC in this Journal. No complete commercial robotics system specifically for TLC has been developed, but all necessary modules are available for such a system. The combination of robotics, with the continued development of theory, practice, and instrumentation will lead eventually to TLC systems that are unrivaled for speed, versatility, accuracy, precision, and sensitivity. 573 references

  10. Thin-Layer and Paper Chromatography.

    Science.gov (United States)

    Sherma, Joseph; Fried, Bernard

    1984-01-01

    Reviews literature on chromatography examining: books, reviews, student experiments; chromatographic systems, techniques, apparatus; detecting and identification of separated zones; preparative chromatography and radiochromatography; and applications related to specific materials (such as acids, alcohols, amino acids, antibiotics, enzymes, dyes,…

  11. Loading Effects on Resolution in Thin Layer Chromatography and ...

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 10; Issue 11. Loading Effects on Resolution in Thin Layer Chromatography and Paper Chromatography. K Girigowda V H Mulimani. Classroom Volume 10 Issue 11 November 2005 pp 79-84 ...

  12. Application of thin-layer chromatography in radiochemistry

    International Nuclear Information System (INIS)

    Maki, Yasuyuki; Murakami, Yukio.

    1976-01-01

    In relation to the experimental procedures of thin-layer chromatography (TLC) in radiochemistry, the authors explained the preparation and development of radioactive test solutions, the methods of detection by autoradiography of isolated spots and by the calculation of measuring apparatus, and the identification of isolated spots. Next they outlined the carrier-free isolation and purification of nuclides, the quantification in combination with γ-ray spectrum, confirmation of the purity of RI-labeled medical supplies, their application to RI generator, thin-layer electrophoresis, in which electrophoresis and TLC were combined, and the application of this electrophoresis to isolation in recoil chemistry and to analysis and identification in carrier-free chemistry. (Kanao, K.)

  13. Pre-staining thin layer chromatography method for amino acid ...

    African Journals Online (AJOL)

    Jane

    2010-12-13

    Dec 13, 2010 ... inexpensive and the results obtained were clean and reproducible. However, it is suitable for the high throughput screening of amino acid-producing strains. Key words: Thin layer chromatography, pre-staining, amino acid detection. INTRODUCTION. Several analytical techniques have been often used for.

  14. Robotic thin layer chromatography instrument for synthetic chemistry

    International Nuclear Information System (INIS)

    Corkan, L.A.; Haynes, E.; Kline, S.; Lindsey, J.S.

    1991-01-01

    We have constructed a second generation instrument for performing automated thin layer chromatography (TLC), The TLC instrument Consists of four dedicated stations for (1) plate dispensing, (2) sample application, (3) plate development, and (4) densitometry. A robot is used to move TLC plates among stations. The TLC instrument functions either as a stand-alone unit or as one analytical module in a robotic workstation for synthetic chemistry. An integrated hardware and software architecture enables automatic TLC analysis of samples produced concurrently from synthetic reactions in progress on the workstation. The combination of fixed automation and robotics gives a throughput of 12 TLC samples per hour. From these results a blueprint has emerged for an advanced automated TLC instrument with far greater throughput and analytical capabilities

  15. High performance thin layer chromatography profile of Cassytha filiformis

    Institute of Scientific and Technical Information of China (English)

    Mythili Sathiavelu; Sathiavelu Arunachalam

    2012-01-01

    Objective: To study the phenols, flavonoids, saponin profile of the medicinal plant Cassytha filiformis (C. filiformis) using high performance thin layer chromatography (HPTLC). Methods:The extracts were tested to determine the presence of various phytochmeicals like alkaloids, phenolic compounds, flavonoids, carbohydrates, glycosides, saponins, terpenoids, tannins, fixed oils, fats and protein and aminoacids (Harborne and Harborne, 1998). HPTLC studies were carried out by Harborne and Wagner et al method. Different compositions of the mobile phase for HPTLC analysis were tested in order to obtain high resolution and reproducible peaks. Results: The results of the preliminary phytochemical studies confirm the presence of phenols, alkaloids, carbohydrates, saponins, flavanoids, terpenoids and tannins in the methanolic extracts of C. filiformis. The methanolic extracts of C. filiformis displayed the presence of 13 types of phenolic substances with 13 different Rf values ranging from 0.01 to 0.96. The results illustrated the presence of 9 different types of flavonoides with 9 different Rf values ranging from 0.01 to 0.97. The results of HPTLC analysis of saponins demonstrated the presence of 11 different types of saponins with 11 different Rf values ranging from 0.04 to 0.92. Conclusions: In the present study we observed the phenols, flavonoids, saponin profile of the medicinal plant C. filiformis using high performance thin layer chromatography (HPTLC). Hence it was concluded that the phenolic compounds present in the methonolic extract could be responsible for antioxidant activities. Plant derived antioxidants, especially phenols and flavonoids, have been described to have various properties like anticancer, antiaging and prevention of cardiovascular diseases. Furthur, separation and characterization of the bioactive compound from the plant is to be evaluated and reported in near future.

  16. Thin-layer chromatography and colorimetric analysis of multi-component explosive mixtures

    Science.gov (United States)

    Pagoria, Philip F.; Mitchell, Alexander R.; Whipple, Richard E.; Carman, M. Leslie

    2014-08-26

    A thin-layer chromatography method for detection and identification of common military and peroxide explosives in samples includes the steps of provide a reverse-phase thin-layer chromatography plate; prepare the plate by marking spots on which to deposit the samples by touching the plate with a marker; spot one micro liter of a first standard onto one of the spots, spot one micro liter of a second standard onto another of the spots, and spot samples onto other of spots producing a spotted plate; add eluent to a developing chamber; add the spotted plate to the developing chamber; remove the spotted plate from the developing chamber producing a developed plate; place the developed plate in an ultraviolet light box; add a visualization agent to a dip tank; dip the developed plate in the dip tank and remove the developed plate quickly; and detect explosives by viewing said developed plate.

  17. Phytochemical analysis of ethanolic extract of Dichrostachys Cinerea W and Arn leaves by a thin layer chromatography, high performance thin layer chromatography and column chromatography

    OpenAIRE

    M Vijayalakshmi; K Periyanayagam; K Kavitha; K Akilandeshwari

    2013-01-01

    Background: The leaves of Dichrostachys cinerea are used as laxative, diuretic, painkiller. It is also used in the treatment of gonorrhoea, boils, oedema, gout, veneral diseases and nasopharyngeal affections, etc. Materials and Methods: The Phytochemical investigation of ethanolic extract of D. cinerea leaves were performed by standard chemical tests, thin layer chromatography (TLC) by using various solvent systems, and by high performance liquid chromatography (HPTLC). Two compounds were...

  18. Normal and Reversed-Phase Thin Layer Chromatography of Green Leaf Extracts

    Science.gov (United States)

    Sjursnes, Birte Johanne; Kvittingen, Lise; Schmid, Rudolf

    2015-01-01

    Introductory experiments of chromatography are often conducted by separating colored samples, such as inks, dyes, and plant extracts, using filter paper, chalk, or thin layer chromatography (TLC) plates with various solvent systems. Many simple experiments have been reported. The relationship between normal chromatography and reversed-phase…

  19. Thin-layer chromatography - liquid chromatography, an ideal supplement demonstrated by the separation of lanthanoids

    International Nuclear Information System (INIS)

    Specker, H.; Hufnagel, A.

    1984-01-01

    All lanthanoids have been separated by thin-layer chromatography (TLC) with short retention times by using a mixture of ether/tetrahydrofurane (THF)/bis-(2-ethylhexyl)-phosphate (HDEHP)/nitric acid. The eluent was empirically tested by synergistic effects. The results have been transferred to high-performance liquid chromatography /HPLC). It was possible to use the same eluent in TLC and HPLC both for the analytical separation of all lanthanoids and for the separation of fission products. The experimental experience gained in HPLC could be applied to the pre-concentration of isotopes in TLC. Both methods excellently supplemented each other in the separation of lanthanoids. (orig.) [de

  20. Thin-layer chromatography of radioactively labelled cholesterol and precursors from biological material

    International Nuclear Information System (INIS)

    Pill, J.; Aufenanger, J.; Stegmeier, K.; Schmidt, F.H.; Mueller, D.; Boehringer Mannheim G.m.b.H.

    1987-01-01

    The investigation methods of the action of xenobiotics on sterol biosynthesis from 14 C-acetate in rat hepatocyte cultures can be developed, with regard to extraction using Extrelut and the separation of the sterol pattern by thin-layer chromatography, in such a way that they are suitable for wider application, e.g., screening. Good visualisation and recognition of changes in the sterol pattern are possible using autoradiography of the thin-layer chromatogram. (orig.)

  1. Thin-layer chromatography can resolve phosphotyrosine, phosphoserine, and phosphothreonine in a protein hydrolyzate

    International Nuclear Information System (INIS)

    Neufeld, E.; Goren, H.J.; Boland, D.

    1989-01-01

    A solution of propionic acid, 1 M ammonium hydroxide, and isopropyl alcohol (45/17.5/17.5, v/v) was the ascending solvent in the separation of phosphotyrosine, phosphothreonine, and phosphoserine by thin-layer chromatography. The immobile phase was cellulose. The relative migrations were 0.44, 0.38, and 0.2, respectively. A previously described thin-layer system consisting of isobutyric acid and 0.5 M ammonium hydroxide (50/30, v/v) gave very similar relative migrations. To determine the usefulness of thin-layer chromatography in phosphoamino acid analysis, the propionic acid/ammonium hydroxide/isopropyl alcohol solution was used to characterize phosphorylated residues in a plasma membrane protein which is a substrate for the insulin receptor kinase, in insulin receptor phosphorylated histone H2B, and in an in vivo phosphorylated 90000-Da protein from IM9 cells. 32 P-labeled proteins were separated by dodecyl sulfate-gel electrophoresis, digested with trypsin, and then hydrolyzed with 6 N HCl, 2 h, 110 degrees C. Following thin-layer chromatography of the hydrolyzates and autoradiography, phosphotyrosine was detected in insulin receptor substrates, and phosphoserine and phosphothreonine were found in the in vivo-phosphorylated protein. This study supports previous reports about the practicality of thin-layer chromatography in phosphoamino acid analysis and it demonstrates that a propionic acid, ammonium hydroxide, isoprophyl alcohol solution may be a useful ascending solvent mixture for this purpose

  2. Combining surface enhanced Raman scattering (SERS) and high-performance thin-layer chromatography (HPTLC)

    Science.gov (United States)

    Koglin, E.

    A new method for preparing SERS active surfaces using silver colloidal spheres deposited on HPTLC plates, used for thin-layer chromatography, is discussed in detail. The sensitivity of these activated HPTLC plates is so high that in-situ vibrational investigations of chromatogram spots are possible at the nanogram level. The HPTLC/SERS spectra of purine, benzoic acid and 1-nitro-pyrene adsorbed on silver colloidal activated silica gel plates are measured in the nanogram region. In addition we also report in this paper on the results of a feasibility study performed to evaluate the analytical potential of micro-Raman spectroscopy (triple monochromator, multichannel detection system) in SERS/HPTLC spot characterization. It permits the acquisition of Raman spectra from HPTLC spots down to 1 μm in size or other forms of microsamples approaching the picogram level in mass.

  3. Interaction between cholesterol and non-ionic surfactants studied by thin-layer chromatography

    Czech Academy of Sciences Publication Activity Database

    Forgács, E.; Cserháti, T.; Farkas, O.; Eckhardt, Adam; Mikšík, Ivan; Deyl, Zdeněk

    2004-01-01

    Roč. 27, č. 13 (2004), s. 1981-1992 ISSN 1082-6076 Grant - others:CZ-HU(CZ) Cooperation program Institutional research plan: CEZ:AV0Z5011922 Keywords : cholesterol * non-ionic surfactant * thin - layer chromatography Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 0.836, year: 2004

  4. Sensitive Thin-Layer Chromatography Detection of Boronic Acids Using Alizarin

    NARCIS (Netherlands)

    Duval, F.L.; Beek, van T.A.; Zuilhof, H.

    2012-01-01

    A new method for the selective and sensitive detection of boronic acids on thin-layer chromatography plates is described. The plate is briefly dipped in an alizarin solution, allowed to dry in ambient air, and observed under 366 nm light. Alizarin emits a bright yellow fluorescence only in the

  5. Thin-Layer Chromatography/Desorption Atmospheric Pressure Photoionization Orbitrap Mass Spectrometry of Lipids

    Czech Academy of Sciences Publication Activity Database

    Rejšek, Jan; Vrkoslav, Vladimír; Vaikkinen, A.; Haapala, M.; Kauppila, T. J.; Kostiainen, R.; Cvačka, Josef

    2016-01-01

    Roč. 88, č. 24 (2016), s. 12279-12286 ISSN 0003-2700 R&D Projects: GA ČR GAP206/12/0750 Institutional support: RVO:61388963 Keywords : desorption atmospheric pressure photoionization * thin-layer chromatography * lipids Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 6.320, year: 2016

  6. Phospholipids, Dietary Supplements, and Chicken Eggs: An Inquiry-Based Exercise Using Thin-Layer Chromatography

    Science.gov (United States)

    Potteiger, Sara E.; Belanger, Julie M.

    2015-01-01

    This inquiry-based experiment is designed for organic or biochemistry undergraduate students to deduce the identity of phospholipids extracted from chicken eggs and dietary supplements. This is achieved using thin-layer chromatography (TLC) data, a series of guided questions of increasing complexity, and provided relative retention factor (Rf)…

  7. Possible artefacts in thin layer chromatography of tritium-labelled hydrocortisone

    International Nuclear Information System (INIS)

    Sofronie, E.

    1982-12-01

    Artefacts appearing in thin layer chromatography of tritium labelled hydrocortisone are reported. Evidences are presented that these artefacts cause misleading results concerning radiocheemical purity determiniation. Finally, it is reported a rapid and efficient chromatographic technique allowing the elimination of these artefacts and obtaining of an accurate value for radiochemical purity. (author)

  8. Bibliography of paper and thin-layer chromatography 1970-1973 and survey of applications

    International Nuclear Information System (INIS)

    Macek, K.; Hais, I.M.; Kopecky, J.; Schwarz, V.; Gasparic, J.; Churacek, J.

    1976-01-01

    The present volume covers developments in both paper and thin-layer chromatography from 1970 to the middle of 1973 and is a continuation of the previous four volumes, published in 1960, 1962, 1968 and 1972. An author index is given

  9. Peak broadening in paper chromatography and related techniques : III. Peak broadening in thin-layer chromatography on cellulose powder

    NARCIS (Netherlands)

    Ligny, C.L. de; Remijnse, A.G.

    1968-01-01

    The mechanism of peak broadening in thin-layer chromatography on cellulose powder was investigated by comparing the peak widths obtained in chromatography with those caused only by diffusion in the cellulose powder, for a set of amino acids of widely differing RF values and six kinds of cellulose

  10. Use of low volatility mobile phases in electroosmotic thin-layer chromatography.

    Science.gov (United States)

    Berezkin, V G; Balushkin, A O; Tyaglov, B V; Litvin, E F

    2005-08-19

    A variant of electroosmotic thin-layer chromatography is suggested with the use of low volatility compounds as mobile phases aimed at drastically decreasing the evaporation of the mobile phase and improving the reproducibility of the method. The linear movement velocity of zones of separated compounds is experimentally shown to increase 2-12-fold in electroosmotic chromatography (compared to similar values in traditional TLC). The separation efficiency is also considerably increased.

  11. Thin-layer chromatography of polyphosphoinositides from platelet extracts: interference by an unknown phospholipid

    International Nuclear Information System (INIS)

    Tysnes, O.B.; Aarbakke, G.M.; Verhoeven, A.J.; Holmsen, H.

    1985-01-01

    Different ratios of radioactive polyphosphoinositides in platelets pulse-labelled with 32p-orthophosphate have been reported by various laboratories. We studied whether these differences originate from differences in methodology. Extracts of 32p-Pi labelled human platelets were prepared at various times after gel-filtration and phosphatidylinositol (PI)-, mono (PIP)- and bisphosphate (PIP2) were separated by thin-layer chromatography using four different solvent systems. The 32p-levels in PIP and PIP2 remained constant during one hour after gel-filtration, whereas 32p-PI increased continuously and more than doubled within the first h. In two of the systems PIP co-chromatographed with a radioactive compound which separated well from PIP in the two other systems. This unknown compound was also labelled with 3H-glycerol, 3H-inositol and 3H-arachidonic acid, but it was metabolically and functionally different from the polyphosphoinositides. Both the co-chromatography of this unknown phospholipid and the increase in 32p-PI in gel-filtered platelets can explain the difference in 32p-labelling in phosphoinositides reported in the literature

  12. A Simple Thin Layer Chromatography Method for Separation of Selected Natural Steroid Hormones

    International Nuclear Information System (INIS)

    Nowakowska, J.; Rudnicka-Litka, K.; Ciura, K.; Pikul, P.; Piotrowicz, J.

    2015-01-01

    Chromatographic properties of seven steroids: estrogens (β-estradiol and estrone), androgens (testosterone, methyltestosterone, trans-androsterone), progesterone and cholesterol have been studied by planar chromatography with usage of High Performance Thin Layer Chromatography (HPTLC) and Thin Layer Chromatography (TLC) plates. Normal, reversed and cyano-bonded silica stationary phases were tested with five binary mobile phases (acetonitrile-water, acetonitrile-DMSO, acetonitrile-methanol, acetone-petroleum ether, acetone-water) in which the concentration of organic modifier varied from 0 to 100 % (v/v). This study reports the optimization of steroid hormones separation. Principal Component Analysis (PCA) based on calculated molecular descriptors quantitatively differentiating solutes was performed in order to investigate the similarity and dissimilarity between tested compounds. The separation abilities of mobile and stationary phases were compared based on separation factor α. Chromatographic retention data and possible retention mechanisms also were discussed. (author)

  13. Thin layer chromatographic analysis of some common over the counter (OTC cough–cold preparations

    Directory of Open Access Journals (Sweden)

    Manpreet Kaur Chahal

    2016-12-01

    Full Text Available In the present study, potential utility of thin layer chromatography to differentiate some common OTC cough–cold preparations was evaluated. Twenty solvent systems were examined from which a solvent systems A comprising methanol:ammonia in the ratio of 100:1.5 (v/v and B comprising chloroform:methanol in the ratio of 90:10 (v/v were found to be most suitable as it showed a high degree of separation of different components of these preparations. It was also found that iodine fuming technique is the best visualizing method for examining the TLC chromatograms of these drug samples prior to subsequent instrumental analysis.

  14. The weight of flash chromatography: A tool to predict its mass intensity from thin-layer chromatography

    Directory of Open Access Journals (Sweden)

    Freddy Pessel

    2016-11-01

    Full Text Available Purification by flash chromatography strongly impacts the greenness of a process. Unfortunately, due to the lack of the relevant literature data, very often this impact cannot be assessed thus preventing the comparison of the environmental factors affecting the syntheses. We developed a simple mathematical approach to evaluate the minimum mass intensity of flash chromatography from the retention factor values determined by thin-layer chromatography.

  15. A reversed-phase compatible thin-layer chromatography autography for the detection of acetylcholinesterase inhibitors.

    Science.gov (United States)

    Ramallo, I Ayelen; García, Paula; Furlan, Ricardo L E

    2015-11-01

    A dual readout autographic assay to detect acetylcholinesterase inhibitors present in complex matrices adsorbed on reversed-phase or normal-phase thin-layer chromatography plates is described. Enzyme gel entrapment with an amphiphilic copolymer was used for assay development. The effects of substrate and enzyme concentrations, pH, incubation time, and incubation temperature on the sensitivity and the detection limit of the assay were evaluated. Experimental design and response surface methodology were used to optimize conditions with a minimum number of experiments. The assay allowed the detection of 0.01% w/w of physostigmine in both a spiked Sonchus oleraceus L. extract chromatographed on normal phase and a spiked Pimenta racemosa (Mill.) J.W. Moore leaf essential oil chromatographed on reversed phase. Finally, the reversed-phase thin-layer chromatography assay was applied to reveal the presence of an inhibitor in the Cymbopogon citratus (DC.) Stapf essential oil. The developed assay is able to detect acetylcholinesterase inhibitors present in complex matrixes that were chromatographed in normal phase or reversed-phase thin-layer chromatography. The detection limit for physostigmine on both normal and reversed phase was of 1×10(-4) μg. The results can be read by a change in color and/or a change in fluorescence. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Chromatography.

    Science.gov (United States)

    Brantley, L. Reed, Sr.; Demanche, Edna L.; Klemm, E. Barbara; Kyselka, Will; Phillips, Edwin A.; Pottenger, Francis M.; Yamamoto, Karen N.; Young, Donald B.

    This booklet presents some activities on chromatography. Directions for preparing leaf pigment extracts using alcohol are given, and paper chromatography and thin-layer chromatography are described as modifications of the basic principles of chromatography. (KHR)

  17. Reversed-phase thin-layer chromatography of the rare earth elements

    International Nuclear Information System (INIS)

    Kuroda, R.; Adachi, M.; Oguma, K.

    1988-01-01

    Partition chromatographic behaviour of the rare earth elements on C 18 bonded silica reversed-phase material has been investigated by thin-layer chromatography in methanol - lactate media. The rare earth lactato complexes are distributed and fractionated on bonded silica layers without ion-interaction reagents. The concentration and pH of lactate solution, methanol concentration and temperature have effects on the migration and resolution of the rare earth elements. The partition system is particularly suited to separate adjacent rare earths of middle atomic weight groups, allowing the separation of gadolinium, terbium, dysprosium, holmium, erbium and thulium to be achieved by development to 18 cm distance. (orig.)

  18. Extraction of oxytetracycline starting from the meats of chickens and identifications by thin layer chromatography

    International Nuclear Information System (INIS)

    Elghozzi, Amira

    2007-01-01

    Use of antibiotics in the poultry also suspected as one of the cause of the emergence of resistance to antibiotics of some bacteria what causes risks on human health continuation of persistence of the residues in the foodstuffs. We were interested in detected the presence qualitatively of oxytetracyclin in samples of muscle and liver of chicken by the use of the techniques of thin layer chromatography. Although, These results are satisfactory, it is always necessary to prevent the dangers which cause the risks of the residues of oxytetracycline on health. (Author). 20 refs

  19. Separation of Berberine Hydrochloride and Tetrahydropalmatine and Their Quantitative Analysis with Thin Layer Chromatography Involved with Ionic Liquids

    Directory of Open Access Journals (Sweden)

    Jing Lu

    2015-01-01

    Full Text Available [BMIM]OH was used in mobile and stationary phase of thin layer chromatography (TLC to analyze berberine hydrochloride and tetrahydropalmatine for the first time. Supported imidazole ionic liquid with hydroxide ion on silica gel (SiO2·Im+·OH− was synthesized through simple procedure and characterized by Fourier transform infrared spectroscopy (FT-IR, elemental analysis, and scanning electron microscope (SEM. Moreover, on the plates prepared by SiO2·Im+·OH−, the contents of the above alkaloids in the Chinese patent medicine (CPM of “Stomacheasy” capsule were successfully determined by TLC scanner. The key conditions and chromatographic behaviors were also investigated in detail. According to similar ways, ionic liquids (ILs also can be used in other planar chromatographies in two modes. This study is expected to be helpful in expanding the application of IL and its bonded silica gel in TLC separation field.

  20. [Analysis of pigments from Rhodotorula glutinis by Raman spectroscopy and thin layer chromatography].

    Science.gov (United States)

    Yuan, Yu-feng; Tao, Zhan-hua; Wang, Xue; Li, Yong-qing; Liu, Jun-xian

    2012-03-01

    The pigments from Rhodotorula glutinis were separated by using thin layer chromatography, and the result showed that Rhodotorula glutinis cells could synthesize at least three kinds of pigments, which were beta-carotene, torulene, and torularhodin. The Raman spectra based on the three pigments were acquired, and original spectra were preprocessed by background elimination, baseline correction, and three-point-smoothing, then the averaged spectra from different pigments were investigated, and the result indicated that Raman shift which represents C-C bond was different, and the wave number of beta-carotene demonstrated the largest deviation, finally torulene and torularhodin in Rhodotorula glutinis had more content than beta-carotene. Quantitative analysis of Raman peak height ratio revealed that peak height ratio of pigments showed little difference, which could be used as parameters for further research on living cells, providing reference content of pigments. The above results suggest that Raman spectroscopy combined with thin layer chromatography can be applied to analyze pigments from Rhodotorula glutinis, provides abundant information about pigments, and serves as an effective method to study pigments.

  1. Determination of radiochemical yields of 186Re-labelled complexes using thin layer chromatography

    International Nuclear Information System (INIS)

    Konirova, R.; Kohlickova, M.; Jedinakova-Krizova, V.

    1999-01-01

    The reaction conditions for synthesis of three rhenium complexes 186 Re-methylendiphosphonate (MDP), 186 Re-hydroxyethylidendiphosphonate (HEDP) and 186 Re-citrate have been investigated. Radiochemical yield of complexation has been determined by thin layer chromatography and paper chromatography. The rhenium complexation with corresponding ligand is dependent on pH values of reaction mixture, concentration of studied ligand (MDP, HEDP and sodium citrate) and concentration of reducing agent. Stannous chloride with ascorbic acid (as antioxidant) was used for reduction of perrhenate. The labeling yield of 186 Re-MDP was about 90 %, of 186 Re-HEDP more than 80 % and more than 75 % for 186 Re-citrate under optimum conditions. Besides, the possibility of application of porphyrins as organic ligands for complexation with rhenium isotopes is examined. (authors)

  2. Reversed-phase thin-layer chromatography behavior of aldopentose derivatives

    Directory of Open Access Journals (Sweden)

    Malbaša Radomir V.

    2012-01-01

    Full Text Available Quantitative structure-retention relationships (QSRR have been used to study the chromatographic behavior of some aldopentose. The behavior of aldopentose derivatives was investigated by means of the reversed-phase thin-layer chromatography (RP TLC on the silica gel impregnated with paraffin oil stationary phases. Binary mixtures of methanol-water, acetone-water and dioxane-water were used as mobile phases. Retention factors, RM0, corresponding to zero percent organic modifier in the aqueous mobile phase was determined. Lipophilicity C0 was calculated as the ratio of the intercept and slope values. There was satisfactory correlation between them and log P values calculated using different theoretical procedures. Some of these correlations offer very good predicting models, which are important for a better understanding of the relationships between chemical structure and retention. The study showed that the hydrophobic parameters RM0 and C0 can be used as a measures of lipophilicity of investigated compounds.

  3. DIFFERENTIATION OF Curcuma longa, Curcuma xanthorrhiza and Zingiber cassumunar BY THIN LAYER CHROMATOGRAPHY FINGERPRINT ANALYSIS

    Directory of Open Access Journals (Sweden)

    Mohamad Rafi

    2011-07-01

    Full Text Available Turmeric (Curcuma longa, java turmeric (Curcuma xanthorrhiza and cassumunar ginger (Zingiber cassumunar are widely used in traditional Indonesian medicine. These three herbs have relatively similar rhizomes colour so it is difficult to be differentiated especially if they are in powder form. A rapid and reliable method, thin layer chromatography (TLC fingerprint, has been developed in order to identify, authenticate and differentiate these three herbs through fingerprint profile of chemical compounds. TLC fingerprints of the three herbs were obtained by visualization of separate zones with visible and UV (254 and 366 nm light. The TLC fingerprint pattern is different each other and showed a specific marker zones respectively. Therefore, TLC fingerprint can be utilized for identification, authentication and differentiation method in quality control of the three herbs tested.

  4. High performance thin layer chromatography fingerprint analysis of guava (Psidium guajava) leaves

    Science.gov (United States)

    Astuti, M.; Darusman, L. K.; Rafi, M.

    2017-05-01

    High-performance thin layer chromatography (HPTLC) fingerprint analysis is commonly used for quality control of medicinal plants in term of identification and authentication. In this study, we have been developed HPTLC fingerprint analysis for identification of guava (Psidium guajava) leaves raw material. A mixture of chloroform, acetone, and formic acid in the ratio 10:2:1 was used as the optimum mobile phase in HPTLC silica plate and with 13 bands were detected. As reference marker we chose gallic acid (Rf = 0.21) and catechin (Rf = 0.11). The two compound were detected as pale black bands at 366 nm after derivatization with sulfuric acid 10% v/v (in methanol) reagent. Validation of the method was met within validation criteria, so the developed method could be used for quality control of guava leaves.

  5. Digitally enhanced thin layer chromatography: further development and some applications in isotopic chemistry.

    Science.gov (United States)

    Manthorpe, Daniel P; Lockley, William J S

    2013-09-01

    Improvements to thin layer chromatography (TLC) analysis can be made easily and cheaply by the application of digital colour photography and image analysis. The combined technique, digitally enhanced TLC (DE-TLC), is applicable to the accurate quantification of analytes in mixtures, to reaction monitoring and to other typical uses of TLC. Examples are given of the application of digitally enhanced TLC to: the deuteromethylations of theophylline to [methyl-(2)H3]caffeine and of umbelliferone to [(2)H3]7-methoxycoumarin; the selection of tertiary amine bases in deuterodechlorination reactions; stoichiometry optimisation in the borodeuteride reduction of quinizarin (1,4-dihydroxyanthraquinone) and to the assessment of xanthophyll yields in Lepidium sativum seedlings grown in deuterated media. Copyright © 2013 John Wiley & Sons, Ltd.

  6. Effect-directed analysis via hyphenated high-performance thin-layer chromatography for bioanalytical profiling of sunflower leaves.

    Science.gov (United States)

    Móricz, Ágnes M; Ott, Péter G; Yüce, Imanuel; Darcsi, András; Béni, Szabolcs; Morlock, Gertrud E

    2018-01-19

    High-performance thin-layer chromatography (HPTLC) coupled with effect-directed analysis was used for non-targeted screening of sunflower leaf extract for components exhibiting antioxidant, antibacterial and/or cholinesterase enzyme inhibitory effects. The active compounds were characterized by HPTLC-electrospray ionization-high resolution mass spectrometry (ESI-HRMS) and HPTLC-Direct Analysis in Real Time (DART)-MS/MS. The latter ambient ionization technique (less soft than ESI) resulted in oxidation and fragmentation products and characteristic fragment ions. NMR spectroscopy after targeted isolation via preparative normal phase flash chromatography and semi-preparative reversed phase high-performance liquid chromatography supported the identification of two diterpenes to be (-)-kaur-16-en-19-oic acid and 15-α-angeloyloxy-ent-kaur-16-en-19-oic acid. Both compounds found to be multi-potent as they inhibited acetylcholinesterase and butyrylcholinesterase and showed antibacterial effects against Gram-positive Bacillus subtilis and Gram-negative Aliivibrio fischeri bacteria. Kaurenoic acid was also active against the Gram-negative pepper pathogenic Xanthomonas euvesicatoria bacteria. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. DETECTION, ISOLATION, AND IDENTIFICATION OF TRUXILLINES IN ILLICIT COCAINE BY MEANS OF THIN-LAYER CHROMATOGRAPHY AND MASS-SPECTROMETRY

    NARCIS (Netherlands)

    ENSING, JG; DEZEEUW, RA

    By means of thin-layer chromatography, an unidentified alkaloidal fraction was observed in illicit cocaine. Because of its persisting presence, efforts were undertaken to isolate and identify this fraction. Various analytical techniques showed complex results, finally pointing to the possibility of

  8. Extraction of Nutraceuticals from Spirulina (Blue-Green Alga): A Bioorganic Chemistry Practice Using Thin-layer Chromatography

    Science.gov (United States)

    Herrera Bravo de Laguna, Irma; Toledo Marante, Francisco J.; Luna-Freire, Kristerson R.; Mioso, Roberto

    2015-01-01

    Spirulina is a blue-green alga (cyanobacteria) with high nutritive value. This work provides an innovative and original approach to the consideration of a bioorganic chemistry practice, using Spirulina for the separation of phytochemicals with nutraceutical characteristics via thin-layer chromatography (TLC) plates. The aim is to bring together…

  9. Thin layer chromatography: a simple and reliable technique for the determination of pesticides residue in environmental samples

    International Nuclear Information System (INIS)

    Asi, M.R.; Hussain, A.; Iqbal, Z.; Chaudhary, J.A.

    2000-01-01

    A method for the detection of pesticides by thin-layer chromatography is described. These pesticides on chlorination and treatment with 0-toluidine, yield an intensively colored blue product. Some of the organophosphates and carbonates can be determined at low level (mu g/ g) by this method. The limit of minimum detectable quantity is 10-100 ng. (author)

  10. In situ identification of high-performance thin-layer chromatography spots by fourier transform surface-enhanced Raman scattering

    Science.gov (United States)

    Koglin, Eckhardt; Kramer, Hella; Sawatski, Juergen; Lehner, Carolin; Hellman, Janice L.

    1994-01-01

    FT-SERS has been used to identify samples supported on high-performance thin-layer chromatography plates. The TLC plates were sprayed with colloidal silver solutions which resulted in enhancement of the FT-Raman scattering of these biologically and environmentally important compounds.

  11. The laser desorption/laser ionization mass spectra of some methylated xanthines and the laser desorption of caffeine and theophylline from thin layer chromatography plates

    Science.gov (United States)

    Rogers, Kevin; Milnes, John; Gormally, John

    1993-02-01

    Laser desorption/laser ionization time-of-flight mass spectra of caffeine, theophylline, theobromine and xanthine are reported. These mass spectra are compared with published spectra obtained using electron impact ionization. Mass spectra of caffeine and theophylline obtained by IR laser desorption from thin layer chromatography plates are also described. The laser desorption of materials from thin layer chromatography plates is discussed.

  12. Bacterial Cell Wall Precursor Phosphatase Assays Using Thin-layer Chromatography (TLC) and High Pressure Liquid Chromatography (HPLC).

    Science.gov (United States)

    Pazos, Manuel; Otten, Christian; Vollmer, Waldemar

    2018-03-20

    Peptidoglycan encases the bacterial cytoplasmic membrane to protect the cell from lysis due to the turgor. The final steps of peptidoglycan synthesis require a membrane-anchored substrate called lipid II, in which the peptidoglycan subunit is linked to the carrier lipid undecaprenol via a pyrophosphate moiety. Lipid II is the target of glycopeptide antibiotics and several antimicrobial peptides, and is degraded by 'attacking' enzymes involved in bacterial competition to induce lysis. Here we describe two protocols using thin-layer chromatography (TLC) and high pressure liquid chromatography (HPLC), respectively, to assay the digestion of lipid II by phosphatases such as Colicin M or the LXG toxin protein TelC from Streptococcus intermedius . The TLC method can also monitor the digestion of undecaprenyl (pyro)phosphate, whereas the HPLC method allows to separate the di-, mono- or unphosphorylated disaccharide pentapeptide products of lipid II.

  13. Indirect fluorometric detection techniques on thin layer chromatography and effect of ultrasound on gel electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Yinfa, Ma.

    1990-12-10

    Thin-layer chromatography (TLC) is a broadly applicable separation technique. It offers many advantages over high performance liquid chromatography (HPLC), such as easily adapted for two-dimensional separation, for whole-column'' detection and for handling multiple samples, etc. However, due to its draggy development of detection techniques comparing with HPLC, TLC has not received the attention it deserves. Therefore, exploring new detection techniques is very important to the development of TLC. It is the principal of this dissertation to present a new detection method for TLC -- indirect fluorometric detection method. This detection technique is universal sensitive, nondestructive, and simple. This will be described in detail from Sections 1 through Section 5. Section 1 and 3 describe the indirect fluorometric detection of anions and nonelectrolytes in TLC. In Section 2, a detection method for cations based on fluorescence quenching of ethidium bromide is presented. In Section 4, a simple and interesting TLC experiment is designed, three different fluorescence detection principles are used for the determination of caffeine, saccharin and sodium benzoate in beverages. A laser-based indirect fluorometric detection technique in TLC is developed in Section 5. Section 6 is totally different from Sections 1 through 5. An ultrasonic effect on the separation of DNA fragments in agarose gel electrophoresis is investigated. 262 refs.

  14. Utilization of thin-layer chromatography for confirmational sampling during remedial excavation

    International Nuclear Information System (INIS)

    Burton, P.J.

    1996-01-01

    Thin-layer chromatography (TLC) is a simple, efficient, inexpensive, and accurate method of chemical analysis. This method is applicable to field testing for confirming the limits of excavation during excavation of petroleum, oil, and/or lubricant (POL) contamination. Traditionally, excavation at contaminated sites suffers from a time delay due to the need to obtain laboratory confirmation of the limits of excavation. All suspected contaminated material is removed for stockpiling or remediation. The remaining soils need to be sampled to confirm that no contaminated material remains in the excavation. The site scientist collects samples and sends them out for analysis at a certified laboratory. The laboratory requires, even for a rush order, several days to analyze the samples. This time delay interferes with the efficiency of the operation. The excavations either have to be left open (which is a safety hazard) or reopened if additional material must be excavated. TLC samples can be collected and analyzed in several hours allowing for a short turnaround time for analytical results. The TLC method can be easily performed by a technician. Results of a case study from a subarctic Alaskan site will be reported. Simple operational TLC procedures will be shared. The equipment required for TLC analysis will be outlined. Correlation data between TLC and laboratory analysis will be presented

  15. HPTLC-aptastaining - Innovative protein detection system for high-performance thin-layer chromatography

    Science.gov (United States)

    Morschheuser, Lena; Wessels, Hauke; Pille, Christina; Fischer, Judith; Hünniger, Tim; Fischer, Markus; Paschke-Kratzin, Angelika; Rohn, Sascha

    2016-05-01

    Protein analysis using high-performance thin-layer chromatography (HPTLC) is not commonly used but can complement traditional electrophoretic and mass spectrometric approaches in a unique way. Due to various detection protocols and possibilities for hyphenation, HPTLC protein analysis is a promising alternative for e.g., investigating posttranslational modifications. This study exemplarily focused on the investigation of lysozyme, an enzyme which is occurring in eggs and technologically added to foods and beverages such as wine. The detection of lysozyme is mandatory, as it might trigger allergenic reactions in sensitive individuals. To underline the advantages of HPTLC in protein analysis, the development of innovative, highly specific staining protocols leads to improved sensitivity for protein detection on HPTLC plates in comparison to universal protein derivatization reagents. This study aimed at developing a detection methodology for HPTLC separated proteins using aptamers. Due to their affinity and specificity towards a wide range of targets, an aptamer based staining procedure on HPTLC (HPTLC-aptastaining) will enable manifold analytical possibilities. Besides the proof of its applicability for the very first time, (i) aptamer-based staining of proteins is applicable on different stationary phase materials and (ii) furthermore, it can be used as an approach for a semi-quantitative estimation of protein concentrations.

  16. Development and validation of a thin-layer chromatography method for stability studies of naproxen

    International Nuclear Information System (INIS)

    Rodriguez Hernandez, Yaslenis; Suarez Perez, Yania; Garcia Pulpeiro, Oscar; Rodriguez Borges, Tania

    2011-01-01

    The validation of an analytical method was carried out to be applied to the stability studies of the future formulations of naproxen suppositories for infant and adult use. The factors which mostly influenced in the naproxen stability were determined, the major degradation occurred in oxidizing acid medium and by action of light. The possible formation of esters between the free carboxyl group present in naproxen and the glyceryl monoestereate present in the base was identified as one of the degradation paths in the new formulation. The results were satisfactory. A thin-layer chromatography-based method was developed as well as the best chromatographic conditions were selected. GF 254 silica gel plates and ultraviolet developer at 254 nm were employed. Three solvent systems were evaluated of which A made up of glacial acetic: tetrahydrofurane:toluene (3:9:90 v/v/v)allowed adequate resolution between the analyte and the possible degradation products, with detection limit of 1 μg. The use of the suggested method was restricted to the identification of possible degradation products just for qualitative purposes and not as final test. The method proved to be sensitive and selective enough to be applied for the stated objective, according to the validation results

  17. Determination of plasma aldosterone in children by thin layer chromatography and radioimmunoassay

    Energy Technology Data Exchange (ETDEWEB)

    Parth, K; Zimprich, H; Brunel, R [The Ludwig Boltzmann Institute of Paediatric Endocrinology; The Karolinen Kinderspital, Vienna)

    1976-01-01

    An accurate and relatively simple radioimmunoassay for the determination of aldosterone concentration in peripheral plasma has been developed. 0.5-2.0 ml plasma with added ..cap alpha..1.2-/sup 3/H..omega..aldosterone is extracted with dichloromethane. Purification of the extract is achieved by thin layer chromatography in the system benzene-acetone 1:1. Recovery of ..cap alpha..1,2-/sup 3/H..omega..aldosterone is 58+-6 (sd) %. Bound and free fractions are separated by dextran-coated charcol. The intra-assay reproducibility is 8.8 % and the inter-assay reproducibility varies from 11.4-16.1%. The sensitivity of the assay for a 5 ml plasma sample can be put at 0.2 ng/100 ml. Normal values determined in 52 healthy children of different age groups are presented. Furthermore the aldosterone stimulating effect of low sodium diet (17 children), severe and prolonged vomiting (19 children) and synthetic ACTH (10 children) has been studied by our modified method.

  18. Molecular Ionization-Desorption Analysis Source (MIDAS) for Mass Spectrometry: Thin-Layer Chromatography

    Science.gov (United States)

    Winter, Gregory T.; Wilhide, Joshua A.; LaCourse, William R.

    2016-02-01

    Molecular ionization-desorption analysis source (MIDAS), which is a desorption atmospheric pressure chemical ionization (DAPCI) type source, for mass spectrometry has been developed as a multi-functional platform for the direct sampling of surfaces. In this article, its utility for the analysis of thin-layer chromatography (TLC) plates is highlighted. Amino acids, which are difficult to visualize without staining reagents or charring, were detected and identified directly from a TLC plate. To demonstrate the full potential of MIDAS, all active ingredients from an analgesic tablet, separated on a TLC plate, were successfully detected using both positive and negative ion modes. The identity of each of the compounds was confirmed from their mass spectra and compared against standards. Post separation, the chemical signal (blue permanent marker) as reference marks placed at the origin and solvent front were used to calculate retention factor (Rf) values from the resulting ion chromatogram. The quantitative capabilities of the device were exhibited by scanning caffeine spots on a TLC plate of increasing sample amount. A linear curve based on peak are, R2 = 0.994, was generated for seven spots ranging from 50 to 1000 ng of caffeine per spot.

  19. Surface enhanced Raman scattering imaging of developed thin-layer chromatography plates.

    Science.gov (United States)

    Freye, Chris E; Crane, Nichole A; Kirchner, Teresa B; Sepaniak, Michael J

    2013-04-16

    A method for hyphenating surface enhanced Raman scattering (SERS) and thin-layer chromatography (TLC) is presented that employs silver-polymer nanocomposites as an interface. Through the process of conformal blotting, analytes are transferred from TLC plates to nanocomposite films before being imaged via SERS. A procedure leading to maximum blotting efficiency was established by investigating various parameters such as time, pressure, and type and amount of blotting solvent. Additionally, limits of detection were established for test analytes malachite green isothiocyanate, 4-aminothiophenol, and Rhodamine 6G (Rh6G) ranging from 10(-7) to 10(-6) M. Band broadening due to blotting was minimal (∼10%) as examined by comparing the spatial extent of TLC-spotted Rh6G via fluorescence and then the SERS-based spot size on the nanocomposite after the blotting process. Finally, a separation of the test analytes was carried out on a TLC plate followed by blotting and the acquisition of distance × wavenumber × intensity three-dimensional TLC-SERS plots.

  20. On-chip ultra-thin layer chromatography and surface enhanced Raman spectroscopy.

    Science.gov (United States)

    Chen, Jing; Abell, Justin; Huang, Yao-wen; Zhao, Yiping

    2012-09-07

    We demonstrate that silver nanorod (AgNR) array substrates can be used for on-chip separation and detection of chemical mixtures by combining ultra-thin layer chromatography (UTLC) and surface enhanced Raman spectroscopy (SERS). The UTLC-SERS plate consists of an AgNR array fabricated by oblique angle deposition. The capability of the AgNR substrates to separate the different compounds in a mixture was explored using a mixture of four dyes and a mixture of melamine and Rhodamine 6G at varied concentrations with different mobile phase solvents. After UTLC separation, spatially-resolved SERS spectra were collected along the mobile phase development direction and the intensities of specific SERS peaks from each component were used to generate chromatograms. The AgNR substrates demonstrate the potential for separating the test dyes with plate heights as low as 9.6 μm. The limits of detection are between 10(-5)-10(-6) M. Furthermore, we show that the coupling of UTLC with SERS improves the SERS detection specificity, as small amounts of target analytes can be separated from the interfering background components.

  1. [Analysis of phthalates in plastic food-packaging bags by thin layer chromatography].

    Science.gov (United States)

    Chen, Hui; Wang, Yuan; Zhu, Ruohua

    2006-01-01

    The method for simultaneous determination of four phthalates, namely dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DBP) and di (2-ethylhexyl) phthalate (DEHP) in plastic food-packaging bags by thin layer chromatography (TLC) was developed. The plastic food-packaging bags were extracted with ethanol by ultrasonication, then the mixture was filtrated through membrane (0.45 microm). The mixture of ethyl acetate-anhydrous ether-isooctane (1 : 4 : 15, v/v) was used as developing agent on the TLC silica gel plate for development. The filtered liquid was spotted on the TLC plate dealt by acetone, and detected with scanning wavelength of 275 nm and reference wavelength of 340 nm. The qualitative analysis of the phthalates was performed using the R(f) values of the chromatogram. The quantitative analysis was performed with external standard method. Good linearities were obtained for DMP, DEP, DBP and DEHP. The detection limits were 2.1 ng for DMP, 2.4 ng for DEP, 3.4 ng for DBP and 4.0 ng for DEHP. The relative standard deviations (RSDs) of the four phthalates were 2.8% - 3.5%. The recoveries of the four phthalate standards in real sample were 78.58% - 111.04%. The method presented has the advantages of high precision, high sensitivity, small sample size, and simple pretreatment . The method was used to detect the four phthalates in the food-packaging bags. The contents in real samples were close to the results by gas chromatography.

  2. Preparation of thin layers of BiSrCaCuO by method MOCVD

    International Nuclear Information System (INIS)

    Beran, P.; Stejskal, J.; Strejc, A.; Nevriva, M.; Sedmibudsky, D.; Leitner, J.

    1999-01-01

    Preparation of superconducting material on the basis mixed oxides of BiSrCaCuO by chemical vapour deposition (CVD) method is described. Surface morphology and concentration profiles of elements were analyzed by scanning electron microscope and microprobe. Phase of layers was analysed by X-ray diffraction (radiation of Cu kα ). Samples of thin layers were characterized by magnetic susceptibility in temperature interval 10 to 150 K. Obtained results confirm formation of superconducting phases Bi 2 Sr 2 Ca 1 Cu 2 O x and Bi 2 Sr 2 Xa 2 Cu 3 O x

  3. The phytochemical screening and thin layer chromatography results of Jatropha gossypiifolia seeds

    Directory of Open Access Journals (Sweden)

    Anis Nurwidayati

    2013-05-01

    , the intermediary for schistosomiasis is widespread in this region. Eradication has been done by spraying chemical molluscicides. This study aimed to identify the class of chemical compounds in the methanol extract of red castor seed.Methods: The study was conducted in May 2009. Red castor seeds were collected from Palu, Central Sulawesi. Red castor seeds extraction was done by percolation method using methanol solvent. Phytochemical screening test was performed with a tube to detect the compound in red castor bean extract. Screening was followed by thin layer chromatography testing to ensure the screening results of the test tube.Results:Extracts that was produced from 500 grams of red castor dry seed powder with 2500 ml of methanol solvent was 250 ml thick reddish brown fluid. Phytochemical screening with a test tube showed positive results of alkaloid by the formation of deposits in Meyer test, Wagner test, and Dragendorff test. Screening the methanol extracts of red castor seed also showed positive results on saponins by foam test and LiebermanBurchard test. Positive results on Killiani Keller tests and Kedde test suggests that red castor bean extract contains cardenoline and bufadienol. Thin-layer chromatography analysis showed that the red castor bean extract is positive for terpenes with the formation of spots on the silica gel plate when terpenes was sprayed (cerium sulfate reagent. Conclusion: Chemical components contained in the methanol extract of red castor beans consisted of alkaloids, saponins, cardenolin, bufadienol, and terpenes. (Health Science Indones 2012;2:xx-xxKeywords: schistosomiasis, Jatropha gossypifolia, chemical compound

  4. Nevoid melanoma of the vagina: report of one case diagnosed on thin layer cytological preparations

    Directory of Open Access Journals (Sweden)

    Ascierto Paolo

    2007-01-01

    Full Text Available Abstract Background Primary melanoma of the vagina is an extremely rare neoplasm with approximately 250 reported cases in the world literature 1234. In its amelanotic variant this lesion may raise several differential diagnostic problems in cytological specimens 5. In this setting, the usage of thin layer cytopathological techniques (Liquid Based Preparations = LBP may enhance the diagnostic sensitivity by permitting immunocytochemical study without having to repeat the sampling procedure. The aim of this paper is to describe the cytomorphological presentation of primary vaginal melanoma on LBP since it has not previously been reported up to now, to our knowledge. Case presentation a 79-y-o female complaining of vulvar itching and yellowish vaginal discharge underwent a complete gynaecological evaluation during which a LBP cytological sample was taken from a suspicious whitish mass protruding into the vaginal lumen. A cytopathological diagnosis of amelanotic melanoma was rendered. The mass was radically excised and the patient was treated with α-Interferon. Conclusion amelanotic melanoma may be successfully diagnosed on LBP cytological preparations. Thin layer preparations may enhance the diagnostic cytomorphological clues to its diagnosis and may permit an adequate immunocytochemical characterization of the neoplasm.

  5. Nevoid melanoma of the vagina: report of one case diagnosed on thin layer cytological preparations.

    Science.gov (United States)

    Fulciniti, Franco; Ascierto, Paolo Antonio; Simeone, Ester; Bove, Patrizia; Losito, Simona; Russo, Serena; Gallo, Maria Stella; Greggi, Stefano

    2007-07-03

    Primary melanoma of the vagina is an extremely rare neoplasm with approximately 250 reported cases in the world literature 1234. In its amelanotic variant this lesion may raise several differential diagnostic problems in cytological specimens 5. In this setting, the usage of thin layer cytopathological techniques (Liquid Based Preparations = LBP) may enhance the diagnostic sensitivity by permitting immunocytochemical study without having to repeat the sampling procedure. The aim of this paper is to describe the cytomorphological presentation of primary vaginal melanoma on LBP since it has not previously been reported up to now, to our knowledge. a 79-y-o female complaining of vulvar itching and yellowish vaginal discharge underwent a complete gynaecological evaluation during which a LBP cytological sample was taken from a suspicious whitish mass protruding into the vaginal lumen. A cytopathological diagnosis of amelanotic melanoma was rendered. The mass was radically excised and the patient was treated with alpha-Interferon. amelanotic melanoma may be successfully diagnosed on LBP cytological preparations. Thin layer preparations may enhance the diagnostic cytomorphological clues to its diagnosis and may permit an adequate immunocytochemical characterization of the neoplasm.

  6. High Performance Thin Layer Chromatography method for analysis of 3,4-methylenedioxymethamphetamine in seized tablets

    Directory of Open Access Journals (Sweden)

    Boris E. Duffau

    2015-12-01

    Full Text Available Context: Consumption of synthetic drugs had increased in recent years, used as a recreational drug by young people who presume that consumption of this drug is harmless for health; however clinical studies have shown that this stimulant and its metabolites are toxic. Due to these reasons, chemical analysis of this illicit drug is crucial from the points of view of occupational medicine, toxicology, and law enforcement with the aim of pursuit the traffic of illegal drug. Aims: Implement and fully validate a rapid and simple method for detection and quantitation of MDMA by High-Performance Thin Layer Chromatography in seized samples. Methods: With the implemented method was analyzed 12 positive samples seized by Chilean police, to found the concentration of MDMA in ecstasy tablets. Results: The method was fully validated, the linearity of the method was evaluated by the calibration curve between 51.0 – 510.0 µg/band (R2 0.9977; limit of detection was 12.1 µg per band, and limit of quantitation was 36.8 µg per band. The precision of the method (RSD was lower than 5.0%. Accuracy was evaluated by determination of the percentage of MDMA recovered by the assay (99.13%, and relative Uncertainty was 6.66%. With this method, it was analyzed real seized samples of MDMA, results showed that all samples contained MDMA and concentration was between 18.15 – 59.84 % w/w. Conclusions: The method is selective, sensitive, and specific, with possible application in forensic analysis. To the best of our knowledge, this is the first report about concentration of MDMA in ecstasy pills in Chile.

  7. Stable, microfabricated thin layer chromatography plates without volume distortion on patterned, carbon and Al₂O₃-primed carbon nanotube forests.

    Science.gov (United States)

    Jensen, David S; Kanyal, Supriya S; Gupta, Vipul; Vail, Michael A; Dadson, Andrew E; Engelhard, Mark; Vanfleet, Richard; Davis, Robert C; Linford, Matthew R

    2012-09-28

    Some of us recently described the fabrication of thin layer chromatography (TLC) plates from patterned carbon nanotube (CNT) forests via direct infiltration/coating of the CNTs by low pressure chemical vapor deposition (LPCVD) of silicon from SiH₄, followed by high temperature oxidation of the CNTs and Si. Herein we present an improved microfabrication process for the preparation of these TLC plates. First, a few nanometers of carbon and/or a thin film of Al₂O₃ is deposited on the CNTs. This method of priming the CNTs for subsequent depositions appears to be new. X-ray photoelectron spectroscopy confirms the presence of additional oxygen after carbon deposition. After priming, the plates are coated by rapid, conformal deposition of an inorganic material that does not require subsequent oxidation, i.e., by a fast pseudo atomic layer deposition (ψ-ALD) of SiO₂ from trimethylaluminum and tris(tert-butoxy)silanol. Unlike devices described previously, faithful reproduction of the features in the masks is still observed after oxidation. A bonded, amino phase on the resulting plates shows fast, highly efficient separations of fluorescent dyes (plate heights in the range of 1.6-7.7 μm). Extensive characterization of the new materials by TEM, SEM, EDAX, DRIFT, and XPS is reported. A substantially lower process temperature for the removal of the CNT scaffold is possible as a result of the already oxidized materials used. Copyright © 2012 Elsevier B.V. All rights reserved.

  8. Complete Analysis of a Biologically Active Tetrapeptide: A Project Utilizing Thin-Layer Chromatography and Tandem Quadrupole Mass Spectrometry

    Science.gov (United States)

    Lefevre, Joseph W.; Dodsworth, David W.

    2000-04-01

    The biologically active tetrapeptide d-Ala-Gly-l-Phe-d-Leu ([des-Tyr1-d-Ala2-d-Leu5]enkephalin) was analyzed for its amino acid content and stereochemistry by normal and reversed-phase thin-layer chromatography (TLC), and its sequence was determined by tandem quadrupole mass spectrometry. The project involved sequential N-dansylation of a portion of the tetrapeptide, hydrolysis, isolation, and identification of the N-terminal amino acid as dansyl-alanine by comparison with standards using normal-phase TLC. A second portion of the tetrapeptide was hydrolyzed and the resulting four free amino acids were converted to their corresponding dansyl derivatives and purified by preparative normal-phase TLC. The three dansyl amino acids not identified previously were identified by TLC. The stereochemistry of each was determined by comparison with dansyl-dl-amino acid standards using reversed-phase TLC in the presence of ß-cyclodextrin, a chiral mobile phase additive. Finally, the correct amino acid sequence was determined by tandem quadrupole mass spectrometry. This project gives students valuable experience in microscale synthesis, both normal and reversed-phase TLC, stereochemical analysis, and mass spectrometry.

  9. A High-Performance Thin Layer Chromatography (HPTLC) Method for Simultaneous Determination of Diphenhydramine Hydrochloride and Naproxen Sodium in Tablets.

    Science.gov (United States)

    Bhole, R P; Shinde, S S; Chitlange, S S; Wankhede, S B

    2015-01-01

    A rapid and simple high-performance thin layer chromatography (HPTLC) method with densitometry at 230 nm was developed and validated for simultaneous determination of diphenhydramine hydrochloride (DPH) and naproxen sodium (NPS) from pharmaceutical preparation. The separation was carried out on aluminum plates precoated with silica gel 60 F254 using mobile phase toluene:methanol:glacial acetic acid (7.5:1:0.2, v/v/v). The linearity range lies between 200 and 1200 ng/band for DPH and 1760 and 10,560 ng/band for NPS with correlation coefficients of 0.994 and 0.995, respectively. The R f value for DPH is 0.20 ± 0.05 and for NPS is 0.61 ± 0.06. % Recoveries of DPH and NPS was in the range of 99.70%-99.95% and 99.63%-99.95%, respectively. Limit of detection value for DPH was 13.21 ng/band and for NPS was 8.03 ng/band. Limit of quantitation value for DPH was 40.06 ng/band and for NPS was 24.34 ng/band. The developed method was validated as per ICH guidelines. In stability testing, DPH was found unstable to acid and alkaline hydrolysis, and DPH and NPS were found unstable to oxidation, whereas both the drugs were stable to neutral and photodegradation. The proposed method was successfully applied for the routine quantitative analysis of dosage form containing DPH and NPS.

  10. Detection of adulterated copaiba (Copaifera multijuga Hayne oil-resins by refractive index and thin layer chromatography

    Directory of Open Access Journals (Sweden)

    Karol de S. Barbosa

    Full Text Available The refractive indices (RI of the eight samples of copaiba oils, collected for this study at RDS Tupé ranged from 1.50284 to 1.50786. The thin layer chromatography (TLC plates of these oils revealed with anisaldehyde-sulphuric acid reagent showed dark lilac stains with several small stains at low Rf and a large rounded stain at high Rf. On the other hand, the twelve copaiba oils purchased at local markets presented RI between 1.48176 and 1.50886, and the TLC plates, showed as general profile blue stains, with smaller superimposed stains at low Rf, bigger superimposed stains like elongated stain at high Rf and a colorless rounded stain at middle Rf. Among 12 purchased oils at local markets, a three oil-resins presented similar RI and TLC profile to those observed for collected copaiba oils; b six oils showed same RI and TLC profiles to those observed for soybean oil; c three samples presented RI near to those showed by copaiba oil-resin, however the TLC profile was near to profile observed for a prepared mixture soybean oil: copaiba oil, two samples with 3:1 proportion and one sample with 1:3 proportion. Therefore, the RI determination and the TLC profiles could be considered rapid and efficient procedures for detection of vegetal oil in the copaiba oil-resins.

  11. Pressurized planar electrochromatography, high-performance thin-layer chromatography and high-performance liquid chromatography--comparison of performance.

    Science.gov (United States)

    Płocharz, Paweł; Klimek-Turek, Anna; Dzido, Tadeusz H

    2010-07-16

    Kinetic performance, measured by plate height, of High-Performance Thin-Layer Chromatography (HPTLC), High-Performance Liquid Chromatography (HPLC) and Pressurized Planar Electrochromatography (PPEC) was compared for the systems with adsorbent of the HPTLC RP18W plate from Merck as the stationary phase and the mobile phase composed of acetonitrile and buffer solution. The HPLC column was packed with the adsorbent, which was scrapped from the chromatographic plate mentioned. An additional HPLC column was also packed with adsorbent of 5 microm particle diameter, C18 type silica based (LiChrosorb RP-18 from Merck). The dependence of plate height of both HPLC and PPEC separating systems on flow velocity of the mobile phase and on migration distance of the mobile phase in TLC system was presented applying test solute (prednisolone succinate). The highest performance, amongst systems investigated, was obtained for the PPEC system. The separation efficiency of the systems investigated in the paper was additionally confirmed by the separation of test component mixture composed of six hormones. 2010 Elsevier B.V. All rights reserved.

  12. Preparation of thin layer materials with macroporous microstructure for SOFC applications

    International Nuclear Information System (INIS)

    Marrero-Lopez, D.; Ruiz-Morales, J.C.; Pena-Martinez, J.; Canales-Vazquez, J.; Nunez, P.

    2008-01-01

    A facile and versatile method using polymethyl methacrylate (PMMA) microspheres as pore formers has been developed to prepare thin layer oxide materials with controlled macroporous microstructure. Several mixed oxides with fluorite and perovskite-type structures, i.e. doped zirconia, ceria, ferrites, manganites, and NiO-YSZ composites have been prepared and characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption and mercury porosimetry. The synthesised materials are nanocrystalline and present a homogeneous pore distribution and relatively high specific surface area, which makes them interesting for SOFC and catalysis applications in the intermediate temperature range. - Graphical abstract: Thin films materials of mixed oxides with potential application in SOFC devices have been prepared with macroporous microstructure using PMMA microspheres as pore formers. Display Omitted

  13. A simplified method for rapid quantification of intracellular nucleoside triphosphates by one-dimensional thin-layer chromatography

    DEFF Research Database (Denmark)

    Jendresen, Christian Bille; Kilstrup, Mogens; Martinussen, Jan

    2011-01-01

    -pyrophosphate (PRPP), and inorganic pyrophosphate (PPi) in cell extracts. The method uses one-dimensional thin-layer chromatography (TLC) and radiolabeled biological samples. Nucleotides are resolved at the level of ionic charge in an optimized acidic ammonium formate and chloride solvent, permitting...... quantification of NTPs. The method is significantly simpler and faster than both current two-dimensional methods and high-performance liquid chromatography (HPLC)-based procedures, allowing a higher throughput while common sources of inaccuracies and technical problems are avoided. For determination of PPi...

  14. Therapeutic drug monitoring of nevirapine in saliva in Uganda using high performance liquid chromatography and a low cost thin-layer chromatography technique

    NARCIS (Netherlands)

    Lamorde, M.; Fillekes, Q.; Sigaloff, K.; Kityo, C.; Buzibye, A.; Kayiwa, J.; Merry, C.; Nakatudde-Katumba, L.; Burger, D.M.; Wit, T.F. de

    2014-01-01

    BACKGROUND: In resource limited settings access to laboratory monitoring of HIV treatment is limited and therapeutic drug monitoring is generally unavailable. This study aimed to evaluate nevirapine concentrations in saliva using low-cost thin-layer chromatography (TLC) and nevirapine concentrations

  15. Therapeutic drug monitoring of nevirapine in saliva in Uganda using high performance liquid chromatography and a low cost thin-layer chromatography technique

    NARCIS (Netherlands)

    Lamorde, Mohammed; Fillekes, Quirine; Sigaloff, Kim; Kityo, Cissy; Buzibye, Allan; Kayiwa, Joshua; Merry, Concepta; Nakatudde-Katumba, Lillian; Burger, David; Rinke de Wit, Tobias F.

    2014-01-01

    In resource limited settings access to laboratory monitoring of HIV treatment is limited and therapeutic drug monitoring is generally unavailable. This study aimed to evaluate nevirapine concentrations in saliva using low-cost thin-layer chromatography (TLC) and nevirapine concentrations in plasma

  16. Separation of pigment formulations by high-performance thin-layer chromatography with automated multiple development.

    Science.gov (United States)

    Stiefel, Constanze; Dietzel, Sylvia; Endress, Marc; Morlock, Gertrud E

    2016-09-02

    Food packaging is designed to provide sufficient protection for the respective filling, legally binding information for the consumers like nutritional facts or filling information, and an attractive appearance to promote the sale. For quality and safety of the package, a regular quality control of the used printing materials is necessary to get consistently good print results, to avoid migration of undesired ink components into the food and to identify potentially faulty ink batches. Analytical approaches, however, have hardly been considered for quality assurance so far due to the lack of robust, suitable methods for the analysis of rarely soluble pigment formulations. Thus, a simple and generic high-performance thin-layer chromatography (HPTLC) method for the separation of different colored pigment formulations was developed on HPTLC plates silica gel 60 by automated multiple development. The gradient system provided a sharp resolution for differently soluble pigment constituents like additives and coating materials. The results of multi-detection allowed a first assignment of the differently detectable bands to particular chemical substance classes (e.g., lipophilic components), enabled the comparison of different commercially available pigment batches and revealed substantial variations in the composition of the batches. Hyphenation of HPTLC with high resolution mass spectrometry and infrared spectroscopy allowed the characterization of single unknown pigment constituents, which may partly be responsible for known quality problems during printing. The newly developed, precise and selective HPTLC method can be used as part of routine quality control for both, incoming pigment batches and monitoring of internal pigment production processes, to secure a consistent pigment composition resulting in consistent ink quality, a faultless print image and safe products. Hyphenation of HPTLC with the A. fischeri bioassay gave first information on the bioactivity or rather

  17. Purification of 3H-dihydroalprenolol by two dimensional thin layer chromatography

    International Nuclear Information System (INIS)

    Smisterova, J.; Soltes, L.; Kallay, Z.

    1989-01-01

    A two dimensional thin-layer chromatographic method was developed for the purification and analysis of (-)-[ 3 H]dihydroalprenolol by using an acidic mobile phase (butanol/water/acetic acid 25:10:4, v/v) in one direction and a basic eluent (chloroform/acetone/triethylamine 50:40:10, v/v) in another direction. (author)

  18. Application of RF correction in thin-layer chromatography by means of two reference RF values

    NARCIS (Netherlands)

    Dhont, J.H.; Vinkenborg, C.; Compaan, H.; Ritter, F.J.; Labadie, R.P.; Verweij, A.; Zeeuw, R.A. de

    1972-01-01

    Results of the inter-laboratory experiment described in this paper show that the GALANOS AND KAPOULAS equation can be applied satisfactorily to correct RF values obtained on thin-layer chromatograms in a polar multi-component solvent. Addition of Kieselguhr to the silica gel gives RFc values

  19. Investigation of Symphytum cordatum alkaloids by liquid-liquid partitioning, thin-layer chromatography and liquid chromatography-ion-trap mass spectrometry

    International Nuclear Information System (INIS)

    Mroczek, Tomasz; Ndjoko-Ioset, Karine; Glowniak, Kazimierz; Mietkiewicz-Capala, Agnieszka; Hostettmann, Kurt

    2006-01-01

    From the alkalised crude extract of Symphytum cordatum (L.) W.K. roots, pyrrolizidine alkaloids (PAs) were extracted as free tertiary bases and polar N-oxides in a merely one-step liquid-liquid partitioning (LLP) in separation funnel and subsequently pre-fractionated by preparative multiple-development (MD) thin-layer chromatography (TLC) on silica gel plates. In this way three alkaloid fractions of different polarities and retention on silica gel plates were obtained as: the most polar N-oxides of the highest retention, the tertiary bases of medium retention, and diesterified N-oxides of the lowest retention. The former fraction was reduced into free bases by sodium hydrosulfite and purified by LLP on Extrelut-NT3 cartridge. It was further analysed together with the two other fractions by high-performance liquid chromatography (HPLC)-ion-trap mass spectrometry with atmospheric pressure chemical ionization (APCI) interface on XTerra C 18 column using a gradient elution. Based on MS n spectra, 18 various alkaloids have been tentatively determined for the first time in this plant as the following types of structure: echimidine-N-oxide (three diasteroisomers), 7-sarracinyl-9-viridiflorylretronecine (two diasteroisomers), echimidine (two diasteroisomers), lycopsamine (two diasteroisomers), dihydroechinatine-N-oxide, dihydroheliospathuline-N-oxide, lycopsamine-N-oxide (three diasteroisomers), 7-acetyllycopsamine-N-oxide, symphytine-N-oxide (two diasteroisomers) and 2'',3''-epoxyechiumine-N-oxide

  20. Investigation of Symphytum cordatum alkaloids by liquid-liquid partitioning, thin-layer chromatography and liquid chromatography-ion-trap mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Mroczek, Tomasz [Department of Pharmacognosy with Medicinal Plants Laboratory, Medical University, 1 Chodzki St., 20-093 Lublin (Poland)]. E-mail: tmroczek@pharmacognosy.org; Ndjoko-Ioset, Karine [Laboratoire de Pharmacognosie et Phytochimie, Ecole de Pharmacie Geneve-Lausanne, Universite de Geneve, Quai Ernest-Ansermet 30, CH-1211 Geneva 4 (Switzerland); Glowniak, Kazimierz [Department of Pharmacognosy with Medicinal Plants Laboratory, Medical University, 1 Chodzki St., 20-093 Lublin (Poland); Mietkiewicz-Capala, Agnieszka [Department of Pharmacognosy with Medicinal Plants Laboratory, Medical University, 1 Chodzki St., 20-093 Lublin (Poland); Hostettmann, Kurt [Laboratoire de Pharmacognosie et Phytochimie, Ecole de Pharmacie Geneve-Lausanne, Universite de Geneve, Quai Ernest-Ansermet 30, CH-1211 Geneva 4 (Switzerland)

    2006-05-04

    From the alkalised crude extract of Symphytum cordatum (L.) W.K. roots, pyrrolizidine alkaloids (PAs) were extracted as free tertiary bases and polar N-oxides in a merely one-step liquid-liquid partitioning (LLP) in separation funnel and subsequently pre-fractionated by preparative multiple-development (MD) thin-layer chromatography (TLC) on silica gel plates. In this way three alkaloid fractions of different polarities and retention on silica gel plates were obtained as: the most polar N-oxides of the highest retention, the tertiary bases of medium retention, and diesterified N-oxides of the lowest retention. The former fraction was reduced into free bases by sodium hydrosulfite and purified by LLP on Extrelut-NT3 cartridge. It was further analysed together with the two other fractions by high-performance liquid chromatography (HPLC)-ion-trap mass spectrometry with atmospheric pressure chemical ionization (APCI) interface on XTerra C{sub 18} column using a gradient elution. Based on MS {sup n} spectra, 18 various alkaloids have been tentatively determined for the first time in this plant as the following types of structure: echimidine-N-oxide (three diasteroisomers), 7-sarracinyl-9-viridiflorylretronecine (two diasteroisomers), echimidine (two diasteroisomers), lycopsamine (two diasteroisomers), dihydroechinatine-N-oxide, dihydroheliospathuline-N-oxide, lycopsamine-N-oxide (three diasteroisomers), 7-acetyllycopsamine-N-oxide, symphytine-N-oxide (two diasteroisomers) and 2'',3''-epoxyechiumine-N-oxide.

  1. Thin layer chromatography of glucose and sorbitol on Cu(II)-impregnated silica gel plates

    Energy Technology Data Exchange (ETDEWEB)

    Hadzija, O. (Ruder Boskovic Inst., Zagreb (Croatia)); Spoljar, B. (Ruder Boskovic Inst., Zagreb (Croatia)); Sesartic, L. (Inst. of Immunology, Zagreb (Croatia))

    1994-04-01

    A thin-layer chromatographic (TLC) separation of glucose and sorbitol on CU(II)-impregnated silica gel plates with n-propanol: Water (4:1) v/v as developer and potassium permanganate as detecting reagent has been worked out. The new impregnant is completely insoluble in water and thus enables the use of an aqueous developer. The R[sub f]-values are 55 and 10 for glucose and sorbitol, respectively. (orig.)

  2. Rapid, simple, and highly sensitive analysis of drugs in biological samples using thin-layer chromatography coupled with matrix-assisted laser desorption/ionization mass spectrometry.

    Science.gov (United States)

    Kuwayama, Kenji; Tsujikawa, Kenji; Miyaguchi, Hajime; Kanamori, Tatsuyuki; Iwata, Yuko T; Inoue, Hiroyuki

    2012-01-01

    Rapid and precise identification of toxic substances is necessary for urgent diagnosis and treatment of poisoning cases and for establishing the cause of death in postmortem examinations. However, identification of compounds in biological samples using gas chromatography and liquid chromatography coupled with mass spectrometry entails time-consuming and labor-intensive sample preparations. In this study, we examined a simple preparation and highly sensitive analysis of drugs in biological samples such as urine, plasma, and organs using thin-layer chromatography coupled with matrix-assisted laser desorption/ionization mass spectrometry (TLC/MALDI/MS). When the urine containing 3,4-methylenedioxymethamphetamine (MDMA) without sample dilution was spotted on a thin-layer chromatography (TLC) plate and was analyzed by TLC/MALDI/MS, the detection limit of the MDMA spot was 0.05 ng/spot. The value was the same as that in aqueous solution spotted on a stainless steel plate. All the 11 psychotropic compounds tested (MDMA, 4-hydroxy-3-methoxymethamphetamine, 3,4-methylenedioxyamphetamine, methamphetamine, p-hydroxymethamphetamine, amphetamine, ketamine, caffeine, chlorpromazine, triazolam, and morphine) on a TLC plate were detected at levels of 0.05-5 ng, and the type (layer thickness and fluorescence) of TLC plate did not affect detection sensitivity. In addition, when rat liver homogenate obtained after MDMA administration (10 mg/kg) was spotted on a TLC plate, MDMA and its main metabolites were identified using TLC/MALDI/MS, and the spots on a TLC plate were visualized by MALDI/imaging MS. The total analytical time from spotting of intact biological samples to the output of analytical results was within 30 min. TLC/MALDI/MS enabled rapid, simple, and highly sensitive analysis of drugs from intact biological samples and crude extracts. Accordingly, this method could be applied to rapid drug screening and precise identification of toxic substances in poisoning cases and

  3. Simple Identification of the Neutral Chlorinated Auxin in Pea by Thin Layer Chromatography

    DEFF Research Database (Denmark)

    Engvild, Kjeld Christensen

    1980-01-01

    to small volumes and chromatographed in CHCl3 or CCl4 solvent systems separating the chlorinated auxin from indoleacetonitrile and the methyl or ethyl esters of indoleacetic acid. Colour reaction was carried out with some of the Salkowski FeCl3 sprays of which Ehmann's FeCl3/dimethylaminobenzaldehyde......One of the neutral chlorinated auxins of immature pea seeds was readily identified by thin layer procedures simple enough to serve in student's laboratory courses. 4-Chloroindole-3-acetic acid methyl ester was extracted from 50 g of commercial, frozen peas by either water or acetone, concentrated...

  4. Variables affecting resolution of lung phospholipids in one-dimensional thin-layer chromatography.

    Science.gov (United States)

    Krahn, J

    1987-01-01

    Resolution of the confusion in the literature about the separation of lung phospholipids in thin-layer chromatographic systems has awaited a systematic study of the variables that potentially affect this separation. In this study I show that: incorporation of ammonium sulfate into silica gel "GHL" has a dramatic effect on separation of lung phospholipids; this effect is equally dramatic but different in activated and nonactivated gels; when it picks up moisture, ammonium sulfate-activated gel very rapidly loses its ability to resolve lecithin from phosphatidylinositol; in gel containing ammonium sulfate, small amounts of phosphatidylethanolamine are hydrolyzed to lyso-phosphatidylethanolamine.

  5. Quantification of Quercetin and Rutin from Benincasa hispida Seeds and Carissa Congesta Roots by High-performance Thin Layer Chromatography and High-performance Liquid Chromatography.

    Science.gov (United States)

    Doshi, Gaurav Mahesh; Une, Hemant Devidas

    2016-01-01

    In Indian Ayurvedic system, Benincasa hispida (BH) and Carissa congesta (CC) are well-known plants used for major and minor ailments. BH has been regarded as Kushmanda, whereas CC has been used in immune-related disorders of the human system. Quercetin and rutin identified from the vast plethora of plant extracts have proved to possess ethnopharmacological relevance. In present studies, we have determined quercetin and rutin in terms of percentage in BH seeds and CC roots by high-performance thin layer chromatography (HPTLC) and high-performance liquid chromatography (HPLC). After extraction and phytochemical screening, the extracts were subjected to quantification for the presence of quercetin and rutin by HPTLC and HPLC. HPTLC showed quercetin as 44.60, 27.13% and rutin as 32.00, 36.31% w/w, whereas HPLC revealed quercetin as 34.00, 35.00% and rutin as 21.99, 45.03% w/v in BH and CC extracts, respectively. The BH and CC extracts have elucidated peaks that were corresponding with standard peaks on undertaking chromatographic studies. Quercetin and rutin are isolated from BH seeds and CC roots by High Performance. Thin Layer Chromatography and High Performance Liquid Chromatography. HPTLC revealed presence of quercetin as 44.60, 27.13 % and rutin as 32.00, 36.31 % w/w. HPLC revealed presence of quercetin as 34.00, 35.00 % and rutin as 21.99, 45.03 % w/v. Abbreviation Used: HPTLC: High Performance Thin Layer Chromatography; HPLC: High Pressure Liquid Chromatography, UV: Ultraviolet, CC: Carissa congesta, BH: Benincasa hispida.

  6. Quantification of Quercetin and Rutin from Benincasa hispida Seeds and Carissa Congesta Roots by High-performance Thin Layer Chromatography and High-performance Liquid Chromatography

    Science.gov (United States)

    Doshi, Gaurav Mahesh; Une, Hemant Devidas

    2016-01-01

    Objective: In Indian Ayurvedic system, Benincasa hispida (BH) and Carissa congesta (CC) are well-known plants used for major and minor ailments. BH has been regarded as Kushmanda, whereas CC has been used in immune-related disorders of the human system. Quercetin and rutin identified from the vast plethora of plant extracts have proved to possess ethnopharmacological relevance. Materials and Methods: In present studies, we have determined quercetin and rutin in terms of percentage in BH seeds and CC roots by high-performance thin layer chromatography (HPTLC) and high-performance liquid chromatography (HPLC). After extraction and phytochemical screening, the extracts were subjected to quantification for the presence of quercetin and rutin by HPTLC and HPLC. Results: HPTLC showed quercetin as 44.60, 27.13% and rutin as 32.00, 36.31% w/w, whereas HPLC revealed quercetin as 34.00, 35.00% and rutin as 21.99, 45.03% w/v in BH and CC extracts, respectively. Conclusion: The BH and CC extracts have elucidated peaks that were corresponding with standard peaks on undertaking chromatographic studies. SUMMARY Quercetin and rutin are isolated from BH seeds and CC roots by High Performance. Thin Layer Chromatography and High Performance Liquid Chromatography. HPTLC revealed presence of quercetin as 44.60, 27.13 % and rutin as 32.00, 36.31 % w/w. HPLC revealed presence of quercetin as 34.00, 35.00 % and rutin as 21.99, 45.03 % w/v. Abbreviation Used: HPTLC: High Performance Thin Layer Chromatography; HPLC: High Pressure Liquid Chromatography, UV: Ultraviolet, CC: Carissa congesta, BH: Benincasa hispida PMID:26941534

  7. Composite glycerol/graphite/aromatic acid matrices for thin-layer chromatography/matrix-assisted laser desorption/ionization mass spectrometry of heterocyclic compounds.

    Science.gov (United States)

    Esparza, Cesar; Borisov, R S; Varlamov, A V; Zaikin, V G

    2016-10-28

    New composite matrices have been suggested for the analysis of mixtures of different synthetic organic compounds (N-containing heterocycles and erectile dysfunction drugs) by thin layer chromatography/matrix-assisted laser desorption ionization time-of-flight mass spectrometry (TLC/MALDI-TOF). Different mixtures of classical MALDI matrices and graphite particles dispersed in glycerol were used for the registration of MALDI mass spectra directly from TLC plates after analytes separation. In most of cases, the mass spectra possessed [M+H] + ions; however, for some analytes only [M+Na] + and [M+K] + ions were observed. These ions have been used to generate visualized TLC chromatograms. The described approach increases the desorption/ionization efficiencies of analytes separated by TLC, prevent spot blurring, simplifies and decrease time for sample preparation. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Monitoring of monooctanoyl phosphatidylcholine synthesis by enzymatic acidolysis between soybean phosphatidylcholine and caprylic acid by thin-layer chromatography with a flame ionization detector

    DEFF Research Database (Denmark)

    Vikbjerg, Anders Falk; Mu, Huiling; Xu, Xuebing

    2005-01-01

    Thin-layer chromatography with flame ionization detector (TLC-FID) method was used for monitoring the production of structured phospholipids (ML-type: L-long chain fatty acids; M-medium chain fatty acids) by enzyme-catalyzed acidolysis between soybean phosphatidylcholine (PC) and caprylic acid....... It was found that the structured PC fractionated into 2-3 distinct bands on both plate thin layer chromatography (TLC) and Chromarod TLC. These 3 bands represented PC of LL-type, ML-type and MM-type, respectively. The TLC-FID method was applied in the present study to examine the influence of enzyme dosage...

  9. Use of two-phase aqueous systems based on water-soluble polymers in thin-layer and extraction chromatography for recovery and separtion of actinides

    International Nuclear Information System (INIS)

    Molochnikova, N.P.; Shkinev, V.M.; Myasoedov, B.F.

    1995-01-01

    The feasibility has been demonstrated of using two-phase aqueous systems based on water-soluble polymers, polyethylene glycol and dextran sulfate, in thin-layer and extraction chromatography for recovery and separation of actinides. A convenient method has been proposed for continuous recovery of 239 Np from 243 Am, originating from differences in sorption of tri- and pentavalent actinides from sulfate solutions containing potassium phosphotungstate by silica gel impregnated with polyethylene glycol. New plates for thin-layer chromatography using water-soluble polymers have been developed. These plates were used to study behavior of americium in various oxidation states in thin sorbent layers

  10. Determination of aflatoxins B1 and M1 in animal feeds and liquid milk using thin layer chromatography

    International Nuclear Information System (INIS)

    Njue, W.; Gitu, L.; Kaberia, F.

    1996-01-01

    Animal feed samples were collected from feeding troughs and analysed for levels of aflatoxins B 1 , a toxic and carcinogenic mycotoxin. When aflatoxin B 1 is consumed by dairy cattle some of it is hydroxylated to form aflatoxin M 1 , which can appear in milk. Since aflatoxin M 1 , is also toxic and carcinogenic, it was determined in liquid milk. The determinations were carried out using thin-layer chromatography. Some of the feed samples were found to contain concentrations of aflatoxin B 1 that were above maximum tolerated values in foods and feeds in various countries. Brewers grain and used poultry feed contained 133.4 ppb, while the barley husks had a maximum value of 27.4 ppb. The details of the experimental results and analytical methods used are presented.(author)

  11. Larvicidal Effect of Vinca Fruit Extract (Vinca rosea Against Aedes aegypti Larvae and Secondary Metabolites Profile by Thin Layer Chromatography

    Directory of Open Access Journals (Sweden)

    Rahmawati Ekaputri

    2014-04-01

    Full Text Available Background: Vinca rosea is known contain alkaloids, it was usually used to treat various diseases. Alkaloids from Vinca leaves are also already known have larvicidal activity. Based on this toxicological activity, the fruit of Vinca rosea was selected to investigation its larvicidal activity against the 3rd instar larvae of the mosquito vector of dengue haemorrhagic fever (DHF Aedes aegypti.  Five concentrations of Vinca fruit extract were tested against the 3rd instar Aedes aegypti larvae. The different larval mortality percentages were recorded after 24 hours. Lethal concentration (LC50 anf LC90 of Vinca fruit extract were calculated using Probit analysis. Phytochemical compounds  of ethanolic extract also investigated using Thin layer Chromatography (TLC. LC50 and LC90 values of fruit extract were 2.987 mg/ml and 32.861 mg/ml. Alkaloids were detected in extract.

  12. The characterization of petroleum and creosote-contaminated soils: Class component analysis by thin layer chromatography with flame ionization detection

    International Nuclear Information System (INIS)

    Pollard, S.J.T.; Hrudey, S.E.; Fuhr, B.J.; Alex, R.F.; Holloway, L.R.

    1992-01-01

    The assessment and reclamation of coal tar, creosote and petroleum-contaminated sites is emerging as a major challenge to industry and the federal and provincial Canadian governments. Contaminants frequently include polynuclear aromatic compounds (PAH), several high molecular weight analogues of which are documented carcinogens. Adaptation of thin layer chromatography with flame ionization detection for the analysis of hydrocarbon-contaminated soils is described. The method is directly applicable to the analysis of oily waste extracts from petroleum and creosote wood preservative site soils and is capable of distinguishing between the saturate, aromatic and polar components of waste residues. The method provides a rapid, low cost class component analysis of heavy hydrocarbon waste extracts and is particularly useful for estimating the extent of weathering experienced by chronically exposed hydrocarbon wastes in the soil environment. As such, it is useful as a screening tool for a preliminary assessment of the biotreatability or inherent recalcitrance of hydrocarbon waste mixtures. 11 refs., 5 figs

  13. Separation of metals in the form of ion associates by the method of thin-layer chromatography

    International Nuclear Information System (INIS)

    Shapovalova, E.N.; Timerbaev, A.R.; Bol'shova, T.A.; Mel'nik, S.V.; Kordejro, E.

    1990-01-01

    Behaviour of pyridylazo resorcinates of certain metals (Ga, In, Fe, Co) in the form of ionic pairs with tri-n-octylamine (TOA) under conditions of thin-layer chromatography (TLC) has been studied. For all eluents investigated Ga and In complexes possess the highest mobility. Selectivity of ionic associate separation decreases with an increase in mobile phase polarity. Mixtures with 10-15 % content of isopropanol in eluating solution are the optimal ones. Separation of Ga and In from Fe 3+ and Co takes place with separation criterion 3.1 and 4.1 respectively. An attempt to separate ionic associates of In and Ga failed owing to similar stability of their pyridylazoresorcinates. Solution of the problem of In and Ga determination in the presence of iron can contribute to concrete application of the method

  14. Using of scanner on the evaluation of pesticides mobility by thin-layer chromatography

    International Nuclear Information System (INIS)

    Tornisielo, V.L.; Costa, M.A.; Furlan, G.R.

    1995-01-01

    Knowledge of pesticide leaching potential is an essential information to preview environmental fate. The experiment confirms the possibility of using radiochromatogram scanning as a substitute for X-ray autoradiography, when Thin Layer Chromatografy (TLC) methodogy is used to determine mobility of a pesticide. Three types of soil from Sao Paulo state and five herbicides (metolachlor, asulan, simazing, 2,4-D and trifluralin), labeled with 14 C, were used. The radiochromatogram scanners permits a quick detection of the position of the radioactive spots to determine the Rf for each pesticide, while X-ray film has to be placed on the plate on the dark room for several days or weeks and then developed to detect spots, subsequently measure and calculate Rf. The results showed that the evaluation by scanner and X-ray were similar. Hence we conclude that the use of the scanner should be considered since this methodology is faster and as accurate as the X-ray methodology. (author). 4 refs, 1 fig, 2 tabs

  15. Peak broadening in paper chromatography and related techniques VI. The efficiency of various kinds of chromatography paper and thin-layer cellulose powder for the separation of amino acids

    NARCIS (Netherlands)

    Ligny, C.L. de; Kok, E.C.M.

    1968-01-01

    The efficiency of several chromatography papers and thin-layer cellulose powders for the separation of amino acids is investigated, using the minimum elution time for a given resolution as the criterion.

  16. Phosphorolytic activity of Escherichia coli glycyl-tRNA synthetase towards its cognate aminoacyl adenylate detected by 31P-NMR spectroscopy and thin-layer chromatography

    DEFF Research Database (Denmark)

    Led, Jens Jørgen; Switon, Werner K.; Jensen, Kaj Frank

    1983-01-01

    The catalytic activity of highly purified Escherichia coli glycyl-tRNA synthetase has been studied by 31P-NMR spectroscopy and thin-layer chromatography on poly(ethyleneimine)-cellulose. It was found that this synthetase, besides the activation of its cognate amino acid and the syntheses...

  17. Validation of an analytical method for the determination of spiramycin, virginiamycin and tylosin in feeding-stuffs bij thin-layer chromatography and bio-autography

    NARCIS (Netherlands)

    Vincent, U.; Gizzi, G.; Holst, von C.; Jong, de J.; Michard, J.

    2007-01-01

    An inter-laboratory validation was carried out to determine the performance characteristics of an analytical method based on thin-layer chromatography (TLC) coupled to microbiological detection (bio-autography) for screening feed samples for the presence of spiramycin, tylosin and virginiamycin.

  18. Role of thin-layer chromatography in ascertaining Kashaya Rasa (astringent taste) in medicinal plants on the concept of Samana and Vichitra Pratyayarabdha principles of Ayurveda.

    Science.gov (United States)

    Kolhe, Rasika H; Acharya, Rabinarayan; Shukla, Vinay J

    2014-04-01

    Pharmacodynamics, in Ayurveda has been described in terms of Rasadipanchaka. Rasa, on one side indicates the Bhautika composition of the drug and on the other side predicts the action. Different analytical techniques, pharmaceutical processes are being used in Ayurveda for the purpose of standardization of raw drugs. In this study an attempt has been made to apply chromatographic technique in determination of Kashaya (astringent) Rasa (taste). Two important Kashaya dominant drugs Kulattha (Dolichos biflorus Linn.) and Kanchanara (Bauhinia variegata Linn.), falling under Vichitra and Samana Pratyayarabdha category respectively, were subjected to physicochemical parameters and qualitative tests followed by High-Performance Thin-Layer Chromatography (HPTLC). In light of chromatographic fingerprinting; sample preparation protocol is modified to incorporate taste threshold in correlation. Column chromatography is used for first-level discrimination technique followed by HPTLC. Kashaya Rasa Dominant Zone (KsRDZ) was separated and subjected to TLC fingerprinting. The KsRDZ fraction was designated as Botanical Reference Material (BRM) in further analysis. Ash value, Alcohol and water soluble extract value were more in B variegata as compared to D biflorus. Presence of tannin in both the samples was confirmed through qualitative test. The KsRDZ fraction separated at Rf 0.46 and 0.48 for Kulattha and Kanchanara respectively. The results showed that the planner chromatography technique seems very useful when BRM hypothesis was adjunct to method that explains the categorization according to traditional Rasa domain classification method.

  19. Method development for Lawsone estimation in Trichup herbal hair powder by high-performance thin layer chromatography

    Directory of Open Access Journals (Sweden)

    Maunang M Patel

    2013-01-01

    Full Text Available A simple, specific, accurate, precise and robust high-performance thin-layer chromatographic method has been developed and validated for estimation of Lawsone in Trichup herbal hair powder (coded as a THHP, polyherbal formulation. The chromatographic development was carried out on aluminum plates pre-coated with silica gel 60F 254 and good resolution was achieved with Toluene: Ethyl acetate: Glacial acetic acid (8:1:1 v/v/v as mobile phase. Lawsone detection was carried out densitometrically at 277 nm and obtained retardation factor value was 0.46 ± 0.02. The method was validated with respect to specificity, linearity, accuracy, precision and robustness. The calibration curve was achieved to be linear over a range of 5-60 μg/ml and regression coefficient was obtained 0.998. Accuracy of chromatographic method was evaluated by standard addition method; recovery was obtained 99.25 ± 0.61% . The peak purity of Lawsone was achieved 0.999 r. Relative standard deviation for intraday and inter-day precision was 0.37-0.56% and 0.42-0.55%, respectively. The limit of detection and limit of quantification of the Lawsone were found to be 1.08 μg/m land 3.28 μg/ml, respectively. This result shows that the method was well validated. In the present study, the Lawsone content was found 0.322 ± 0.014% in THHP. This study reveals that the proposed high performance thin layer chromatography method is accurate, fast and cost- effective for routine estimation of Lawsone in polyherbal formulation.

  20. Marker based standardization of polyherbal formulation (SJT-DI-02 by high performance thin layer chromatography method

    Directory of Open Access Journals (Sweden)

    Bhakti J Ladva

    2014-01-01

    purity of the bands due to marker compounds in the sample extracts were confirmed by overlaying the absorption spectra recorded at start, middle and end position of the band in the sample tracks. After conforming all these things fingerprints were developed for all three formulations which will be act as authentification and quality control tool. Results: % w/w of asarones is 3.61, % w/w of marmelosin is 4.60, % w/w of gallic acid is 10.80 and % w/w of lupeol is 4.13.The method was validated in terms of linearity, precision, repeatability, limit of detection, limit of quantification and accuracy. In well-developed mobile phase system linearity was found to be in the range of 0.983-0.995, % recovery was found to be in the range of 97.48-99.63, % RSD for intraday and interday was found to be 0.13- 0.70 and 0.32 -1.41 and LOD and LOQ was found to be in the range of 0.15- 0.61 and 0.45 -1.83 microgram per ml. Conclusion: Thus High performance thin layer chromatography (HPTLC methods were developed and validated in terms of linearity, precision, repeatability, limit of detection, limit of quantification and accuracy. The methods were rapid, sensitive, reproducible and economical. It does not suffer any positive or negative interference due to common other component present in the formulation and would also serve as a tool for authentication of herbal products containing marmelosin, gallic acid, lupeol and asarones. Thus this work provides standardized and therapeutically active polyherbal formulations for the different ailments.

  1. Assessment of aflatoxin B1 in livestock feed and feed ingredients by high-performance thin layer chromatography

    Directory of Open Access Journals (Sweden)

    Korrapati Kotinagu

    2015-12-01

    Full Text Available Aim: Detection of aflatoxin B1 in Livestock compound Feed and feed ingredients by high-performance thin layer chromatography (HPTLC. Materials and Methods: Chromatography was performed on HPTLC silica gel 60 F 254, aluminum sheets by CAMAG automatic TLC sampler 4, with mobile phase condition chloroform:acetone:water (28:4:0.06. Extraction of aflatoxin B1 from samples was done as per AOAC method and screening and quantification done by HPTLC Scanner 4 under wavelength 366 nm. Results: A total of 97 livestock feed (48 and feed ingredients (49 samples received from different livestock farms and farmers were analyzed for aflatoxin B1of which 29 samples were contaminated, constituting 30%. Out of 48 livestock compound feed samples, aflatoxin B1 could be detected in 16 samples representing 33%, whereas in livestock feed ingredients out of 49 samples, 13 found positive for aflatoxin B1 representing 24.5%. Conclusion: HPTLC assures good recovery, precision, and linearity in the quantitative determination of aflatoxin B1 extracted from Livestock compound feed and feed ingredients. As more number of feed and feed ingredients are contaminated with aflatoxin B1 which causes deleterious effects in both animal and human beings, so there is a need for identifying the source of contamination, executing control measures, enabling better risk assessment techniques, and providing economic benefits.

  2. Combined thin layer chromatography and gas chromatography with mass spectrometric analysis of lipid classes and fatty acids in malnourished polar bears (Ursus maritimus) which swam to Iceland.

    Science.gov (United States)

    Eibler, Dorothee; Krüger, Sabine; Skírnisson, Karl; Vetter, Walter

    2017-03-01

    Between 2008 and 2011, four polar bears (Ursus maritimus) from the Greenland population swam and/or drifted on ice to Iceland where they arrived in very poor body condition. Body fat resources in these animals were only between 0% and 10% of the body weight (usually 25%). Here we studied the lipid composition in different tissues (adipose tissue if available, liver, kidney and muscle). Lipid classes were determined by thin layer chromatography (TLC) and on-column gas chromatography with mass spectrometry (GC/MS). The fatty acid pattern of total lipids and free fatty acids was analyzed by GC/MS in selected ion monitoring (SIM) mode. Additionally, cholesteryl esters and native fatty acid methyl esters, initially detected as zones in thin layer chromatograms, were enriched by solid phase extraction and quantified by GC/MS. The ratio of free fatty acids to native fatty acid methyl esters could be correlated with the remained body lipids in the polar bears and thus may also serve as a marker for other starving animals or even for humans. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. The reciprocal iso-inhibition volume concept: A procedure for the evaluation in effect-directed analysis with thin-layer chromatography - using the thin-layer chromatography-luminescent bacteria assay as an example.

    Science.gov (United States)

    Schulz, Wolfgang; Weiss, Stefan C; Weber, Walter H; Winzenbacher, Rudi

    2017-10-13

    In effect-directed analysis (EDA) with high-performance thin-layer chromatography (HPTLC), the effect is often detected using images. Thus, an approach to create inhibition chromatograms from these images was developed using the example of the HPTLC- bioluminescence inhibition test. A comparison between the cuvette test and the HPTLC test shows that the test on the plate is significantly more sensitive. To describe the strength of the effect, the EC 50 value is determined from the dose-response relationship. However, the inhibiting compounds are generally unknown and thus their concentrations are also unknown. Therefore, instead of the concentration, the known application volumes are used. This enables the calculation of the application volume necessary to achieve 50% inhibition. Since the volume is inversely proportional to the concentration, the reciprocal value of the calculated volume is indicated and is referred to as the reciprocal iso-inhibition volume (RIV). Using this RIV-concept, it is now possible to compare inhibition bands within and between plates. The entire evaluation is described by the means of two samples from a contaminated site using the bioluminescence inhibition. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Characterization of E 471 food emulsifiers by high-performance thin-layer chromatography-fluorescence detection.

    Science.gov (United States)

    Oellig, Claudia; Brändle, Klara; Schwack, Wolfgang

    2018-07-13

    Mono- and diacylglycerol (MAG and DAG) emulsifiers, also known as food additive E 471, are widely used to adjust techno-functional properties in various foods. Besides MAGs and DAGs, E 471 emulsifiers additionally comprise different amounts of triacylglycerols (TAGs) and free fatty acids (FFAs). MAGs, DAGs, TAGs and FFAs are generally determined by high-performance liquid chromatography (HPLC) or gas chromatography (GC) coupled to mass selective detection, analyzing the individual representatives of the lipid classes. In this work we present a rapid and sensitive method for the determination of MAGs, DAGs, TAGs and FFAs in E 471 emulsifiers by high-performance thin-layer chromatography with fluorescence detection (HPTLC-FLD), including a response factor system for quantitation. Samples were simply dissolved and diluted with t-butyl methyl ether before a two-fold development was performed on primuline pre-impregnated LiChrospher silica gel plates with diethyl ether and n-pentane/n-hexane/diethyl ether (52:20:28, v/v/v) as the mobile phases to 18 and 75 mm, respectively. For quantitation, the plate was scanned in the fluorescence mode at UV 366/>400 nm, when the cumulative signal for each lipid class was used. Calibration was done with 1,2-distearin and amounts of lipid classes were calculated with response factors and expressed as monostearin, distearin, tristearin and stearic acid. Limits of detection and quantitation were 1 and 4 ng/zone, respectively, for 1,2-distearin. Thus, the HPTLC-FLD approach represents a simple, rapid and convenient screening alternative to HPLC and GC analysis of the individual compounds. Visual detection additionally enables an easy characterization and the direct comparison of emulsifiers through the lipid class pattern, when utilized as a fingerprint. Copyright © 2018 Elsevier B.V. All rights reserved.

  5. Forensic Analysis of Blue Ball point Pen Inks on Questioned Documents by High Performance Thin Layer Chromatography Technique (HPTLC)

    International Nuclear Information System (INIS)

    Lee, L.C.; Siti Mariam Nunurung; Abdul Aziz Ishak

    2014-01-01

    Nowadays, crimes related to forged documents are increasing. Any erasure, addition or modification in the document content always involves the use of writing instrument such as ball point pens. Hence, there is an evident need to develop a fast and accurate ink analysis protocol to solve this problem. This study is aimed to determine the discrimination power of high performance thin layer chromatography (HPTLC) technique for analyzing a set of blue ball point pen inks. Ink samples deposited on paper were extracted using methanol and separated via a solvent mixture of ethyl acetate, methanol and distilled water (70: 35: 30, v/ v/ v). In this method, the discrimination power of 89.40 % was achieved, which confirm that the proposed method was able to differentiate a significant number of pen-pair samples. In addition, composition of blue pen inks was found to be homogeneous (RSD < 2.5 %) and the proposed method showed good repeatability and reproducibility (RSD < 3. 0%). As a conclusion, HPTLC is an effective tool to separate blue ball point pen inks. (author)

  6. A novel high-performance thin layer chromatography method for quantification of long chain aliphatic hydrocarbons from Cissus quadrangularis

    Directory of Open Access Journals (Sweden)

    Vandana Jain

    2016-08-01

    Full Text Available Context: A high-performance thin layer chromatography (HPTLC is an analytical technique, which can be used for the determination of constituents or marker components in various parts of the plants. Earlier studies have estimated phytoconstituents from the stem and other aerial plant parts of Cissus quadrangularis Linn. Estimation of hydrocarbons can also be successfully done using HPTLC technique using suitable derivatization. Aims: To develop and validate a simple and rapid method for the estimation of long chain aliphatic hydrocarbons from the leaves of C. quadrangularis using HPTLC technique. Methods: Precoated silica gel 60 F254 plates were used as stationary phase. The mobile phase used was hexane (100 %. The detection of spots was carried out using berberine sulphate as detecting reagent. Results: The method was validated in terms of linearity, sensitivity, accuracy, and precision. Linearity range was found to be 2-10 µg/mL, limit of detection 0.127 µg/mL, and limit of quantification 0.384 µg/mL. Conclusions: A novel, simple, accurate, precise and sensitive HPTLC method has been developed and validated for the estimation of long chain aliphatic hydrocarbons obtained from the leaves of C. quadrangularis Linn.

  7. Tuneable surface enhanced Raman spectroscopy hyphenated to chemically derivatized thin-layer chromatography plates for screening histamine in fish.

    Science.gov (United States)

    Xie, Zhengjun; Wang, Yang; Chen, Yisheng; Xu, Xueming; Jin, Zhengyu; Ding, Yunlian; Yang, Na; Wu, Fengfeng

    2017-09-01

    Reliable screening of histamine in fish was of urgent importance for food safety. This work presented a highly selective surface enhanced Raman spectroscopy (SERS) method mediated by thin-layer chromatography (TLC), which was tailored for identification and quantitation of histamine. Following separation and derivatization with fluram, plates were assayed with SERS, jointly using silver nanoparticle and NaCl. The latter dramatically suppressed the masking effect caused by excessive fluram throughout the plate, thus offering clear baseline and intensive Raman fingerprints specific to the analyte. Under optimized conditions, the usability of this method was validated by identifying the structural fingerprints of both targeted and unknown compounds in fish samples. Meanwhile, the quantitative results of this method agreed with those by an HPLC method officially suggested by EU for histamine determination. Showing remarkable cost-efficiency and user-friendliness, this facile TLC-SERS method was indeed screening-oriented and may be more attractive to controlling laboratories of limited resource. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Analysis of low active-pharmaceutical-ingredient signal drugs based on thin layer chromatography and surface-enhanced Raman spectroscopy.

    Science.gov (United States)

    Li, Xiao; Chen, Hui; Zhu, Qingxia; Liu, Yan; Lu, Feng

    2016-11-30

    Active pharmaceutical ingredients (API) embedded in the excipients of the formula can usually be unravelled by normal Raman spectroscopy (NRS). However, more and more drugs with low API content and/or low Raman scattering coefficient were insensitive to NRS analysis, which was for the first time defined as Low API-Signal Drugs (LASIDs) in this paper. The NRS spectra of these LASIDs were similar to their dominant excipients' profiles, such as lactose, starch, microcrystalline cellulose (MCC), etc., and were classified into three types as such. 21 out of 100 kinds of drugs were screened as LASIDs and characterized further by Raman microscopic mapping. Accordingly, we proposed a tailored solution to the qualitation and quantitation problem of these LASIDs, using surface-enhanced Raman spectroscopic (SERS) detection on the thin layer chromatographic (TLC) plate both in situ and after-separation. Experimental conditions and parameters including TLC support matrix, SERS substrate, detection mode, similarity threshold, internal standard, etc., were optimized. All LASIDs were satisfactorily identified and the quantitation results agreed well with those of high performance liquid chromatography (HPLC). For some structural analogues of LASIDs, although they presented highly similar SERS spectra and were tough to distinguish even with Raman microscopic mapping, they could be successfully discriminated from each other by coupling SERS (with portable Raman spectrometer) with TLC. These results demonstrated that the proposed solution could be employed to detect the LASIDs with high accuracy and cost-effectiveness. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Re-evaluation of thin layer chromatography as an alternative method for the quantification of prostaglandins from rat Kupffer cells.

    Science.gov (United States)

    Pestel, Sabine; Jungermann, Kurt; Schieferdecker, Henrike L

    2005-01-01

    In contrast to conventionally used immunoassays, thin layer chromatography (TLC)--by prelabeling of cells with radioactive arachidonic acid (AA)--allows to differentiate between cellularly built and added prostanoids and thus to investigate feedback effects of prostanoids on their own release. PGD2, TXB2 and PGE2 released from zymosan-stimulated Kupffer cells were separated with distinct RF-values, corresponding to those of the pure substances. Quantification of PGD2 and PGE2 gave comparable results with TLC and immunoassays, but measurement in the presence of added prostanoids was only possible with TLC. Moreover TLC was superior to immunoassays in having a longer linear range while being comparably sensitive. Cellularly built TXB2 in its radioactively labeled form was not detectable by TLC. Inhibition of TXB2 release by externally added AA or technical artifacts were excluded, suggesting that the cellular AA-pools used for prostaglandin and thromboxane synthesis differ in their accessibility for added AA. Thus, TLC is a simple, sensitive and precise method for the quantification of cellularly built prostaglandins but not of thromboxane even in the presence of added prostanoids.

  10. Comparison of results for morphine urinalyses by radioimmunoassay and thin-layer chromatography in a narcotic clinic setting.

    Science.gov (United States)

    Kokoski, R J; Jain, M

    1975-03-01

    Radioimmunoassay (RIA) and thin-layer chromatography (TLC) were compared for morphine detection in an actual narcotic clinic setting. A choice of urines from all those screened by TLC allowed a critical comparison as to actual use or non-use of narcotic drugs, rather than a sampling at random in which the question of possible false positives or negatives cannot be conclusively answered. Although RIA is more sensitive than TLC, its advantage is apparent only in those cases where urine specimens are difficult to obtain frequently regularly or where the use of morphine is suspected by the positive identification of quinine in urine that was morphine-negative by TLC. In a selected group of negative and positive specimens chosen without conscious bias, the two methods gave consistently similar results, indicating that the modified TLC method provided a few or no false positives or negatives if the negatives were from those cases that were not positive anytime up to 3-4 days before urine collection. We conclude that RIA can be of significant value as a supplement to a TLC screening program, without sacrificing the many advantages that TLC has to offer.

  11. Immunoaffinity column clean-up and thin layer chromatography for determination of ochratoxin A in green coffee.

    Science.gov (United States)

    Santos, E A; Vargas, E A

    2002-05-01

    An immunoaffinity clean-up-based method for determining ochratoxin A (OTA) in green coffee aiming at one-dimensional thin layer chromatography (TLC) analysis was established. OTA was extracted with a mixture of methanol and aqueous sodium hydrogen carbonate solution, purified through an immunoaffinity column, separated on normal or reversed-phase (RP) TLC plates and detected and quantified by visual and densitometric analysis. The linear equation of the standard calibration curve by densitometric analysis gave R(2) > 0.999 (0.04-84 ng). The mean recovery (R) of OTA from spiked samples (1.8-109 microg kg(-1)) by densitometric and visual analyses were 98.4 and 103.8%, respectively. The relative standard deviations (RSD) for densitometric and visual analysis varied from 1.1 to 24.9% and from 0.0 to 18.8%, respectively. The RSD for naturally contaminated samples by densitometry (three levels of contamination, n = 3) varied from 11.1 to 18.1%. The correlation (R(2)) between high-performance liquid chromatography (HPLC) and densitometry, and between visual and densitometric analysis for spiked samples were > 0.99. The limit of detection (LOD) of the method was 0.5 microg kg(-1) for normal TLC. Toluene-ethyl acetate-88% formic acid (6:3:1 v/v/v) and acetonitrile-methanol-water-glacial acetic acid (35:35:29:10 v/v/v/v) were regarded as the suitable TLC solvents for eluting both standards and samples on normal and RP TLC plates, respectively. Toluene-acetic acid (99:1 v/v) was chosen as the spotting solvent among several others for giving the best sensitivity and resolution of OTA on TLC plates as well as the best recovery of OTA from standard and sample extract residues. Preliminary studies were carried out to investigate the reuse of the immunoaffinity column and the interference of caffeine in the OTA recovery.

  12. Qualitative and quantitative two-dimensional thin-layer chromatography/high performance liquid chromatography/diode-array/electrospray-ionization-time-of-flight mass spectrometry of cholinesterase inhibitors.

    Science.gov (United States)

    Mroczek, Tomasz

    2016-09-10

    Recently launched thin-layer chromatography-mass spectrometry (TLC-MS) interface enabling extraction of compounds directly from TLC plates into MS ion source was unusually extended into two-dimensional thin-layer chromatography/high performance liquid chromatography (2D, TLC/HPLC) system by its a direct connection to a rapid resolution 50×2.1mm, I.D. C18 column compartment followed by detection by diode array (DAD) and electrospray ionisation time-of-flight mass spectrometry (ESI-TOF-MS). In this way, even not separated bands of complicated mixtures of natural compounds could be analysed structurally, only within 1-2min after development of TLC plates. In comparison to typically applied TLC-MS interface, no ion suppression for acidic mobile phases was observed. Also, substantial increase in ESI-TOF-MS sensitivities and quality of spectra, were noticed. It has been utilised in combination with TLC- based bioautographic approaches of acetylcholinesterase (AChE) inhibitors, However, it can be also applied in any other procedures related to bioactivity (e.g. 2,2-Diphenyl-1-picryl-hydrazyl-DPPH screen test for radicals). This system has been also used for determination of half maximal inhibitory concentration (IC50 values) of the active inhibitor-galanthamine, as an example. Moreover, AChE inhibitory potencies of some of purified plant extracts, never studied before, have been quantitatively measured. This is first report of usage such the 2D TLC/HPLC/MS system both for qualitative and quantitative evaluation of cholinesterase inhibitors in biological matrices. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Application of thin-layer chromatography of fat and oil, fatty acid and mineral oil for science education. Yushi, shibosan, koyu no hakuso chromatography to sono kyozaiteki katsuyo

    Energy Technology Data Exchange (ETDEWEB)

    Kawabuchi, K [Ehime Univ., Ehime (Japan); Takechi, Y; Morimoto, M [Ehime (Japan)

    1990-08-20

    In this article, with regard to application of thin-layer chromatography of fat and oil, fatty acid and mineral oil for science education, a study was made mainly on quality finding of n-hexane extracts provided in the law of prevention of water pollution, and separation of hydrolysis products of fat and oil. As a result, the existance of fat and oil, fatty acid and mineral oil in the enviromental water and the hydrolysis process of fat and oil could experimentally be confirmed. This is considered to be useful for studying teaching material on fat and oil. This report deals with the reagents and device, and specifies standard solution, thin-layer plate, spread solvent, spread tank and thermostat, and states, for its operation, the method using enzyme for hydrolysis of fat and oil and the method using potassium hydroxide. It also contemplates on R {sub f} values of fat and oil, fatty acid and mineral oil, etc., as well as spread of fat and oil, oils contained in n-hexane extracts and hydrolysis products of fat and oil. 6 refs., 4 figs., 1 tab.

  14. Reversed-phase thin-layer chromatography of homologs of Antimycin-A and related derivatives

    Science.gov (United States)

    Abidi, Sharon L.

    1989-01-01

    Using a reversed-phase high-performance liquid chromatographic (HPLC) technique, a mixture of antimycins A was separated into eight hitherto unreported subcomponents, Ala, Alb, A2a, A2b, A3a, A3b, A4a, and A4b. Although a base-line resolution of the known four major antimycins Al, A2, A3, and A4 was readily achieved with mobile phases containing acetate buffers, the separation of the new antibiotic subcomponents was highly sensitive to variation in mobile phase conditions. The type and composition of organic modifiers, the nature of buffer salts, and the concentration of added electrolytes had profound effects on capacity factors, separation factors, and peak resolution values. Of the numerous chromatographic systems examined, a mobile phase consisting of methanol-water (70:30) and 0.005 M tetrabutylammonium phosphate at pH 3.0 yielded the most satisfactory results for the separation of the subcomponents. Reversed-phase gradient HPLC separation of the dansylated or methylated antibiotic compounds produced superior chromatographic characteristics and the presence of added electrolytes was not a critical factor for achieving separation. Differences in the chromatographic outcome between homologous and structural isomers were interpretated based on a differential solvophobic interaction rationale. Preparative reversed-phase HPLC under optimal conditions enabled isolation of pure samples of the methylated antimycin subcomponents for use in structural studies.

  15. Feasibility of correlating separation of ternary mixtures of neutral analytes via thin layer chromatography with supercritical fluid chromatography in support of green flash separations.

    Science.gov (United States)

    Ashraf-Khorassani, M; Yan, Q; Akin, A; Riley, F; Aurigemma, C; Taylor, L T

    2015-10-30

    Method development for normal phase flash liquid chromatography traditionally employs preliminary screening using thin layer chromatography (TLC) with conventional solvents on bare silica. Extension to green flash chromatography via correlation of TLC migration results, with conventional polar/nonpolar liquid mixtures, and packed column supercritical fluid chromatography (SFC) retention times, via gradient elution on bare silica with a suite of carbon dioxide mobile phase modifiers, is reported. Feasibility of TLC/SFC correlation is individually described for eight ternary mixtures for a total of 24 neutral analytes. The experimental criteria for TLC/SFC correlation was assumed to be as follows: SFC/UV/MS retention (tR) increases among each of the three resolved mixture components; while, TLC migration (Rf) decreases among the same resolved mixture components. Successful correlation of TLC to SFC was observed for most of the polar organic solvents tested, with the best results observed via SFC on bare silica with methanol as the CO2 modifier and TLC on bare silica with a methanol/dichloromethane mixture. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Instant thin layer chromatography (ITLC) - the most true and convenient method for the determination of radiochemical purity of Tc-99m Labeled radiopharmaceuticals

    International Nuclear Information System (INIS)

    Anwar-Ul-Azim, M.; Ansari, M.I.H.

    2007-01-01

    Full text: Determination of radiochemical purity usually involves paper chromatography method or some column chromatography such as ion exchange or gel filtration technique. In this study, a modified chromatography method with thin-layer support called instant thin Layer chromatography (ITLC) was used for the measurement of radiochemical purity. The aim of the study was to present instant thin layer chromatography-Silica-Gel (ITLC-SG) technique as a fairly rapid , convenient and inexpensive system for the screening of radiochemical impurities of 99mTc-labeled radiopharmaceuticals resulting from physical , chemical and/or radiation decomposition. Materials and Methods: The experiment was carried out at the Institute of Nuclear Medicine and Ultrasound, Dhaka for a period of 10 months from August '05 to May '06. Radiochemical purity of seven types of 99mTc-labeled radiopharmaceuticals, namely 99mTc-DTPA,99mTc- MI I, 99m Tc - HDP, 99m Tc - DMSA, 99m Tc - Tetofosmin, 99mTc-Fyton and 99mTc-ECD were measured by the use of two solvent dual-instant thin layer chromatography systems. Commercially available instant thin layer chromatography plate ( 20cm x20cm) impregnated with silica gel (ITLC-SG: Merck, Germany) was used as a stationary phase for the measurement of radiochemical impurities.Acetone, Ethyl methyl ketone, chloroform and methanol were used to measure the amount of free pertechnetate in the labelled radiopharmaceuticals and 0.9% saline was used in all cases as solvent (Mobile phase) to measure the amount of the hydrolyzed-reduced technetium colloid. Results: The results showed that the measured radiochemical purity of 99mTc-DTPA, 99mTc-MIBI, 99mTc-HDP, 99mTc-DMSA, 99mTc-Tetofosmin, 99mTc-Fyton and 99mTc-ECD were acceptable for all the studied samples except two samples of 99mTc-MIBI, one sample of 99mTc-Fyton and two samples of 99mTc-ECD, where the measured radiochemical purity were not within the acceptable RCP limits of commonly used radiopharmaceuticals (RCP

  17. Quantitative determination of 3,4-methylenedioxymethamphetamine by thin-layer chromatography in ecstasy illicit pills in Tehran.

    Science.gov (United States)

    Shetab Boushehri, Seyed Vahid; Tamimi, Maryam; Kebriaeezadeh, Abbas

    2009-11-01

    3,4-Methylenedioxymethamphetamine (MDMA) is the major ingredient of ecstasy illicit pills. It is a hallucinogen, central nervous system stimulant, and serotonergic neurotoxin that strongly releases serotonin from serotonergic nerves terminals. Moreover, it releases norepinephrine and dopamine from nerves terminal, but to a lesser extent than serotonin. Poisoning and even death from abusing MDMA-containing ecstasy illicit pills among abusers is usual. Thus, quantitative determination of MDMA content of ecstasy illicit pills in illicit drug bazaar must be done regularly to find the most high dose ecstasy illicit pills and removing them from illicit drug bazaar. In the present study, MDMA contents of 13 most abundant ecstasy illicit pills were determined by quantitative thin-layer chromatography (TLC). Two procedures for quantitative determination of MDMA contents of ecstasy illicit pills by TLC were used: densitometric and so-called 'scraping off' methods. The former was done in a reflection mode at 285 nm and the latter was done by absorbance measurement of eluted scraped off spots. Limit of detection (LOD), considering signal-to-noise ratio (S/N) of 2, and limit of quantification (LOQ), regarding S/N of 10, of densitometric and scraping off methods were 0.40 microg, 1.20 microg, and 6.87 mug, 20.63 microg, respectively. Repeatabilities (within-laboratory error) of densitometric and scraping off methods were 0.5% and 3.6%, respectively. The results showed that the ecstasy illicit pills contained 24-124.5 mg and 23.9-122.2 mg MDMA by densitometric and scraping off methods, respectively.

  18. Thin layer chromatography fingerprint, antioxidant, and antibacterial activities of rhizomes, stems, and leaves of Curcuma aeruginosa Roxb.

    Science.gov (United States)

    Safitri, A.; Batubara, I.; Khumaida, N.

    2017-05-01

    Fingerprints of 5 temu hitam (Curcuma aeruginosa Roxb.) accessions (Malang, Cirebon, Kuningan 1, Bogor, and Liwa) were determined by thin-layer chromatography (TLC) and compared to fingerprints of turmeric (Curcuma longa L), temu putih (Curcuma zedoaria (Christm.) Roscoe), and temu lawak (Curcuma zanthorriza Roxb.). Maceration method with ethanol as the solvent was used for extraction. The eluent used for fingerprint by TLC was chloroform:dichloromethane (9:1v/v). Five accessions of temu hitam show similar fingerprint patterns, but different in band thickness. Temu hitam rhizomes have bands of curcuminoid (Rf 0.22, 0.10, 0.03), and characteristic bands of Rf 0.42, 0.27, and 0.77, which can be distinguished from turmeric and temu lawak and Rf 0.13, which is different from temu putih. Leaves and stems of temu hitam can be distinguished from temu putih, turmeric, and temu lawak at Rf 0.60. Rhizomes of all plants reveal strong antibacterial activity against Staphylococcus aureus and antioxidant activity on DPPH radicals than its corresponding stems and leaves. Antibacterial and antioxidant activities were determined by microdilution and TLC-bioautography. Antibacterial activity of rhizomes of Cirebon and Kuningan 1 accessions are higher than that of other accessions (MIC = 250 μg/mL MBC = 500 μg/mL, but lower as compared to that of temu lawak (MIC = 62.5 μg/mL, MBC = 250 μg/mL) and tetracycline (MIC = MBC = 15.63 μg/mL). Rhizome of Liwa accession exhibits the highest antioxidant activity (IC50 = 124.88 μg/mL) amongst all accessions, but lower than that of temu lawak (IC50 = 18.45 μg/mL), turmeric (IC50 = 18.82 μg/mL), and temu putih (IC50 = 94.35 μg/mL).

  19. Chromatographical analysis of phenolic acids in some species of Polygonum L. genus. Part 1 Qualitative analysis by two-dimensional thin layer chromatography (TLC

    Directory of Open Access Journals (Sweden)

    Helena D. Smolarz

    2014-01-01

    Full Text Available The Two-Dimensional Thin Layer Chromatography method has been used for the separation and identification of phenolic acids from six taxons of Pohygonum L. genus. The following acids were found: caffeic, p-coumaric, ferulic, p-hydroxybenzoic, m-hydroxybenzoic, vanillic, syringic, p-hydroxyphenylacetic, o-hydroxyphenylacetic, synapic, melillotic, salicylic, gentisic, elagic, gallic, chlorogenic, protocatechuic and homoprotocatechuic. Gallic, ferulic, vanillic, p-coumaric and p-hydroxybenzoic acids were isolated from herb Polygonum convolvulus L. using column chromatography.

  20. Thin-layer chromatography coupled with high performance liquid chromatography for determining tetrabromobisphenol A/S and their derivatives in soils.

    Science.gov (United States)

    Liu, Aifeng; Shen, Zhaoshuang; Tian, Yong; Shi, Rongguang; Liu, Yi; Zhao, Zongshan; Xian, Mo

    2017-12-01

    As brominated flame retardants (BFRs), tetrabromobisphenol A/S (TBBPA/S) and their derivatives have raised wide concerns owing to their widely usage, distributions and adverse effects on human health, thus monitoring these BFRs was urgently needed. In this study, a rapid and cost-effective method based on thin-layer chromatography (TLC) sample pre-treatment coupled with high performance liquid chromatography-diode array detector (HPLC-DAD) (UV=214nm) was developed for determining TBBPA/S and their derivatives in soils, including TBBPA, TBBPA bis(allyl ether) (TBBPA-BAE), TBBPA bis(2,3-dibromopropyl ether) (TBBPA-BDBPE), TBBPS bis(allyl ether) (TBBPS-BAE) and TBBPS bis(2,3-dibromopropyl ether) (TBBPS-BDBPE). The method detection limits (MDLs) and the method quantification limits (MQLs) for these BFRs ranged from 0.023 to 0.087μgg -1 dw and 0.076-0.29μgg -1 dw, respectively. The recoveries were 41-108% and both RSD of repeatability and intermediate precision were less than 11%. The developed method presented good performance for analyzing natural soil samples collected from BFRs industrial park, suggesting its great application potential for monitoring environmental TBBPA/S and their derivatives. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. [In situ thin layer chromatography-fourier transform-surface-enhanced Raman spectrum study on ingredients of berberine].

    Science.gov (United States)

    Wang, Yuan; Guo, Zhan-sheng; Wang, Ying-feng; Wang, Song-ying; Ren, Gui-fen; Zhang, Xiang-lan; Han, Xiu-lan

    2002-10-01

    Surface Enhanced Raman Scattering (SERS) combined with Thin Layer Chromatography (TLC) has been used for studying characteristic spectrum of molecules in situ in micrograms samples. There are very few report for applying the SERS-TCL method in the study of the effective ingredients of Chinese traditional herbs. Coptis Chinensis France is an often-used clinic Chinese traditional medicine. Its main effective components include berberine and so on, which have antibiotic very wide and also have curative effect on improving the functions of heart vascular cycles. Therefore the concentrations of berberine are very important for the quality control of the medicine. In this work, the ethanol extract of Coptis Chinensis France was first separated by TLC, the SERS was then measure directly after dropping silver gel on the separated spots. The method can be used for the finger print analysis of the berberine. 3 microL of alcohol extract of Coptis Chinensis France with total alkaloids concentration of 1.0 mg.mL was placed on silicon GF254 TLC plate. The sample was separated by developing solvent of n bulanol-Acitic acid-H2O (7:2:1 V/V). The positions of berberine in the sample were confirmed by the standard alkaloid solutions. The Rf values for berberine are 0.29. The silver gel was used as surface enhanced substrate and placed on the separated berberine spots. FT-SERS was measured directly by a Nicolet FT-Raman 910 spectrometer. Berberine belong to isoquinoline alkaloids. His structure can be found in reference. The date of spectrum of berberine can be seen that the band at 1,396 cm-1 due to Ar-OCH3 deformation vibrations was greatly enhanced, indicating that the molecule was absorbed on silver gel strongly through lone-pair electron in Ar-OCH3. The ring stretching mode occurring around 1,548 cm-1 represents isoquinoline ring in the molecule. The band at 727 cm-1 due to CH (ring) deformation vibrations was also enhanced.

  2. The detection of some halogenated phenols and nitrophenols in thin-layer chromatography by means of bromine

    NARCIS (Netherlands)

    Tadema, G.; Batelaan, P.H.

    1968-01-01

    A method is described for the detection of halogeno- and nitro-phenols in sub-microgram quantities. Theses compounds are made visible by exposure of the developed thin layer plates to bromine vapour and subsequent spraying with an aqueous solution of potassium iodide or an ethanolic solution of

  3. Evaluation of a thin-layer chromatographic technique for ...

    African Journals Online (AJOL)

    Methanol extracts of both fistula and bush samples were prepared and analysed by thin-layer chromatography. Chromatoplates, when visualised under ultraviolet light, revealed a number of fluorescent compounds, some of which were common in both the fistula and bush sample extracts. By comparing the presence of ...

  4. Quantitative Thin-Layer Chromatography/Mass Spectrometry Analysis of Caffeine Using a Surface Sampling Probe Electrospray Ionization Tandem Mass Spectrometry System

    Energy Technology Data Exchange (ETDEWEB)

    Ford, Michael J [ORNL; Deibel, Michael A. [Earlham College; Tomkins, Bruce A [ORNL; Van Berkel, Gary J [ORNL

    2005-01-01

    Quantitative determination of caffeine on reversed-phase C8 thin-layer chromatography plates using a surface sampling electrospray ionization system with tandem mass spectrometry detection is reported. The thin-layer chromatography/electrospray tandem mass spectrometry method employed a deuterium-labeled caffeine internal standard and selected reaction monitoring detection. Up to nine parallel caffeine bands on a single plate were sampled in a single surface scanning experiment requiring 35 min at a surface scan rate of 44 {mu}m/s. A reversed-phase HPLC/UV caffeine assay was developed in parallel to assess the mass spectrometry method performance. Limits of detection for the HPLC/UV and thin-layer chromatography/electrospray tandem mass spectrometry methods determined from the calibration curve statistics were 0.20 ng injected (0.50 {mu}L) and 1.0 ng spotted on the plate, respectively. Spike recoveries with standards and real samples ranged between 97 and 106% for both methods. The caffeine content of three diet soft drinks (Diet Coke, Diet Cherry Coke, Diet Pepsi) and three diet sport drinks (Diet Turbo Tea, Speed Stack Grape, Speed Stack Fruit Punch) was measured. The HPLC/UV and mass spectrometry determinations were in general agreement, and these values were consistent with the quoted values for two of the three diet colas. In the case of Diet Cherry Coke and the diet sports drinks, the determined caffeine amounts using both methods were consistently higher (by 8% or more) than the literature values.

  5. Determination of Four Major Saponins in Skin and Endosperm of Seeds of Horse Chestnut (Aesculus Hippocastanum L.) Using High Performance Liquid Chromatography with Positive Confirmation by Thin Layer Chromatography

    OpenAIRE

    Abudayeh, Zead Helmi Mahmoud; Al Azzam, Khaldun Mohammad; Naddaf, Ahmad; Karpiuk, Uliana Vladimirovna; Kislichenko, Viktoria Sergeevna

    2015-01-01

    urpose: To separate and quantify four major saponins in the extracts of the skin and the endosperm of seeds of horse chestnut (Aesculus hippocastanum L.) using ultrasonic solvent extraction followed by a high performance liquid chromatography-diode array detector (HPLC-DAD) with positive confirmation by thin layer chromatography (TLC). Methods: The saponins: escin Ia, escin Ib, isoescin Ia and isoescin Ib were extracted using ultrasonic extraction method. The optimized ex...

  6. Simplified and rapid method for extraction of ergosterol from natural samples and detection with quantitative and semi-quantitative methods using thin-layer chromatography

    OpenAIRE

    Larsen, Cand.scient Thomas; Ravn, Senior scientist Helle; Axelsen, Senior Scientist Jørgen

    2004-01-01

    A new and simplified method for extraction of ergosterol (ergoste-5,7,22-trien-3-beta-ol) from fungi in soil and litter was developed using pre-soaking extraction and paraffin oil for recovery. Recoveries of ergosterol were in the range of 94 - 100% depending on the solvent to oil ratio. Extraction efficiencies equal to heat-assisted extraction treatments were obtained with pre-soaked extraction. Ergosterol was detected with thin-layer chromatography (TLC) using fluorodensitometry with a quan...

  7. Óleo essencial de limão no ensino da cromatografia em camada delgada Lime essential oil in the teaching of thin layer chromatography

    Directory of Open Access Journals (Sweden)

    Rosaly S. Silva

    2009-01-01

    Full Text Available This paper describes a simple experiment employing the essential oil of limes which can be applied in undergraduate organic chemistry laboratory classes for the teaching of thin layer chromatography (TLC. The experiment consists in submit lime peel oil to TLC separation employing hexane and dichloromethane as the eluents and five different systems for visualization of the chromatogram. In one experiment it is possible to teach the different variables of the TLC technique. This experiment may also be performed following vapor distillation and liquid-liquid extraction technique in experimental classes.

  8. Thin layer chromatography coupled with surface-enhanced Raman scattering as a facile method for on-site quantitative monitoring of chemical reactions.

    Science.gov (United States)

    Zhang, Zong-Mian; Liu, Jing-Fu; Liu, Rui; Sun, Jie-Fang; Wei, Guo-Hua

    2014-08-05

    By coupling surface-enhanced Raman spectroscopy (SERS) with thin layer chromatography (TLC), a facile and powerful method was developed for on-site monitoring the process of chemical reactions. Samples were preseparated on a TLC plate following a common TLC procedure, and then determined by SERS after fabricating a large-area, uniform SERS substrate on the TLC plate by spraying gold nanoparticles (AuNPs). Reproducible and strong SERS signals were obtained with substrates prepared by spraying 42-nm AuNPs at a density of 5.54 × 10(10) N/cm(2) on the TLC plate. The capacity of this TLC-SERS method was evaluated by monitoring a typical Suzuki coupling reaction of phenylboronic acid and 2-bromopyridine as a model. Results showed that this proposed method is able to identify reaction product that is invisible to the naked eye, and distinguish the reactant 2-bromopyridine and product 2-phenylpyridine, which showed almost the same retention factors (R(f)). Under the optimized conditions, the peak area of the characteristic Raman band (755 cm(-1)) of the product 2-phenylpyridine showed a good linear correlation with concentration in the range of 2-200 mg/L (R(2) = 0.9741), the estimated detection limit (1 mg/L 2-phenylpyridine) is much lower than the concentration of the chemicals in the common organic synthesis reaction system, and the product yield determined by the proposed TLC-SERS method agreed very well with that by UPLC-MS/MS. In addition, a new byproduct in the reaction system was found and identified through continuous Raman detection from the point of sample to the solvent front. This facile TLC-SERS method is quick, easy to handle, low-cost, sensitive, and can be exploited in on-site monitoring the processes of chemical reactions, as well as environmental and biological processes.

  9. Determination of Sudan I in paprika powder by molecularly imprinted polymers-thin layer chromatography-surface enhanced Raman spectroscopic biosensor.

    Science.gov (United States)

    Gao, Fang; Hu, Yaxi; Chen, Da; Li-Chan, Eunice C Y; Grant, Edward; Lu, Xiaonan

    2015-10-01

    Sudan I is a carcinogenic and mutagenic azo-compound that has been utilized as a common adulterant in spice and spice blends to impart a desirable red color to foods. A novel biosensor combining molecularly imprinted polymers (MIPs), thin layer chromatography (TLC) and surface enhanced Raman spectroscopy (SERS) could determine Sudan I levels in paprika powder to 1 ppm (or 2 ng/spot). Sudan I spiked paprika extracts (spiking levels: 0, 1, 5, 10, 40, 70 and 100 ppm) were prepared. Sudan I imprinted polymers were synthesized by employing the interaction between Sudan I (template) and methacrylic acid (functional monomer), followed by washing to remove Sudan I leaving the Sudan I-binding sites exposed. MIPs were used as a stationary phase for TLC and could selectively retain Sudan I at the original spot with little interference. A gold colloid SERS substrate could enhance Raman intensity for Sudan I in this MIP-TLC system. Principal component analysis plot and partial least squares regression (R(2)=0.978) models were constructed and a linear regression model (R(2)=0.983) correlated spiking levels (5, 10, 40, 70 and 100 ppm) with the peak intensities (721 cm(-1)) of Sudan I SERS spectra. Both separation (30-40s) and detection (1s or 0.1s) were extremely fast by using both commercial bench-top and custom made portable Raman spectrometers. This biosensor can be applied as a rapid, low-cost and reliable tool for screening Sudan I adulteration in foods. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Facile on-site detection of substituted aromatic pollutants in water using thin layer chromatography combined with surface-enhanced Raman spectroscopy.

    Science.gov (United States)

    Li, Dawei; Qu, Lulu; Zhai, Wenlei; Xue, Jinqun; Fossey, John S; Long, Yitao

    2011-05-01

    A novel facile method for on-site detection of substituted aromatic pollutants in water using thin layer chromatography (TLC) combined with surface-enhanced Raman spectroscopy (SERS) was explored. Various substituted aromatics in polluted water were separated by a convenient TLC protocol and then detected using a portable Raman spectrometer with the prepared silver colloids serving as SERS-active substrates. The effects of operating conditions on detection efficacy were evaluated, and the application of TLC-SERS to on-site detection of artificial and real-life samples of aromatics/polluted water was systematically investigated. It was shown that commercially available Si 60-F(254) TLC plates were suitable for separation and displayed low SERS background and good separation efficiency, 2 mM silver colloids, 20 mM NaCl (working as aggregating agent), 40 mW laser power, and 50 s intergration time were appropriate for the detection regime. Furthermore, qualitative and quantitative detection of most of substituted aromatic pollutants was found to be readily accomplished using the developed TLC-SERS technique, which compared well with GC-MS in terms of identification ability and detection accuracy, and a limit of detection (LOD) less than 0.2 ppm (even at ppb level for some analytes) could be achieved under optimal conditions. The results reveal that the presented convenient method could be used for the effective separation and detection of the substituted aromatic pollutants of water on site, thus reducing possible influences of sample transportation and contamination while shortening the overall analysis time for emergency and routine monitoring of the substituted aromatics/polluted water.

  11. Thin Layer Chromatography-Bioautography and Gas Chromatography-Mass Spectrometry of Antimicrobial Leaf Extracts from Philippine Piper betle L. against Multidrug-Resistant Bacteria

    Directory of Open Access Journals (Sweden)

    Demetrio L. Valle

    2016-01-01

    Full Text Available This study isolated and identified the antimicrobial compounds of Philippine Piper betle L. leaf ethanol extracts by thin layer chromatography- (TLC- bioautography and gas chromatography-mass spectrometry (GC-MS. Initially, TLC separation of the leaf ethanol extracts provided a maximum of eight compounds with Rf values of 0.92, 0.86, 0.76, 0.53, 0.40, 0.25, 0.13, and 0.013, best visualized when inspected under UV 366 nm. Agar-overlay bioautography of the isolated compounds demonstrated two spots with Rf values of 0.86 and 0.13 showing inhibitory activities against two Gram-positive multidrug-resistant (MDR bacteria, namely, methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus. The compound with an Rf value of 0.86 also possessed inhibitory activity against Gram-negative MDR bacteria, namely, carbapenem-resistant Enterobacteriaceae-Klebsiella pneumoniae and metallo-β-lactamase-producing Acinetobacter baumannii. GC-MS was performed to identify the semivolatile and volatile compounds present in the leaf ethanol extracts. Six compounds were identified, four of which are new compounds that have not been mentioned in the medical literature. The chemical compounds isolated include ethyl diazoacetate, tris(trifluoromethylphosphine, heptafluorobutyrate, 3-fluoro-2-propynenitrite, 4-(2-propenylphenol, and eugenol. The results of this study could lead to the development of novel therapeutic agents capable of dealing with specific diseases that either have weakened reaction or are currently not responsive to existing drugs.

  12. Thin Layer Chromatography-Bioautography and Gas Chromatography-Mass Spectrometry of Antimicrobial Leaf Extracts from Philippine Piper betle L. against Multidrug-Resistant Bacteria.

    Science.gov (United States)

    Valle, Demetrio L; Puzon, Juliana Janet M; Cabrera, Esperanza C; Rivera, Windell L

    2016-01-01

    This study isolated and identified the antimicrobial compounds of Philippine Piper betle L. leaf ethanol extracts by thin layer chromatography- (TLC-) bioautography and gas chromatography-mass spectrometry (GC-MS). Initially, TLC separation of the leaf ethanol extracts provided a maximum of eight compounds with R f values of 0.92, 0.86, 0.76, 0.53, 0.40, 0.25, 0.13, and 0.013, best visualized when inspected under UV 366 nm. Agar-overlay bioautography of the isolated compounds demonstrated two spots with R f values of 0.86 and 0.13 showing inhibitory activities against two Gram-positive multidrug-resistant (MDR) bacteria, namely, methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus. The compound with an R f value of 0.86 also possessed inhibitory activity against Gram-negative MDR bacteria, namely, carbapenem-resistant Enterobacteriaceae-Klebsiella pneumoniae and metallo-β-lactamase-producing Acinetobacter baumannii. GC-MS was performed to identify the semivolatile and volatile compounds present in the leaf ethanol extracts. Six compounds were identified, four of which are new compounds that have not been mentioned in the medical literature. The chemical compounds isolated include ethyl diazoacetate, tris(trifluoromethyl)phosphine, heptafluorobutyrate, 3-fluoro-2-propynenitrite, 4-(2-propenyl)phenol, and eugenol. The results of this study could lead to the development of novel therapeutic agents capable of dealing with specific diseases that either have weakened reaction or are currently not responsive to existing drugs.

  13. Development and validation of high-performance liquid chromatography and high-performance thin-layer chromatography methods for the quantification of khellin in Ammi visnaga seed

    Science.gov (United States)

    Kamal, Abid; Khan, Washim; Ahmad, Sayeed; Ahmad, F. J.; Saleem, Kishwar

    2015-01-01

    Objective: The present study was used to design simple, accurate and sensitive reversed phase-high-performance liquid chromatography RP-HPLC and high-performance thin-layer chromatography (HPTLC) methods for the development of quantification of khellin present in the seeds of Ammi visnaga. Materials and Methods: RP-HPLC analysis was performed on a C18 column with methanol: Water (75: 25, v/v) as a mobile phase. The HPTLC method involved densitometric evaluation of khellin after resolving it on silica gel plate using ethyl acetate: Toluene: Formic acid (5.5:4.0:0.5, v/v/v) as a mobile phase. Results: The developed HPLC and HPTLC methods were validated for precision (interday, intraday and intersystem), robustness and accuracy, limit of detection and limit of quantification. The relationship between the concentration of standard solutions and the peak response was linear in both HPLC and HPTLC methods with the concentration range of 10–80 μg/mL in HPLC and 25–1,000 ng/spot in HPTLC for khellin. The % relative standard deviation values for method precision was found to be 0.63–1.97%, 0.62–2.05% in HPLC and HPTLC for khellin respectively. Accuracy of the method was checked by recovery studies conducted at three different concentration levels and the average percentage recovery was found to be 100.53% in HPLC and 100.08% in HPTLC for khellin. Conclusions: The developed HPLC and HPTLC methods for the quantification of khellin were found simple, precise, specific, sensitive and accurate which can be used for routine analysis and quality control of A. visnaga and several formulations containing it as an ingredient. PMID:26681890

  14. [A thin-layer chromatography method for determining the styrene metabolites mandelic and phenylglyoxylic acid in urine].

    Science.gov (United States)

    Gartzke, J; Burck, D

    1989-06-01

    A thin-layer chromatographic method is described for the determination of mandelic and phenyglyoxillic acid on silicagel (Silufol UV 254) after extraction from urine of styrene exposed workers. The quantitative determination was performed after eluting the spots. Phenylglyoxilic acid was measured at 255 nm and mandelic acid by derivative spectroscopically estimation of the .CH(OH).COOH -chromophore at 217 nm or by a three-wavelength mode, respectively. The recovery in urine was 80-104% for phenylglyoxilic acid and 99-105% for mandelic acid.

  15. Two-dimensional high-performance thin-layer chromatography of tryptic bovine albumin digest using normal- and reverse-phase systems with silanized silica stationary phase.

    Science.gov (United States)

    Gwarda, Radosław Łukasz; Dzido, Tadeusz Henryk

    2013-10-18

    Among many advantages of planar techniques, two-dimensional (2D) separation seems to be the most important for analysis of complex samples. Here we present quick, simple and efficient two-dimensional high-performance thin-layer chromatography (2D HPTLC) of bovine albumin digest using commercial HPTLC RP-18W plates (silica based stationary phase with chemically bonded octadecyl ligands of coverage density 0.5μmol/m(2) from Merck, Darmstadt). We show, that at low or high concentration of water in the mobile phase comprised methanol and some additives the chromatographic systems with the plates mentioned demonstrate normal- or reversed-phase liquid chromatography properties, respectively, for separation of peptides obtained. These two systems show quite different separation selectivity and their combination into 2D HPTLC process provides excellent separation of peptides of the bovine albumin digest. Copyright © 2013 Elsevier B.V. All rights reserved.

  16. Therapeutic drug monitoring of nevirapine in saliva in Uganda using high performance liquid chromatography and a low cost thin-layer chromatography technique.

    Science.gov (United States)

    Lamorde, Mohammed; Fillekes, Quirine; Sigaloff, Kim; Kityo, Cissy; Buzibye, Allan; Kayiwa, Joshua; Merry, Concepta; Nakatudde-Katumba, Lillian; Burger, David; de Wit, Tobias F Rinke

    2014-09-01

    In resource limited settings access to laboratory monitoring of HIV treatment is limited and therapeutic drug monitoring is generally unavailable. This study aimed to evaluate nevirapine concentrations in saliva using low-cost thin-layer chromatography (TLC) and nevirapine concentrations in plasma and saliva using high performance liquid chromatography (HPLC) methods; and to correlate nevirapine plasma concentrations to HIV treatment outcomes in Ugandan patients. Paired plasma and stimulated saliva samples were obtained from Ugandan, HIV-infected adults on nevirapine-based ART. Nevirapine concentrations were measured using a validated HPLC method and a novel TLC method. Plasma nevirapine concentrations HPLC were considered subtherapeutic. Negative/positive predictive values of different thresholds for subtherapeutic nevirapine concentrations in saliva were determined. Virologic testing and, if applicable, HIV drug resistance testing was performed. Median (interquartile range, IQR) age of 297 patients was 39.1 (32.8-45.2) years. Three hundred saliva and 287 plasma samples were available for analysis. Attempts failed to determine nevirapine saliva concentrations by TLC. Using HPLC, median (IQR) nevirapine concentrations in saliva and plasma were 3.40 (2.59-4.47) mg/L and 6.17 (4.79-7.96) mg/L, respectively. The mean (coefficient of variation,%) nevirapine saliva/plasma ratio was 0.58 (62%). A cut-off value of 1.60 mg/L nevirapine in saliva was associated with a negative/positive predictive value of 0.99/0.72 and a sensitivity/specificity of 87%/98% for predicting subtherapeutic nevirapine plasma concentrations, respectively. Only 5% (15/287) of patients had subtherapeutic nevirapine plasma concentrations, of which 3 patients had viral load results > 400 copies/mL. Patients with nevirapine concentrations in plasma 400 copies/mL). The low-cost TLC technique for monitoring nevirapine in saliva was unsuccessful but monitoring nevirapine saliva and plasma

  17. Preconcentration of rare earth elements from rocks by thin-layer chromatography and their neutron-activation determination

    International Nuclear Information System (INIS)

    Ryabukhin, V.A.; Volynets, M.P.; Myasoedov, B.F.

    1990-01-01

    Conditions were studied for separation of rare earths and accompanying elements in rocks on Fixion 50x8 thin-layer plates using solutions of oxalic acid and ammonium chloride in ammonia medium. A simple technique was developed for TLC proconcentration of rare earths followed by gamma spectrometric analysis of the irradiated fractions that enabled to determine 8-10 elements in samples with a mass of up to 30 mg. The limits of detection (μg/g) were 0.05 (Eu), 0.1 (Sm), 0.2 (Tb), 0.3 (Yb), 0.4 (La), 1.0 (Tu), 2.0 (Ce), 10 (Nd). The relative standard deviation was 0.05-0.20 at element levels 5-10 times as high as the detection limits

  18. Separation, identification and quantification of carotenoids and chlorophylls in dietary supplements containing Chlorella vulgaris and Spirulina platensis using High Performance Thin Layer Chromatography.

    Science.gov (United States)

    Hynstova, Veronika; Sterbova, Dagmar; Klejdus, Borivoj; Hedbavny, Josef; Huska, Dalibor; Adam, Vojtech

    2018-01-30

    In this study, 14 commercial products (dietary supplements) containing alga Chlorella vulgaris and cyanobacteria Spirulina platensis, originated from China and Japan, were analysed. UV-vis spectrophotometric method was applied for rapid determination of chlorophylls, carotenoids and pheophytins; as degradation products of chlorophylls. High Performance Thin-Layer Chromatography (HPTLC) was used for effective separation of these compounds, and also Atomic Absorption Spectrometry for determination of heavy metals as indicator of environmental pollution. Based on the results obtained from UV-vis spectrophotometric determination of photosynthetic pigments (chlorophylls and carotenoids), it was confirmed that Chlorella vulgaris contains more of all these pigments compared to the cyanobacteria Spirulina platensis. The fastest mobility compound identified in Chlorella vulgaris and Spirulina platensis using HPTLC method was β-carotene. Spectral analysis and standard calibration curve method were used for identification and quantification of separated substances on Thin-Layer Chromatographic plate. Quantification of copper (Cu 2+ , at 324.7 nm) and zinc (Zn 2+ , at 213.9nm) was performed using Flame Atomic Absorption Spectrometry with air-acetylene flame atomization. Quantification of cadmium (Cd 2+ , at 228.8 nm), nickel (Ni 2+ , at 232.0nm) and lead (Pb 2+ , at 283.3nm) by Electrothermal Graphite Furnace Atomic Absorption Spectrometry; and quantification of mercury (Hg 2+ , at 254nm) by Cold Vapour Atomic Absorption Spectrometry. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Quantitative determination of seven chemical constituents and chemo-type differentiation of chamomiles using high-performance thin-layer chromatography.

    Science.gov (United States)

    Sagi, Satyanarayanaraju; Avula, Bharathi; Wang, Yan-Hong; Zhao, Jianping; Khan, Ikhlas A

    2014-10-01

    A simple and rapid high-performance thin-layer chromatographic method was developed for the separation and determination of six flavonoids (rutin, luteolin-7-O-β-glucoside, chamaemeloside, apigenin-7-O-β-glucoside, luteolin, apigenin) and one coumarin, umbelliferone from chamomile plant samples and dietary supplements. The separation was achieved on amino silica stationary phase using dichloromethane/acetonitrile/ethyl formate/glacial acetic acid/formic acid (11:2.5:3:1.25:1.25 v/v/v/v/v) as the mobile phase. The quantitation of each compound was carried out using densitometric reflection/absorption mode at their respective absorbance maxima after postchromatographic derivatization using natural products reagent (1% w/v methanolic solution of diphenylboric acid-β-ethylamino ester). The method was validated for specificity, limits of detection and quantification, precision (intra- and interday) and accuracy. The limits of detection and quantification were found to be in the range from 6-18 and 16-55 ng/band for six flavonoids and one coumarin, respectively. The intra- and interday precision was found to be 90%. The data acquired from high-performance thin-layer chromatography was processed by principal component analysis using XLSTAT statistical software. Application of principal component analysis and agglomerative hierarchial clustering was successfully able to differentiate two chamomiles (German and Roman) and Chrysanthemum. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Development and validation of High-performance Thin-layer Chromatography Method for Simultaneous Determination of Polyphenolic Compounds in Medicinal Plants.

    Science.gov (United States)

    Jayachandran Nair, C V; Ahamad, Sayeed; Khan, Washim; Anjum, Varisha; Mathur, Rajani

    2017-12-01

    Quantitative standardization of plant-based products is challenging albeit essential to maintain their quality. This study aims to develop and validate high-performance thin-layer chromatography (HPTLC) method for the simultaneous determination of rutin (Ru), quercetin (Qu), and gallic acid (Ga) from Psidium guajava Linn. (PG) and Aegle marmelos (L.) Correa. (AM) and correlate with antioxidant activity. The stock solution (1 mg/mL) of standard Ru, Qu, and Ga in methanol: Water (1:1) was serially diluted and spotted (5 μL) on slica gel 60 F 254 thin-layer chromatography plates. Toluene: Ethyl acetate: Formic acid: Methanol (3:4:0.8:0.7, v/v/v) was selected as mobile phase for analysis at 254 nm. Hydroalcoholic (1:1) extracts of leaves of PG and AM were fractionated and similarly analyzed. Antioxidant activity was also determined using 2, 2-diphenyl-1-picrylhydrazyl assay. The developed method was robust and resolved Ru, Qu, and Ga at R f 0.08 ± 0.02, 0.76 ± 0.01, and 0.63 ± 0.02, respectively. The intra-day, interday precision, and interanalyst were limit of detection and limit of quantification for Ru, Qu, and Ga were 4.51, 4.2, 5.27, and 13.67, 12.73, 15.98 ng/spot, respectively. Antioxidant activity (Log 50% inhibition) of PG and AM was 4.947 ± 0.322 and 6.498 ± 0.295, respectively. The developed HPTLC method was rapid, accurate, precise, reproducible, and specific for the simultaneous estimation of Ru, Qu, and Ga. HPTLC method for simultaneous determination and quantification of Rutin, Quercetin and Gallic acid, is reported for quality control of herbal drugs. Abbreviations Used: A: Aqueous fraction; AM: Aegle marmelos L. Correa; B: Butanol fraction; C: Chloroform fraction; EA: Ethyl acetate fraction; Ga: Gallic acid; H: Hexane fraction; HA: Hydroalcoholic extract; HPTLC: High-performance thin-layer chromatography; PG: Psidium guajava ; Qu: Quercetin; Ru: Rutin.

  1. Thin-layer chromatography of 49 metal ions on stannic antimonate in aqueous and mixed solvent systems containing dimethylsulfoxide: quantitative separation of uranium from numerous metal ions

    International Nuclear Information System (INIS)

    Qureshi, M.; Varshney, K.G.; Rajput, R.P.S.

    1976-01-01

    Thin-layer chromatography of 40 metal ions in 31 aqueous and mixed solvent systems has been performed on stannic antimonate ion-exchange material. Dimethylsulfoxide has been utilized to resolve such binary mixtures as La 3+ and Ce 3+ from Pr 3+ , Nd 3+ , and Sm 3+ ; VO 2+ from Ti 4+ , Nb 5+ , and Ta 5+ ; Ga 3+ from In 3+ , Tl + , and Y 3+ ; Fe 3+ from VO 2+ ; and Mg 2+ from Al 3+ . Quantitative separation of 200 to 800 μg U from its binary mixtures and from the synthetic mixtures containing Mg 2+ , Bi 3+ , Fe 3+ , Th 4+ , Ce 4+ , Cr 3+ , Zr 4+ , Hf 4+ , Ti 4+ Mn 2+ , Cu 2+ , Ce 3+ , In 3+ , Y 3+ , Ca 2+ , Co 2+ , Tl + , Nb 5+ , and Ag + has been obtained

  2. A simple and rapid method for the determination of taxol produced by fungal endophytes from medicinal plants using high performance thin layer chromatography.

    Science.gov (United States)

    Gangadevi, V; Muthumary, J

    2008-01-01

    Taxol is an important anticancer drug used widely in the clinical field. In this study, some endophytic fungi were isolated from selected medicinal plants, and were screened for their potential in the production of taxol, using a rapid separation technique of high performance thin layer chromatography (HPTLC). Of the 20 screened fungi, only 13 fungal species produced taxol in the artificial culture medium. The results of HPTLC showed that the 13 fungal species had identical ultraviolet (UV) characteristics, positive reactivity with a spray reagent, yielding a blue spot, which turned to dark gray after 24 hours, and had Rf values identical to that of the authentic taxol. The amount of taxol was also quantified by comparing the peak area and the peak height of the fungal samples with those of authentic taxol.

  3. Development of Validated High-performance Thin-layer Chromatography Method for Simultaneous Determination of Quercetin and Kaempferol in Thespesia populnea.

    Science.gov (United States)

    Panchal, Hiteksha; Amin, Aeshna; Shah, Mamta

    2017-01-01

    Thespesia populnea L. (Family: Malvaceae) is a well-known medicinal plant distributed in tropical regions of the world and cultivated in South Gujarat and indicated to be useful in cutaneous affections, psoriasis, ringworm, and eczema. Bark and fruits are indicated in the diseases of skin, urethritis, and gonorrhea. The juice of fruits is employed in treating certain hepatic diseases. The plant is reported to contain flavonoids, quercetin, kaempferol, gossypetin, Kaempferol-3-monoglucoside, β-sitosterol, kaempferol-7-glucoside, and gossypol. T. populnea is a common component of many herbal and Ayurvedic formulation such as Kamilari and Liv-52. The present study aimed at developing validated and reliable high-performance thin layer chromatography (HPTLC) method for the analysis of quercetin and kaempferol simultaneously in T. populnea . The method employed thin-layer chromatography aluminum sheets precoated with silica gel as the stationary phase and toluene: ethyl acetate: formic acid (6:4:0.3 v/v/v) as the mobile phase, which gave compact bands of quercetin and kaempferol. Linear regression data for the calibration curves of standard quercetin and kaempferol showed a good linear relationship over a concentration range of 100-600 ng/spot and 500-3000 ng/spot with respect to the area and correlation coefficient (R2) was 0.9955 and 0.9967. The method was evaluated regarding accuracy, precision, selectivity, and robustness. Limits of detection and quantitation were recorded as 32.06 and 85.33 ng/spot and 74.055 and 243.72 ng/spot for quercetin and kaempferol, respectively. We concluded that this method employing HPTLC in the quantitative determination of quercetin and kaempferol is efficient, simple, accurate, and validated.

  4. Quantitative Determination of L-DOPA in Seeds of Mucuna Pruriens Germplasm by High Performance Thin Layer Chromatography.

    Science.gov (United States)

    Raina, Archana P; Khatri, Renu

    2011-07-01

    Mucuna pruriens Linn. is an important medicinal plant used for treatment of Parkinson's disease and many others in ancient Indian medical system. L-DOPA extracted from seeds of Mucuna is a constituent of more than 200 indigenous drug formulations and is more effective as drug than the synthetic counterpart. A densitometric high performance thin-layer chromatographic (HPTLC) method was developed for quantification of L-DOPA content present in the seeds extract. The method involves separation of L-DOPA on precoated silica gel 60 GF(254) HPTLC plates using a solvent system of n-butanol-acetic-acid-water (4:1:1, v/v) as the mobile phase. Quantification was done at 280 nm using absorbance reflectance mode. Linearity was found in the concentration range of 100 to 1000 ng/spot with the correlation coefficient value of 0.9980. The method was validated for accuracy, precision and repeatability. Mean recovery was 100.89%. The LOD and LOQ for L-DOPA determination were found to be 3.41 ng/spot and 10.35 ng/spot respectively. The proposed HPTLC method was found to be precise, specific and accurate for quantitative determination of L-DOPA. It can be used for rapid screening of large germplasm collections of Mucuna pruriens for L-DOPA content. The method was used to study variation in fifteen accessions of Mucuna germplasm collected from different geographical regions.

  5. Combined computational-experimental approach to predict blood-brain barrier (BBB) permeation based on "green" salting-out thin layer chromatography supported by simple molecular descriptors.

    Science.gov (United States)

    Ciura, Krzesimir; Belka, Mariusz; Kawczak, Piotr; Bączek, Tomasz; Markuszewski, Michał J; Nowakowska, Joanna

    2017-09-05

    The objective of this paper is to build QSRR/QSAR model for predicting the blood-brain barrier (BBB) permeability. The obtained models are based on salting-out thin layer chromatography (SOTLC) constants and calculated molecular descriptors. Among chromatographic methods SOTLC was chosen, since the mobile phases are free of organic solvent. As consequences, there are less toxic, and have lower environmental impact compared to classical reserved phases liquid chromatography (RPLC). During the study three stationary phase silica gel, cellulose plates and neutral aluminum oxide were examined. The model set of solutes presents a wide range of log BB values, containing compounds which cross the BBB readily and molecules poorly distributed to the brain including drugs acting on the nervous system as well as peripheral acting drugs. Additionally, the comparison of three regression models: multiple linear regression (MLR), partial least-squares (PLS) and orthogonal partial least squares (OPLS) were performed. The designed QSRR/QSAR models could be useful to predict BBB of systematically synthesized newly compounds in the drug development pipeline and are attractive alternatives of time-consuming and demanding directed methods for log BB measurement. The study also shown that among several regression techniques, significant differences can be obtained in models performance, measured by R 2 and Q 2 , hence it is strongly suggested to evaluate all available options as MLR, PLS and OPLS. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Highly sensitive on-site detection of drugs adulterated in botanical dietary supplements using thin layer chromatography combined with dynamic surface enhanced Raman spectroscopy.

    Science.gov (United States)

    Fang, Fang; Qi, Yunpeng; Lu, Feng; Yang, Liangbao

    2016-01-01

    The phenomenon of botanical dietary supplements (BDS) doped with illegal adulterants has become a serious problem all over the world, which could cause great threat to human's health. Therefore, it is of great value to identify BDS. Herein, we put forward a highly sensitive method for on-site detection of antitussive and antiasthmatic drugs adulterated in BDS using thin layer chromatography (TLC) combined with dynamic surface enhanced Raman spectroscopy (DSERS). Adulterants in BDS were separated on a TLC plate and located under UV illumination. Then DSERS detection was performed using a portable Raman spectrometer with 50% glycerol silver colloid serving as DSERS active substrate. Here, the effects of different solvents on detection efficacy were evaluated using phenformin hydrochloride (PHE) as a probe. It was shown that 50% glycerol resulted in higher SERS enhancement and relatively higher stability. Moreover, practical application of this novel TLC-DSERS method was demonstrated with rapid analysis of real BDS samples and one sample adulterated with benproperine phosphate (BEN) was found. Furthermore, the obtained result was verified by ultra performance liquid chromatography-quadrupole time of flight mass spectrometry (UPLC-QTOF/MS). The sensitivity of the TLC-DSERS technique is 1-2 orders of magnitude higher than that of TLC-SERS technique. The results turned out that this combined method would have good prospects for on-site and sensitive detection of adulterated BDS. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Analysis of Bioactive Components of Oilseed Cakes by High-Performance Thin-Layer Chromatography-(Bioassay Combined with Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Sue-Siang Teh

    2015-03-01

    Full Text Available Hemp, flax and canola seed cakes are byproducts of the plant oil extraction industry that have not received much attention in terms of their potential use for human food instead of animal feed. Thus, the bioactivity profiling of these oilseed cakes is of interest. For their effect-directed analysis, planar chromatography was combined with several (bioassays, namely 2,2-diphenyl-1-picrylhydrazyl scavenging, acetylcholine esterase inhibition, planar yeast estrogen screen, antimicrobial Bacillus subtilis and Aliivibrio fischeri assays. The streamlined high-performance thin-layer chromatography (HPTLC-bioassay method allowed the discovery of previously unknown bioactive compounds present in these oilseed cake extracts. In contrast to target analysis, the direct link to the effective compounds allowed comprehensive information with regard to selected effects. HPTLC-electrospray ionization-mass spectrometry via the elution-head based TLC-MS Interface was used for a first characterization of the unknown effective compounds. The demonstrated bioactivity profiling on the feed/food intake side may guide the isolation of active compounds for production of functional food or for justified motivation of functional feed/food supplements.

  8. Characterization of Mycobacterium paratuberculosis by gas-liquid and thin-layer chromatography and rapid demonstration of mycobactin dependence using radiometric methods

    International Nuclear Information System (INIS)

    Damato, J.J.; Knisley, C.; Collins, M.T.

    1987-01-01

    Thirty-six Mycobacterium paratuberculosis isolates of bovine, caprine, and ovine origins were evaluated by using gas-liquid chromatography (GLC), thin-layer chromatography (TLC), and BACTEC 7H12 Middlebrook TB medium in an effort to more rapidly differentiate this group of organisms from other mycobacteria. Bacterial suspensions (0.1 ml) were inoculated by syringe into 7H12 broth containing 2 micrograms of mycobactin P per ml and control broth without mycobactin P. Cultures were incubated at 37 0 C and read daily with a BACTEC Model 301. After 8 days of incubation, the growth index readings for the test broths containing mycobactin P were twice those of the control broths without mycobactin P. Sixty-five isolates of mycobacteria other than M. paratuberculosis were also examined. No difference was noted between the growth index readings of control and mycobactin-containing broths. Except for Mycobacterium avium-Mycobacterium intracellulare, TLC studies differentiated M. paratuberculosis from the other mycobacterial species tested. The GLC data reveal that all M. paratuberculosis isolates had a distinctive peak (14A) which was not found among M. avium-M. intracellulare complex organisms. These data indicate that 7H12 radiometric broth was able to rapidly demonstrate the mycobactin dependence of M. paratuberculosis and GLC and TLC procedures were capable of rapidly differentiating this organism from the other mycobacteria studied

  9. Extraction of oxytetracycline starting from the meats of chickens and identifications by thin layer chromatography; Extraction de l'oxytetracycline dans les viandes des poulet et identification par chromatographie sur couche mince

    Energy Technology Data Exchange (ETDEWEB)

    Elghozzi, Amira [Institut Superieur de Biotechnologie de Sidi Thabet (Tunisia)

    2007-07-01

    Use of antibiotics in the poultry also suspected as one of the cause of the emergence of resistance to antibiotics of some bacteria what causes risks on human health continuation of persistence of the residues in the foodstuffs. We were interested in detected the presence qualitatively of oxytetracyclin in samples of muscle and liver of chicken by the use of the techniques of thin layer chromatography. Although, These results are satisfactory, it is always necessary to prevent the dangers which cause the risks of the residues of oxytetracycline on health. (Author). 20 refs.

  10. Fractionation of Cardiolite for clinical use: comparative evaluation of radiochemical purity by thin-layer and paper chromatography of 99mTc-hexakis-2-methoxy-isobutyl-isonitrile complex

    International Nuclear Information System (INIS)

    Albernaz, M.S.; Pantoja, M.R.; Martinho, M.J.R.; Fonseca, M.L.B.; Bernardo-Filho, Mario

    1996-01-01

    Twenty-five vials of the previous divided Cardiolite (technetium-99m-hexakis-2-metoxi-isobutyl-isonitrile) were evaluated immediately after labeling with technetium-99m and in 15 them the specific activity assurance was checked at hourly intervals up to 3 hours. Quality control assessment comprised instant thin-layer chromatography, as suggested by the manufacturer, compared to paper chromatography which is widely available and less expensive than the former. Among the 25 bottles, 21 had a radiochemical purity higher than 89%. The redistribution of the Cardiolite in small doses vacuum containers was a practical and reliable technique. The technetium-99m-isonitrile was a stable radiochemical compound thought the three hours period of observation and proved adequate for clinical use. When thin-layer and paper chromatography were compared there was no significant difference regarding radiochemical purity. (author)

  11. Determination of caffeine, theobromine and theophylline in Mate beer and Mate soft drinks by high-performance thin-layer chromatography.

    Science.gov (United States)

    Oellig, Claudia; Schunck, Jacob; Schwack, Wolfgang

    2018-01-19

    Mate beer and Mate soft drinks are beverages produced from the dried leaves of Ilex paraguariensis (Yerba Mate). In Yerba Mate, the xanthine derivatives caffeine, theobromine and theophylline, also known as methylxanthines, are important active components. The presented method for the determination of caffeine, theobromine and theophylline in Mate beer and Mate soft drinks by high-performance thin-layer chromatography with ultraviolet detection (HPTLC-UV) offers a fully automated and sensitive determination of the three methylxanthines. Filtration of the samples was followed by degassing, dilution with acetonitrile in the case of Mate beers for protein precipitation, and centrifugation before the extracts were analyzed by HPTLC-UV on LiChrospher silica gel plates with fluorescence indicator and acetone/toluene/chloroform (4:3:3, v/v/v) as the mobile phase. For quantitation, the absorbance was scanned at 274nm. Limits of detection and quantitation were 1 and 4ng/zone, respectively, for caffeine, theobromine and theophylline. With recoveries close to 100% and low standard deviations reliable results were guaranteed. Experimental Mate beers as well as Mate beers and Mate soft drinks from the market were analyzed for their concentrations of methylxanthines. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Building blocks for the development of an interface for high-throughput thin layer chromatography/ambient mass spectrometric analysis: a green methodology.

    Science.gov (United States)

    Cheng, Sy-Chyi; Huang, Min-Zong; Wu, Li-Chieh; Chou, Chih-Chiang; Cheng, Chu-Nian; Jhang, Siou-Sian; Shiea, Jentaie

    2012-07-17

    Interfacing thin layer chromatography (TLC) with ambient mass spectrometry (AMS) has been an important area of analytical chemistry because of its capability to rapidly separate and characterize the chemical compounds. In this study, we have developed a high-throughput TLC-AMS system using building blocks to deal, deliver, and collect the TLC plate through an electrospray-assisted laser desorption ionization (ELDI) source. This is the first demonstration of the use of building blocks to construct and test the TLC-MS interfacing system. With the advantages of being readily available, cheap, reusable, and extremely easy to modify without consuming any material or reagent, the use of building blocks to develop the TLC-AMS interface is undoubtedly a green methodology. The TLC plate delivery system consists of a storage box, plate dealing component, conveyer, light sensor, and plate collecting box. During a TLC-AMS analysis, the TLC plate was sent to the conveyer from a stack of TLC plates placed in the storage box. As the TLC plate passed through the ELDI source, the chemical compounds separated on the plate would be desorbed by laser desorption and subsequently postionized by electrospray ionization. The samples, including a mixture of synthetic dyes and extracts of pharmaceutical drugs, were analyzed to demonstrate the capability of this TLC-ELDI/MS system for high-throughput analysis.

  13. Comparison and characterization of soybean and sunflower lecithins used for chocolate production by high-performance thin-layer chromatography with fluorescence detection and electrospray mass spectrometry.

    Science.gov (United States)

    Krüger, Stephanie; Bürmann, Laura; Morlock, Gertrud E

    2015-03-25

    The scarce availability of nongenetically modified soybeans on the world market represents a growing problem for food manufacturers. Hence, in this study the effects of substituting soybean with sunflower lecithin were investigated with regard to chocolate production. The glycerophospholipid pattern of the different lecithin samples was investigated by high-performance thin-layer chromatography fluorescence detection (HPTLC-FLD) and by HPTLC-positive ion electrospray ionization mass spectrometry (ESI(+)-MS) via the TLC-MS Interface and by scanning HPTLC-matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOFMS). Especially, the contents of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) were of interest due to the influencing effects of these two glycerophospholipids on the rheological parameters of chocolate production. The lecithin substitution led to only slight differences in the rheological parameters of milk and dark chocolate. Limits of detection (LODs) and limits of quantification (LOQs) of seven glycerophospholipids were studied for three detection modes. Mean LODs ranged from 8 to 40 mg/kg for HPTLC-FLD and, using a single-quadrupole MS, from 10 to 280 mg/kg for HPTLC-ESI(+)-MS as well as from 15 to 310 mg/kg for HPTLC-FLD-ESI(+)-MS recorded after derivatization with the primuline reagent.

  14. Analysis of biodiesel and biodiesel-petrodiesel blends by high performance thin layer chromatography combined with easy ambient sonic-spray ionization mass spectrometry.

    Science.gov (United States)

    Eberlin, Livia S; Abdelnur, Patricia V; Passero, Alan; de Sa, Gilberto F; Daroda, Romeu J; de Souza, Vanderlea; Eberlin, Marcos N

    2009-08-01

    High performance thin layer chromatography (HPTLC) combined with on-spot detection and characterization via easy ambient sonic-spray ionization mass spectrometry (EASI-MS) is applied to the analysis of biodiesel (B100) and biodiesel-petrodiesel blends (BX). HPTLC provides chromatographic resolution of major components whereas EASI-MS allows on-spot characterization performed directly on the HPTLC surface at ambient conditions. Constituents (M) are detected by EASI-MS in a one component-one ion fashion as either [M + Na](+) or [M + H](+). For both B100 and BX samples, typical profiles of fatty acid methyl esters (FAME) detected as [FAME + Na](+) ions allow biodiesel typification. The spectrum of the petrodiesel spot displays a homologous series of protonated alkyl pyridines which are characteristic for petrofuels (natural markers). The spectrum for residual or admixture oil spots is characterized by sodiated triglycerides [TAG + Na](+). The application of HPTLC to analyze B100 and BX samples and its combination with EASI-MS for on-spot characterization and quality control is demonstrated.

  15. Application of 2-Trichloromethylbenzimidazole in Analytical Chemistry: A Highly Selective Chromogenic Reagent for Thin-Layer Chromatography and Some Other Analytical Uses

    Directory of Open Access Journals (Sweden)

    Leszek Konopski

    2012-01-01

    Full Text Available 2-Trichloromethylbenzimidazole (TCMB was used as a chromogenic reagent in organic or inorganic analysis, mainly in thin-layer chromatography (TLC. In reactions of TCMB with some heteroaromatic nitrogen containing compounds, such as azines, azoles and benzazoles, a formation of high colored products occurred. For azines, the chromogenic reaction was highly regioselective, since the both adjacent α-positions versus the nitrogen atom(s must not be substituted. A TLC method of detection was developed. Thirty azines, azoles, and benzazoles were detected at the detection limit 10 ng to 1 μg. This method was also applied for detection of heteroaromatic pesticides, and the attempts to construct active and passive dosimeters for nicotine were made. In a prechromatographic reaction of aromatic o-diamines with methyl trichloroacetimidate, TCMB or its derivatives were formed in situ. Followed by TLC and visualization in pyridine vapors, this procedure was applied for detection of o-phenylenediamine derivatives. The reaction product of TCMB and pyridine (LI Complex was identified and fully characterized. Two different reaction mechanisms: with electron deficient basic heteroaromatic compounds, like pyridine, and with more acidic compounds, for example, pyrrole, were discussed. In aqueous solutions, the LI Complex may be also used as a new indicator for complexometric, adsorption and acid-base titration of inorganic compounds.

  16. Algerian mint species:high performance thin layer chromatography quantitative determination of rosmarinic acid and in vitro inhibitory effects on linoleic acid peroxidation

    Institute of Scientific and Technical Information of China (English)

    Brahmi Fatiha; Madani Khodir; Stvigny Caroline; Chibane Mohamed; Duez Pierre

    2014-01-01

    Objective: To determine the quantitative paremeters of rosmarinic acid in Algerian mints,Mentha spicata L. (M. spicata), Mentha pulegium L. and Mentha rotundifolia (L.) Huds by high performance thin layer chromatography (HPTLC)-densitometric method and screen the effects of these plant extracts on linoleic acid peroxidation.Methods:The analyses were performed on HPTLC silica gel 60 F254 plates with chloroform:acetone: formic acid (75:16.5:8.5, v/v) as the mobile phase. Rosmarinic acid was determined in UV at 365 nm and fluorescence at λexc 325 nm with a 550 nm filter, respectively. The effects of plants extracts on linoleic acid peroxidation were measured by an indirect in vitro colorimetric method.Results:Chromatographic resolution permitted reliable quantification in both measurement modes and calibration curves were linear in a range of 150-1000 ng/spot. M. spicata was found to contain significantly higher concentrations of rosmarinic acid. The densitometric quantification allowed the analysis of many samples in a short time with reasonable precision (total precision for Mentha spp extracts, 5.1% and 5.8% for UV and fluorescence detection, respectively). The HPTLC data, allied to assays of linoleic acid peroxidation prevention, suggested the potential of M. spicata (52% Trolox®equivalents) as a natural source for inhibitors of lipid peroxidation.Conclusions:Densitometry can be used for routine determination and quality control of rosmarinic acid in herbal and formulations containing Mentha species.

  17. Detection and Estimation of alpha-Amyrin, beta-Sitosterol, Lupeol, and n-Triacontane in Two Medicinal Plants by High Performance Thin Layer Chromatography

    Directory of Open Access Journals (Sweden)

    Saikat S. Mallick

    2014-01-01

    Full Text Available A normal phase high performance thin layer chromatography (HPTLC method has been developed and validated for simultaneous estimation of four components, namely, alpha-amyrin, beta-sitosterol, lupeol, and n-triacontane from two medicinally important plants, Leptadenia reticulata Wight & Arn. and Pluchea lanceolata (DC. CB. Clarke. In Ayurveda, both plants have been reported to possess immunomodulatory activity. Chromatographic separation of the four components from the methanolic extracts of whole plant powders of Leptadenia reticulata Wight & Arn. and Pluchea lanceolata (DC. CB. Clarke. was performed on TLC aluminium plates precoated with silica gel 60F254 using a suitable mobile phase. The densitometric scanning was done after derivatization at λ = 580 nm for α-amyrin, β-sitosterol, and lupeol, and at 366 nm for n-triacontane. The developed HPTLC method has been validated and used for simultaneous quantitation of the four components from the methanolic extracts of whole plant powders of Leptadenia reticulata Wight & Arn. and Pluchea lanceolata (DC. CB. Clarke. The developed HPTLC method is simple, rapid, and precise and can be used for routine quality control.

  18. Algerian mint species: high performance thin layer chromatography quantitative determination of rosmarinic acid and in vitro inhibitory effects on linoleic acid peroxidation

    Directory of Open Access Journals (Sweden)

    Brahmi Fatiha

    2014-12-01

    Full Text Available Objective: To determine the quantitative paremeters of rosmarinic acid in Algerian mints, Mentha spicata L. (M. spicata, Mentha pulegium L. and Mentha rotundifolia (L. Huds by high performance thin layer chromatography (HPTLC-densitometric method and screen the effects of these plant extracts on linoleic acid peroxidation. Methods: The analyses were performed on HPTLC silica gel 60 F254 plates with chloroform: acetone: formic acid (75:16.5:8.5, v/v as the mobile phase. Rosmarinic acid was determined in UV at 365 nm and fluorescence at λexc 325 nm with a 550 nm filter, respectively. The effects of plants extracts on linoleic acid peroxidation were measured by an indirect in vitro colorimetric method. Results: Chromatographic resolution permitted reliable quantification in both measurement modes and calibration curves were linear in a range of 150-1 000 ng/spot. M. spicata was found to contain significantly higher concentrations of rosmarinic acid. The densitometric quantification allowed the analysis of many samples in a short time with reasonable precision (total precision for Mentha spp extracts, 5.1% and 5.8% for UV and fluorescence detection, respectively. The HPTLC data, allied to assays of linoleic acid peroxidation prevention, suggested the potential of M. spicata (52% Trolox® equivalents as a natural source for inhibitors of lipid peroxidation. Conclusions: Densitometry can be used for routine determination and quality control of rosmarinic acid in herbal and formulations containing Mentha species.

  19. A separable surface-enhanced Raman scattering substrate modified with MIL-101 for detection of overlapping and invisible compounds after thin-layer chromatography development.

    Science.gov (United States)

    Zhang, Bin Bin; Shi, Yi; Chen, Hui; Zhu, Qing Xia; Lu, Feng; Li, Ying Wei

    2018-01-02

    By coupling surface-enhanced Raman spectroscopy (SERS) with thin-layer chromatography (TLC), a powerful method for detecting complex samples was successfully developed. However, in the TLC-SERS method, metal nanoparticles serving as the SERS-active substrate are likely to disturb the detection of target compounds, particularly in overlapping compounds after TLC development. In addition, the SERS detection of compounds that are invisible under both visible light and UV 254/365 after TLC development is still a significant challenge. In this study, we demonstrated a facile strategy to fabricate a TLC plate with metal-organic framework-modified gold nanoparticles as a separable SERS substrate, on which all separated components, including overlapping and invisible compounds, could be detected by a point-by-point SERS scan along the developing direction. Rhodamine 6G (R6G) was used as a probe to evaluate the performance of the substrate. The results indicated that the substrate provided good sensitivity and reproducibility, and optimal SERS signals could be collected in 5 s. Furthermore, this new substrate exhibited a long shelf life. Thus, our method has great potential for the sensitive and rapid detection of overlapping and invisible compounds in complex samples after TLC development. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

  20. Detection of tobacco-related biomarkers in urine samples by surface-enhanced Raman spectroscopy coupled with thin-layer chromatography.

    Science.gov (United States)

    Huang, Rongfu; Han, Sungyub; Li, Xiao Sheryl

    2013-08-01

    The nicotine metabolites, cotinine and trans-3'-hydroxycotinine (3HC) are considered as superior biomarkers for identifying tobacco exposure. More importantly, the ratio of 3HC to cotinine is a good indicator to phenotype individuals for cytochrome P450 2A6 activity and to individualize pharmacotherapy for tobacco addiction. In this paper, a simple, robust and novel method based on surface-enhanced Raman spectroscopy coupled with thin-layer chromatography (TLC) was developed to directly quantify the biomarkers in human urine samples. This is the first time surface-enhanced Raman spectroscopy (SERS) was used to detect cotinine and 3HC in urine samples. The linear dynamic range for the detection of cotinine is from 40 nM to 8 μM while that of 3HC is from 1 μM to 15 μM. The detection limits are 10 nM and 0.2 μM for cotinine and 3HC, respectively. The proposed method was further validated by quantifying the concentration of both cotinine and 3HC in smokers' urine samples. This TLC-SERS method allows the direct detection of cotinine in the urine samples of both active and passive smokers and the detection of 3HC in smokers.

  1. Rapid Biochemical Mixture Screening by Three-Dimensional Patterned Multifunctional Substrate with Ultra-Thin Layer Chromatography (UTLC) and Surface Enhanced Raman Scattering (SERS).

    Science.gov (United States)

    Lee, Bi-Shen; Lin, Pi-Chen; Lin, Ding-Zheng; Yen, Ta-Jen

    2018-01-11

    We present a three-dimensional patterned (3DP) multifunctional substrate with the functions of ultra-thin layer chromatography (UTLC) and surface enhanced Raman scattering (SERS), which simultaneously enables mixture separation, target localization and label-free detection. This multifunctional substrate is comprised of a 3DP silicon nanowires array (3DP-SiNWA), decorated with silver nano-dendrites (AgNDs) atop. The 3DP-SiNWA is fabricated by a facile photolithographic process and low-cost metal assisted chemical etching (MaCE) process. Then, the AgNDs are decorated onto 3DP-SiNWA by a wet chemical reduction process, obtaining 3DP-AgNDs@SiNWA multifunctional substrates. With various patterns designed on the substrates, the signal intensity could be maximized by the excellent confinement and concentrated effects of patterns. By using this 3DP-AgNDs@SiNWA substrate to scrutinize the mixture of two visible dyes, the individual target could be recognized and further boosted the Raman signal of target 15.42 times comparing to the un-patterned AgNDs@SiNWA substrate. Therefore, such a three-dimensional patterned multifunctional substrate empowers rapid mixture screening, and can be readily employed in practical applications for biochemical assays, food safety and other fields.

  2. Detection of structurally similar adulterants in botanical dietary supplements by thin-layer chromatography and surface enhanced Raman spectroscopy combined with two-dimensional correlation spectroscopy.

    Science.gov (United States)

    Li, Hao; Zhu, Qing xia; Chwee, Tsz sian; Wu, Lin; Chai, Yi feng; Lu, Feng; Yuan, Yong fang

    2015-07-09

    Thin-layer chromatography (TLC) coupled with surface enhanced Raman spectroscopy (SERS) has been widely used for the study of various complex systems, especially for the detection of adulterants in botanical dietary supplements (BDS). However, this method is not sufficient to distinguish structurally similar adulterants in BDS since the analogs have highly similar chromatographic and/or spectroscopic behaviors. Taking into account the fact that higher cost and more time will be required for comprehensive chromatographic separation, more efforts with respect to spectroscopy are now focused on analyzing the overlapped SERS peaks. In this paper, the combination of a TLC-SERS method with two-dimensional correlation spectroscopy (2DCOS), with duration of exposure to laser as the perturbation, is applied to solve this problem. Besides the usual advantages of the TLC-SERS method, such as its simplicity, rapidness, and sensitivity, more advantages are presented here, such as enhanced selectivity and good reproducibility, which are obtained by 2DCOS. Two chemicals with similar structures are successfully differentiated from the complex BDS matrices. The study provides a more accurate qualitative screening method for detection of BDS with adulterants, and offers a new universal approach for the analysis of highly overlapped SERS peaks. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Construction of a supercritical fluid extraction (SFE equipment: validation using annatto and fennel and extract analysis by thin layer chromatography coupled to image

    Directory of Open Access Journals (Sweden)

    Júlio Cezar Flores JOHNER

    2016-01-01

    Full Text Available Abstract The present work describes setting up a laboratory unit for supercritical fluid extraction. In addition to its construction, a survey of cost was done to compare the cost of the homemade unit with that of commercial units. The equipment was validated using an extraction of annatto seeds’ oil, and the extraction and fractionation of fennel oil were used to validate the two separators; for both systems, the solvent was carbon dioxide. The chemical profiles of annatto and fennel extracts were assessed using thin layer chromatography; the images of the chromatographic plates were processed using the free ImageJ software. The cost survey showed that the homemade equipment has a very low cost (~US$ 16,000 compared to commercial equipment. The extraction curves of annatto were similar to those obtained in the literature (yield of 3.8% oil. The separators were validated, producing both a 2.5% fraction of fennel seed extract rich in essential oils and another extract fraction composed mainly of oleoresins. The ImageJ software proved to be a low-cost tool for obtaining an initial evaluation of the chemical profile of the extracts.

  4. Effect-directed fingerprints of 77 botanical extracts via a generic high-performance thin-layer chromatography method combined with assays and mass spectrometry.

    Science.gov (United States)

    Krüger, S; Hüsken, L; Fornasari, R; Scainelli, I; Morlock, G E

    2017-12-22

    Quantitative effect-directed profiles of 77 industrially and freshly extracted botanicals like herbs, spices, vegetables and fruits, widely used as food ingredients, dietary supplements or traditional medicine, gave relevant information on their quality. It allows the assessment of food, dietary supplements and phytomedicines with regard to potential health-promoting activities. In contrary to sum parameter assays and targeted analysis, chromatography combined with effect-directed analysis allows fast assignment of single active compounds and evaluation of their contribution to the overall activity, originating from a food or botanical sample. High-performance thin-layer chromatography was hyphenated with UV/Vis/FLD detection and effect-directed analysis, using the 2,2-diphenyl-1-picrylhydrazyl radical, Gram-negative Aliivibrio fischeri, Gram-positive Bacillus subtilis, acetylcholinesterase and tyrosinase assays. Bioactive compounds of interest were eluted using an elution head-based interface and further characterized by electrospray ionization (high-resolution) mass spectrometry. This highly streamlined workflow resulted in a hyphenated HPTLC-UV/Vis/FLD-EDA-ESI + /ESI - -(HR)MS method. The excellent quantification power of the method was shown on three compounds. For rosmarinic acid, contents ranged from 4.5mg/g (rooibos) to 32.6mg/g (rosemary), for kaempferol-3-glucoside from 0.6mg/g (caraway) to 4.4mg/g (wine leaves), and for quercetin-3-glucoside from 1.1mg/g (hawthorn leaves) to 17.7mg/g (thyme). Three mean repeatabilities (%RSD) over 18 quantifications for the three compounds were ≤2.2% and the mean intermediate precision over three different days (%RSD, n=3) was 5.2%. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Slantingly cross loading sample system enables simultaneous performance of separation and mixture to detect molecular interactions on thin-layer chromatography.

    Science.gov (United States)

    Shimizu-Yumoto, Hiroko; Hayashi, Nobuyuki; Ichimura, Kazuo; Nakayama, Masayoshi

    2012-07-06

    Anthocyanins are major flower pigments that can be affected by copigments, colorless compounds that can modify anthocyanin coloration to more intense and bluer. Thin-layer chromatography (TLC) is an available technique to separate and analyze anthocyanins and copigments. To easily and comprehensively detect copigments, we added function of mixture of compounds to TLC; by slantingly cross loading samples on TLC, compounds are symmetrically developed at various angle lines from the upper origin to individual R(f) values and cross each other in an orderly fashion, where mixture is simultaneously performed with separation. Occurrence of copigments can be detected as a coloration change on the developed line of anthocyanin. Pink sweet pea (Lathyrus odoratus L.) petals were analyzed by the cross-TLC and a more intense spot and a paler spot on the anthocyanin line were detected. As each spot overlapped with an ultraviolet absorbance line, each of these ultraviolet absorption compounds was purified and identified as kaempferol 3-rhamnoside and 2-cyanoethyl-isoxazolin-5-one, respectively. Whereas kaempferol 3-rhamnoside is a flavonoid and had a general copigment effect of more intense and bluer coloration change, 2-cyanoethyl-isoxazolin-5-one is a compound whose structure is outside of conventional categories of copigments and had a novel effect to change anthocyanin coloration paler while maintaining color tone. We determined that the search for copigments should be carried out without pre-existing prediction of structures and effects. We have shown that slantingly cross loading samples system on plate-type chromatography is an effective technique for such comprehensive analysis of molecular interaction. Crown Copyright © 2012. Published by Elsevier B.V. All rights reserved.

  6. Lysergic acid amide as chemical marker for the total ergot alkaloids in rye flour - Determination by high-performance thin-layer chromatography-fluorescence detection.

    Science.gov (United States)

    Oellig, Claudia

    2017-07-21

    Ergot alkaloids are generally determined by high-performance liquid chromatography (HPLC) coupled to fluorescence detection (FLD) or mass selective detection, analyzing the individual compounds. However, fast and easy screening methods for the determination of the total ergot alkaloid content are more suitable, since for monitoring only the sum of the alkaloids is relevant. The herein presented screening uses lysergic acid amide (LSA) as chemical marker, formed from ergopeptine alkaloids, and ergometrine for the determination of the total ergot alkaloids in rye with high-performance thin-layer chromatography-fluorescence detection (HPTLC-FLD). An ammonium acetate buffered extraction step was followed by liquid-liquid partition for clean-up before the ergopeptine alkaloids were selectively transformed to LSA and analyzed by HPTLC-FLD on silica gel with isopropyl acetate/methanol/water/25% ammonium hydroxide solution (80:10:3.8:1.1, v/v/v/v) as the mobile phase. The enhanced native fluorescence of LSA and unaffected ergometrine was used for quantitation without any interfering matrix. Limits of detection and quantitation were 8 and 26μg LSA/kg rye, which enables the determination of the total ergot alkaloids far below the applied quality criterion limit for rye. Close to 100% recoveries for different rye flours at relevant spiking levels were obtained. Thus, reliable results were guaranteed, and the fast and efficient screening for the total ergot alkaloids in rye offers a rapid alternative to the HPLC analysis of the individual compounds. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. The offline combination of thin-layer chromatography and high-performance liquid chromatography with diode array detection and micrOTOF-Q mass spectrometry for the separation and identification of spinochromes from sea urchin (Strongylocentrotus droebachiensis) shells.

    Science.gov (United States)

    Shikov, Alexander N; Ossipov, Vladimir I; Martiskainen, Olli; Pozharitskaya, Olga N; Ivanova, Svetlana A; Makarov, Valery G

    2011-12-16

    Thin-layer chromatography (TLC) with off-line high-performance liquid chromatography coupled to diode array detection and micrOTOF-Q mass spectrometry (HPLC-DAD-MS) resulted in the successful fractionation, separation and identification of spinochrome pigments from sea urchin (Strongylocentrotus droebachiensis) shells. Two fractions of pigments were separated by TLC and eluted with methanol using a TLC-MS interface. HPLC-DAD-MS analysis of the fractions indicated the presence of six sea urchin pigments: spinochrome monomers B and D, three spinochrome dimers (anhydroethylidene-6,6'-bis(2,3,7-trihydroxynaphthazarin) and its isomer and ethylidene-6,6'-bis(2,3,7-trihydroxynaphthazarin)), and one pigment that was preliminary identified as a spinochrome dimer with the structural formula C(22)H(16)O(16). Copyright © 2011 Elsevier B.V. All rights reserved.

  8. Densitometric Validation and Optimisation of Polyphenols in Ocimum sanctum Linn by High Performance Thin-layer Chromatography.

    Science.gov (United States)

    U K, Ilyas; Katare, Deepshikha P; Aeri, Vidhu

    2015-01-01

    Ocimum sanctum Linn (Sanskrit: Tulasi; family: Libiaceae), popularly known as holy basil or Ocimum teinufolium, is found throughout the semitropical and tropical parts of India. In Ayurveda, Tulasi has been well known for its therapeutic potentials. To optimise and develop a standard method to quantify seven polyphenols simultaneously by HPTLC. A three-level factor Box-Behnken statistical design was used for optimisation, where extraction time (min), temperature (°C) and methanol:water ratio (% v/v) are the independent variables with polyphenols as the dependent variable. The separation was archived on a silica-gel 60 F254 HPTLC plate using toluene:ethyl acetate:formic acid:methanol (3:3:0.8:0.2 v/v) as the mobile phase. Densitometric analysis of polyphenols was carried out in the absorbance mode at 366 nm. The quantification of polyphenols was carried out based on peak area with a linear calibration curve at concentration ranges of 60-240, 20-200, 100-1600, 40-200, 200-1400, 10-160, 200-1400, 100-5000 ng/band for caffeic acid, ellagic acid, rutin, kaempferol, catechin, quercetin, eupalitin and epicatechin respectively. The method was validated for peak purity, precision, accuracy, limit of detection (LOD) and quantification (LOQ). Method specificity was confirmed using the retention factor value and visible spectra correlation of marker compounds. A validated HPTLC method was newly developed for simultaneous quantification of seven polyphenols in an Ayurvedic preparation of O. sanctum. The proposed method is simple, precise, specific, accurate, cost-effective, less time consuming and has the ability to separate the polyphenols from other constituents. Copyright © 2015 John Wiley & Sons, Ltd.

  9. A thin-layer chromatography method for the identification of three different olibanum resins (Boswellia serrata, Boswellia papyrifera and Boswellia carterii, respectively, Boswellia sacra).

    Science.gov (United States)

    Paul, Michael; Brüning, Gerit; Bergmann, Jochen; Jauch, Johann

    2012-01-01

    Resins of the genus Boswellia are currently an interesting topic for pharmaceutical research since several pharmacological activities (e.g. anti-inflammatory, anti-microbial, anti-tumour) are reported for extracts and compounds isolated from them. Unambiguous identification of these resins, by simple and convenient analytical methods, has so far not clearly been verified. For differentiation and identification of three important Boswellia species (Boswellia serrata Roxb., Boswellia papyrifera Hochst. and Boswellia carterii Birdw., respectively Boswellia sacra Flueck.), possible even for minimally equipped laboratories, a thin-layer chromatography (TLC) method was developed, allowing unambiguous identification of the three species. Crude resin samples (commercial samples and a voucher specimen) were extracted with methanol or diethyl ether and subjected to TLC analysis (normal phase). A pentane and diethyl ether (2:1) with 1% acetic acid eluent was used. Chromatograms were analysed by UV detection (254 nm) and dyeing with anisaldehyde dyeing reagent. Significant spots were isolated and structures were assigned (mass spectrometry; nuclear magnetic resonance spectroscopy). Incensole and incensole acetate are specific biomarkers for Boswellia papyrifera. Boswellia carterii/Boswellia sacra reveal ß-caryophyllene oxide as a significant marker compound. Boswellia serrata shows neither incensole acetate nor ß-caryophyllene oxide spots, but can be identified by a strong serratol and a sharp 3-oxo-8,24-dien-tirucallic acid spot. The TLC method developed allows unambiguous identification of three different olibanum samples (Boswellia papyrifera, Boswellia serrata, Boswellia carterii/Boswellia sacra). Evidence on the specific biosynthesis routes of these Boswellia species is reported. Copyright © 2011 John Wiley & Sons, Ltd.

  10. Normal Raman and surface enhanced Raman spectroscopic experiments with thin layer chromatography spots of essential amino acids using different laser excitation sources

    Science.gov (United States)

    István, Krisztina; Keresztury, Gábor; Szép, Andrea

    2003-06-01

    A comparative study of the feasibility and efficiency of Raman spectroscopic detection of thin layer chromatography (TLC) spots of some weak Raman scatterers (essential amino acids, namely, glycine and L-forms of alanine, serine, valine, proline, hydroxyproline, and phenylalanine) was carried out using four different visible and near-infrared (NIR) laser radiations with wavelengths of 532, 633, 785, and 1064 nm. Three types of commercial TLC plates were tested and the possibility of inducing surface enhanced Raman scattering (SERS) by means of Ag-sol was also investigated. The spectra obtained from spotted analytes adsorbed on TLC plates were of very different quality strongly depending on the excitation wavelength, the wetness of the samples, and the compounds examined. The best results were obtained with the simple silica TLC plate, and it has been established that the longest wavelength (lowest energy) NIR excitation of a Nd:YAG laser is definitely more suitable for generating normal Raman scattering of analyte spots than any of the visible radiations. Concerning SERS with application of Ag-sol to the TLC spots, 1-3 orders of magnitude enhancement was observed with wet samples, the greatest with the 532 nm radiation and gradually smaller with the longer wavelength excitations. It is shown, however, that due to severe adsorption-induced spectral distortions and increased sensitivity to microscopic inhomogeneity of the sample, none of the SERS spectra obtained with the dispersive Raman microscope operating in the visible region were superior to the best NIR normal FT-Raman spectra, as far as sample identification is concerned.

  11. Toward rapid analysis, forecast and discovery of bioactive compounds from herbs by jointly using thin layer chromatography and ratiometric surface-enhanced Raman spectroscopy technique.

    Science.gov (United States)

    Gu, Xiaoling; Jin, Yang; Dong, Fang; Cai, Yueqing; You, Zhengyi; You, Junhui; Zhang, Liying; Du, Shuhu

    2018-05-10

    Conventional isolation and identification of active compounds from herbs have been extensively reported by using various chromatographic and spectroscopic techniques. However, how to quickly discover new bioactive ingredients from natural sources still remains a challenging task due to the interference of their similar structures or matrices. Here, we present a grand approach for rapid analysis, forecast and discovery of bioactive compounds from herbs based on a hyphenated strategy of thin layer chromatography and ratiometric surface-enhanced Raman spectroscopy. The performance of the hyphenated strategy is first evaluated by analyzing four protoberberine alkaloids, berberine (BER), coptisine (COP), palmatine (PAT) and jatrorrhizine (JAT), from a typical herb Coptidis Rhizoma as an example. It has been demonstrated that this coupling method can identify the four compounds by characteristic peaks at 728, 708, 736 and 732 cm -1 , and especially discriminate BER and COP (with similar migration distances) by ratiometric Raman intensity (I 708 /I 728 ). The corresponding limits of detection are 0.1, 0.05, 0.1 and 0.5 μM, respectively, which are about 1-2 orders of magnitude lower than those of direct observation method under 254 nm UV lamp. Based on these findings, the proposed method further guides forecast and discovery of unknown compounds from traditional Chinese herb Typhonii Rhizoma. Results infer that two trace alkaloids (BER and COP) from the n-butanol extract of Typhonii Rhizoma are found for the first time. Moreover, in vitro experiments manifest that BER can effectively decrease the viability of human glioma U87 cells by inducing cell cycle arrest in a concentration-dependent manner. Copyright © 2018 Elsevier B.V. All rights reserved.

  12. Anti-inflammatory activity and qualitative analysis of different extracts of Maytenus obscura (A. Rich.) Cuf. by high performance thin layer chromatography method

    Institute of Scientific and Technical Information of China (English)

    Mohamed F. Alajmi; Perwez Alam

    2014-01-01

    Objective: To perform aqueous ethanol soluble fraction (AESF) and dichloromethane extract of aerial parts of Maytenus obscura (A. Rich.) Cuf. using high performance thin layer chromatography (HPTLC) and to test anti-inflammatory activity of these extracts.Methods:HPTLC studies were carried out using CAMAG HPTLC system equipped with Linomat IV applicator, TLC scanner 3, Reprostar 3, CAMAG ADC 2 and WIN CATS-4 software were used. The anti-inflammatory activity was tested by injecting different groups of rats (6 each) with formalin in hind paw and measuring the edema volume before and 1 h later formalin injection. Control group received saline i.p. The extracts treatment was injected i.p. in doses of 100 and 200 mg/kg 1 h before formalin administration. Indomethacin (30 mg/kg) was used as standard.Results:The results of preliminary phytochemical studies confirmed the presence of protein, lipid, carbohydrate, phenol, flavonoid, saponin, triterpenoid, alkaloid and anthraquinone in both extracts. Chromatography was performed on glass-backed silica gel 60 F254 HPTLC plates with the green solvents toluene: ethyacetate: glacial acetic acid (5:3:0.2, v/v/v) as mobile phase. HPTLC finger printing of AESF revealed major eight peaks with Rf values in the range of 0.28 to 0.80 and the dichloromethane revealed major 11 peaks with Rf values in the range of 0.12 to 0.76. The purity of sample was confirmed by comparing the absorption spectra at start, middle and end position of the band. Treatment of rats (i.p.) with AESF and dichloromethane in doses of 100 and 200 mg/kg inhibited singnificantly (P<0.05, n=6) formalin-induced inflammation by 50%, 55.9%, 45.5%, and 51.4%, respectively.Conclusions:HPTLC finger printing of AESF and dichloromethane of Maytenus obscura revealed eight major spots for alcoholic extracts and nine major spots for dichloromethane extracts. These HPTLC profiles may be of great usefulness in the quality control of herbal products containing these extracts. The

  13. Chemical variability along the value chains of turmeric (Curcuma longa): a comparison of nuclear magnetic resonance spectroscopy and high performance thin layer chromatography.

    Science.gov (United States)

    Booker, Anthony; Frommenwiler, Debora; Johnston, Deborah; Umealajekwu, Chinenye; Reich, Eike; Heinrich, Michael

    2014-03-14

    Herbal medicine value chains have generally been overlooked compared with food commodities. Not surprisingly, revenue generation tends to be weighted towards the end of the chain and consequently the farmers and producers are the lowest paid beneficiaries. Value chains have an impact both on the livelihood of producers and on the composition and quality of products commonly sold locally and globally and consequently on the consumers. In order to understand the impact of value chains on the composition of products, we studied the production conditions for turmeric (Curcuma longa) and the metabolomic composition of products derived from it. We aimed at integrating these two components in order to gain a better understanding of the effect of different value chains on the livelihoods of some producers. This interdisciplinary project uses a mixed methods approach. Case studies were undertaken on two separate sites in India. Data was initially gathered on herbal medicine value chains by means of semi-structured interviews and non-participant observations. Samples were collected from locations in India, Europe and the USA and analysed using (1)H NMR spectroscopy coupled with multivariate analysis software and with high performance thin layer chromatography (HPTLC). We investigate medicinal plant value chains and interpret the impact different value chains have on some aspects of the livelihoods of producers in India and, for the first time, analytically assess the chemical variability and quality implications that different value chains may have on the products available to end users in Europe. There are benefits to farmers that belonged to an integrated chain and the resulting products were subject to a higher standard of processing and storage. By using analytical methods, including HPTLC and (1)H NMR spectroscopy, it has been possible to correlate some variations in product composition for selected producers and identify strengths and weaknesses of some types of value

  14. Stable, Microfabricated Thin Layer Chromatography Plates without Volume Distortion on Patterned, Carbon and Al2O3-Primed Carbon Nanotube Forests

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, David S.; Kanyal, Supriya S.; Gupta, Vipul; Vail, Michael A.; Dadson, Andrew; Engelhard, Mark H.; Vanfleet, Richard; Davis, Robert C.; Linford, Matthew R.

    2012-09-28

    In a recent report (Song, J.; et al., Advanced Functional Materials 2011, 21, 1132-1139) some of us described the fabrication of thin layer chromatography (TLC) plates from patterned carbon nanotube (CNT) forests, which were directly infiltrated/coated with silicon by low pressure chemical vapor deposition (LPCVD) of silicon using SiH4. Following infiltration, the nanotubes were removed from the assemblies and the silicon simultaneously converted to SiO2 in a high temperature oxidation step. However, while straightforward, this process had some shortcomings, not the least of which was some distortion of the lithographically patterned features during the volume expansion that accompanied oxidation. Herein we overcome theis issue and also take substantial steps forward in the microfabrication of TLC plates by showing: (i) A new method for creating an adhesion promotion layer on CNT forests by depositing a few nanometers of carbon followed by atomic layer deposition (ALD) of Al2O3. This method for appears to be new, and X-ray photoelectron spectroscopy confirms the expected presence of oxygen after carbon deposition. ALD of Al2O3 alone and in combination with the carbon on patterned CNT forests was also explored as an adhesion promotion layer for CNT forest infiltration. (ii) Rapid, conformal deposition of an inorganic material that does not require subsequent oxidation: fast pseudo-ALD growth of SiO2 via alumina catalyzed deposition of tris(tert-butoxy)silanol onto the carbon/Al2O3-primed CNT forests. (iii) Faithful reproduction of the features in the masks used to microfabricate the TLC plates (M-TLC) this advance springs from the previous two points. (iv) A bonded (amino) phase on a CNT-templated microfabricated TLC plate. (v) Fast, highly efficient (125,000 - 225,000 N/m) separations of fluorescent dyes on M-TLC plates. (vi) Extensive characterization of our new materials by TEM, SEM, EDAX, DRIFT, and XPS. (vii) A substantially lower process temperature for the

  15. The importance of thin layer chromatography and UV microspectrophotometry in the analysis of reactive dyes released from wool and cotton fibers.

    Science.gov (United States)

    Wiggins, Kenneth G; Holness, Julie-Ann; March, Bridget M

    2005-03-01

    Samples of reactively-dyed wool and cotton were obtained from a range of dye manufacturers, dye distributors and the Forensic Science Service (FSS) Fibre Data Collection. The wool fibers were red in color and had previously been compared using comparison microscopy (CM), visible range microspectrophotometry (VS) and thin layer chromatography (TLC). The cotton fibers were blue and black in color and had not been previously compared. Red, blue and black fibers were chosen because they are often encountered in casework. The usage of reactive dyes to color fibers has increased over the last 10-15 years and these are often seen in casework. Before techniques were available that allowed reactively-dyed fibers to be compared using TLC only CM and microspectrophotometry were routinely carried out. Many laboratories, who had a microspectrophotometer, only had a visible range instrument. It was therefore important to see which techniques provide additional information, that gives greater individuality to fibers, to that obtained from CM. The color was released from the wool and cotton fibres using alkaline hydrolysis and a cellulase enzyme respectively. Many of the red wool samples were differentiated from each other using CM. More differentiation was found using VS and even more when ultraviolet range microspectrophotometry (UV) or TLC was used. Two samples could only be differentiated using TLC because CM, VS and UV failed to separate them. The black cotton samples were predominately differentiated using CM but VS allowed for further differentiation. With the samples used in this project UV and TLC failed to separate the samples further. The blue cotton samples benefited from the use of CM, VS and either UV or TLC to reduce the number of matching pairs. All techniques aided differentiation although with this set TLC and UV proved to be complementary techniques. Results demonstrate that TLC and UV both yield important information over and above that obtained from CM and VS

  16. Separation of paralytic shellfish poisoning toxins on Chromarods-SIII by thin-layer chromatography with the Iatroscan (mark 5) and flame thermionic detection.

    Science.gov (United States)

    Indrasena, W M; Ackman, R G; Gill, T A

    1999-09-10

    Thin-layer chromatography (TLC) on Chromarods-SIII with the Iatroscan (Mark-5) and a flame thermionic detector (FTID) was used to develop a rapid method for the detection of paralytic shellfish poisoning (PSP) toxins. The effect of variation in hydrogen (H2) flow, air flow, scan time and detector current on the FTID peak response for both phosphatidylcholine (PC) and PSP were studied in order to define optimum detection conditions. A combination of hydrogen and air flow-rates of 50 ml/min and 1.5-2.0 l/min respectively, along with a scan time of 40 s/rod and detector current of 3.0 A (ampere) or above were found to yield the best results for the detection of PSP compounds. Increasing the detector current level to as high as 3.3 A gave about 130 times more FTID response than did flame ionization detection (FID), for PSP components. Quantities of standards as small as 1 ng neosaxitoxin (NEO), 5 ng saxitoxin (STX), 5 ng B1-toxins (B1), 2 ng gonyautoxin (GTX) 2/3, 6 ng GTX 1/4 and 6 ng C-toxins (C1/C2) could be detected with the FTID. The method detection limits for toxic shellfish tissues using the FTID were 0.4, 2.1, 0.8 and 2.5 micrograms per g tissue for GTX 2/3, STX, NEO and C toxins, respectively. The FTID response increased with increasing detector current and with increasing the scan time. Increasing hydrogen and air flow-rates resulted in decreasing sensitivity within defined limits. Numerous solvent systems were tested, and, solvent consisting of chloroform: methanol-water-acetic acid (30:50:8:2) could separate C toxins from GTX, which eluted ahead of NEO and STX. Accordingly, TLC/FTID with the Iatroscan (Mark-5) seems to be a promising, relatively inexpensive and rapid method of screening plant and animal tissues for PSP toxins.

  17. Determination of Four Major Saponins in Skin and Endosperm of Seeds of Horse Chestnut (Aesculus Hippocastanum L.) Using High Performance Liquid Chromatography with Positive Confirmation by Thin Layer Chromatography.

    Science.gov (United States)

    Abudayeh, Zead Helmi Mahmoud; Al Azzam, Khaldun Mohammad; Naddaf, Ahmad; Karpiuk, Uliana Vladimirovna; Kislichenko, Viktoria Sergeevna

    2015-11-01

    To separate and quantify four major saponins in the extracts of the skin and the endosperm of seeds of horse chestnut (Aesculus hippocastanum L.) using ultrasonic solvent extraction followed by a high performance liquid chromatography-diode array detector (HPLC-DAD) with positive confirmation by thin layer chromatography (TLC). The saponins: escin Ia, escin Ib, isoescin Ia and isoescin Ib were extracted using ultrasonic extraction method. The optimized extraction conditions were: 70% methanol as extraction solvent, 80 °C as extraction temperature, and the extraction time was achieved in 4 hours. The HPLC conditions used: Zorbax SB-ODS-(150 mm × 2.1 mm, 3 μm) column, acetonitrile and 0.10% phosphoric acid solution (39:61 v/v) as mobile phase, flow rate was 0.5 mL min(-1) at 210 nm and 230 nm detection. The injection volume was 10 μL, and the separation was carried out isothermally at 30 °C in a heated chamber. The results indicated that the developed HPLC method is simple, sensitive and reliable. Moreover, the content of escins in seeds decreased by more than 30% in endosperm and by more than 40% in skin upon storage for two years. This assay can be readily utilized as a quality control method for horse chestnut and other related medicinal plants.

  18. Preparation of bone-implants by coating hydroxyapatite nanoparticles on self-formed titanium dioxide thin-layers on titanium metal surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Wijesinghe, W.P.S.L.; Mantilaka, M.M.M.G.P.G.; Chathuranga Senarathna, K.G. [Department of Chemistry, Faculty of Science, University of Peradeniya, 20400 Peradeniya (Sri Lanka); Postgraduate Institute of Science, University of Peradeniya, 20400 Peradeniya (Sri Lanka); Herath, H.M.T.U. [Postgraduate Institute of Science, University of Peradeniya, 20400 Peradeniya (Sri Lanka); Department of Medical Laboratory Science, Faculty of Allied Health Sciences, University of Peradeniya, 20400 Peradeniya (Sri Lanka); Premachandra, T.N. [Department of Veterinary Pathobiology, Faculty of Veterinary Medicine, University of Peradeniya, 20400 Peradeniya (Sri Lanka); Ranasinghe, C.S.K. [Department of Chemistry, Faculty of Science, University of Peradeniya, 20400 Peradeniya (Sri Lanka); Postgraduate Institute of Science, University of Peradeniya, 20400 Peradeniya (Sri Lanka); Rajapakse, R.P.V.J. [Postgraduate Institute of Science, University of Peradeniya, 20400 Peradeniya (Sri Lanka); Department of Veterinary Pathobiology, Faculty of Veterinary Medicine, University of Peradeniya, 20400 Peradeniya (Sri Lanka); Rajapakse, R.M.G., E-mail: rmgr@pdn.ac.lk [Department of Chemistry, Faculty of Science, University of Peradeniya, 20400 Peradeniya (Sri Lanka); Postgraduate Institute of Science, University of Peradeniya, 20400 Peradeniya (Sri Lanka); Edirisinghe, Mohan; Mahalingam, S. [Department of Mechanical Engineering, University College London, London WC1E 7JE (United Kingdom); Bandara, I.M.C.C.D. [School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, 2 George Street, Brisbane 4001, QLD (Australia); Singh, Sanjleena [Central Analytical Research Facility, Institute of Future Environments, Queensland University of Technology, 2 George Street, Brisbane 4001, QLD (Australia)

    2016-06-01

    Preparation of hydroxyapatite coated custom-made metallic bone-implants is very important for the replacement of injured bones of the body. Furthermore, these bone-implants are more stable under the corrosive environment of the body and biocompatible than bone-implants made up of pure metals and metal alloys. Herein, we describe a novel, simple and low-cost technique to prepare biocompatible hydroxyapatite coated titanium metal (TiM) implants through growth of self-formed TiO{sub 2} thin-layer (SFTL) on TiM via a heat treatment process. SFTL acts as a surface binder of HA nanoparticles in order to produce HA coated implants. Colloidal HA nanorods prepared by a novel surfactant-assisted synthesis method, have been coated on SFTL via atomized spray pyrolysis (ASP) technique. The corrosion behavior of the bare and surface-modified TiM (SMTiM) in a simulated body fluid (SBF) medium is also studied. The highest corrosion rate is found to be for the bare TiM plate, but the corrosion rate has been reduced with the heat-treatment of TiM due to the formation of SFTL. The lowest corrosion rate is recorded for the implant prepared by heat treatment of TiM at 700 °C. The HA-coating further assists in the passivation of the TiM in the SBF medium. Both SMTiM and HA coated SMTiM are noncytotoxic against osteoblast-like (HOS) cells and are in high-bioactivity. The overall production process of bone-implant described in this paper is in high economic value. - Highlights: • Colloidal hydroxyapatite nanorods are prepared by a novel method. • Surfaces of titanium metal plates are modified by self-forming TiO{sub 2} thin-films. • Prostheses are prepared by coating hydroxyapatite on surface modified Ti metal. • Bioactivity and noncytotoxicity are increased with surface modifications.

  19. Preparation of bone-implants by coating hydroxyapatite nanoparticles on self-formed titanium dioxide thin-layers on titanium metal surfaces

    International Nuclear Information System (INIS)

    Wijesinghe, W.P.S.L.; Mantilaka, M.M.M.G.P.G.; Chathuranga Senarathna, K.G.; Herath, H.M.T.U.; Premachandra, T.N.; Ranasinghe, C.S.K.; Rajapakse, R.P.V.J.; Rajapakse, R.M.G.; Edirisinghe, Mohan; Mahalingam, S.; Bandara, I.M.C.C.D.; Singh, Sanjleena

    2016-01-01

    Preparation of hydroxyapatite coated custom-made metallic bone-implants is very important for the replacement of injured bones of the body. Furthermore, these bone-implants are more stable under the corrosive environment of the body and biocompatible than bone-implants made up of pure metals and metal alloys. Herein, we describe a novel, simple and low-cost technique to prepare biocompatible hydroxyapatite coated titanium metal (TiM) implants through growth of self-formed TiO_2 thin-layer (SFTL) on TiM via a heat treatment process. SFTL acts as a surface binder of HA nanoparticles in order to produce HA coated implants. Colloidal HA nanorods prepared by a novel surfactant-assisted synthesis method, have been coated on SFTL via atomized spray pyrolysis (ASP) technique. The corrosion behavior of the bare and surface-modified TiM (SMTiM) in a simulated body fluid (SBF) medium is also studied. The highest corrosion rate is found to be for the bare TiM plate, but the corrosion rate has been reduced with the heat-treatment of TiM due to the formation of SFTL. The lowest corrosion rate is recorded for the implant prepared by heat treatment of TiM at 700 °C. The HA-coating further assists in the passivation of the TiM in the SBF medium. Both SMTiM and HA coated SMTiM are noncytotoxic against osteoblast-like (HOS) cells and are in high-bioactivity. The overall production process of bone-implant described in this paper is in high economic value. - Highlights: • Colloidal hydroxyapatite nanorods are prepared by a novel method. • Surfaces of titanium metal plates are modified by self-forming TiO_2 thin-films. • Prostheses are prepared by coating hydroxyapatite on surface modified Ti metal. • Bioactivity and noncytotoxicity are increased with surface modifications.

  20. Thin layer activation

    International Nuclear Information System (INIS)

    Schweickert, H.; Fehsenfeld, P.

    1995-01-01

    The reliability of industrial equip ment is substantially influenced by wear and corrosion; monitoring can prevent accidents and avoid down-time. One powerful tool is thin layer activation analysis (TLA) using accelerator systems. The information is used to improve mechanical design and material usage; the technology is used by many large companies, particularly in the automotive industry, e.g. Daimler Benz. A critical area of a machine component receives a thin layer of radioactivity by irradiation with charged particles from an accelerator - usually a cyclotron. The radioactivity can be made homogeneous by suitable selection of particle, beam energy and angle of incidence. Layer thickness can be varied from 20 microns to around 1 mm with different depth distributions; the position and size of the wear zone can be set to within 0.1 mm. The machine is then reassembled and operated so that wear can be measured. An example is a combustion engine comprising piston ring, cylinder wall, cooling water jacket and housing wall, where wear measurements on the cylinder wall are required in a critical zone around the dead-point of the piston ring. Proton beam bombardment creates a radioactive layer whose thickness is known accurately, and characteristic gamma radiation from this radioactive zone penetrates through the engine and is detected externally. Measurements can be made either of the activity removed from the surface, or of the (reduced) residual activity; wear measurement of the order of 10 -9 metres is possible

  1. High room-temperature figure of merit of thin layers prepared by laser ablation from Bi2Te3 target

    International Nuclear Information System (INIS)

    Walachova, J.; Zeipl, R.; Zelinka, J.; Malina, V.; Pavelka, M.; Jelinek, M.; Studnicka, V.; Lost'ak, P.

    2005-01-01

    The figure of merit ZT is measured by a Harman method on simple devices prepared on single thermoelectric layers of different thicknesses. The thermoelectric layers are prepared at different conditions by laser ablation from Bi 2 Te 3 target. The best measured figure of merit ZT is for our devices ZT=2.65. This result is comparable with the results obtained on superlattices. ZT oscillated with the thickness of the layers. On some devices the Seebeck coefficient is measured and using conductivity measurements along the thermoelectric layers the thermal conductivity is estimated from ZT. The low thermal conductivity of samples is explained by the quantum size effect and by existence of few phases of type Bi 2(m+n) Te 3n in the thermoelectric layers

  2. Preparation of bone-implants by coating hydroxyapatite nanoparticles on self-formed titanium dioxide thin-layers on titanium metal surfaces.

    Science.gov (United States)

    Wijesinghe, W P S L; Mantilaka, M M M G P G; Chathuranga Senarathna, K G; Herath, H M T U; Premachandra, T N; Ranasinghe, C S K; Rajapakse, R P V J; Rajapakse, R M G; Edirisinghe, Mohan; Mahalingam, S; Bandara, I M C C D; Singh, Sanjleena

    2016-06-01

    Preparation of hydroxyapatite coated custom-made metallic bone-implants is very important for the replacement of injured bones of the body. Furthermore, these bone-implants are more stable under the corrosive environment of the body and biocompatible than bone-implants made up of pure metals and metal alloys. Herein, we describe a novel, simple and low-cost technique to prepare biocompatible hydroxyapatite coated titanium metal (TiM) implants through growth of self-formed TiO2 thin-layer (SFTL) on TiM via a heat treatment process. SFTL acts as a surface binder of HA nanoparticles in order to produce HA coated implants. Colloidal HA nanorods prepared by a novel surfactant-assisted synthesis method, have been coated on SFTL via atomized spray pyrolysis (ASP) technique. The corrosion behavior of the bare and surface-modified TiM (SMTiM) in a simulated body fluid (SBF) medium is also studied. The highest corrosion rate is found to be for the bare TiM plate, but the corrosion rate has been reduced with the heat-treatment of TiM due to the formation of SFTL. The lowest corrosion rate is recorded for the implant prepared by heat treatment of TiM at 700 °C. The HA-coating further assists in the passivation of the TiM in the SBF medium. Both SMTiM and HA coated SMTiM are noncytotoxic against osteoblast-like (HOS) cells and are in high-bioactivity. The overall production process of bone-implant described in this paper is in high economic value. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Identification of Ginkgo biloba supplements adulteration using high performance thin layer chromatography and ultra high performance liquid chromatography-diode array detector-quadrupole time of flight-mass spectrometry.

    Science.gov (United States)

    Avula, Bharathi; Sagi, Satyanarayanaraju; Gafner, Stefan; Upton, Roy; Wang, Yan-Hong; Wang, Mei; Khan, Ikhlas A

    2015-10-01

    Ginkgo biloba is one of the most widely sold herbal supplements and medicines in the world. Its popularity stems from having a positive effect on memory and the circulatory system in clinical studies. As ginkgo popularity increased, non-proprietary extracts were introduced claiming to have a similar phytochemical profile as the clinically tested extracts. The standardized commercial extracts of G. biloba leaf used in ginkgo supplements contain not less than 6% sesquiterpene lactones and 24% flavonol glycosides. While sesquiterpene lactones are unique constituents of ginkgo leaf, the flavonol glycosides are found in many other botanical extracts. Being a high value botanical, low quality ginkgo extracts may be subjected to adulteration with flavonoids to meet the requirement of 24% flavonol glycosides. Chemical analysis by ultra high performance liquid chromatography-mass spectrometry revealed that adulteration of ginkgo leaf extracts in many of these products is common, the naturally flavonol glycoside-rich extract being spiked with pure flavonoids or extracts made from another flavonoid-rich material, such as the fruit/flower of Japanese sophora (Styphnolobium japonicum), which also contains the isoflavone genistein. Recently, genistein has been proposed as an analytical marker for the detection of adulteration of ginkgo extracts with S. japonicum. This study confirms that botanically authenticated G. biloba leaf and extracts made therefrom do not contain genistein, and the presence of which even in trace amounts is suggestive of adulteration. In addition to the mass spectrometric approach, a high performance thin layer chromatography method was developed as a fast and economic method for chemical fingerprint analysis of ginkgo samples.

  4. Correlation between dried blood spot thin layer chromatography and plasma high performance liquid chromatography of leucine/isoleucine levels among Filipino patients with maple syrup urine disease (MSUD) seen at the Institute of Human Genetics, National Institutes of Health

    International Nuclear Information System (INIS)

    Yaplito-Lee, Joy; Chiong, Mary Anne D.; Rana, Michelle D.; Rama, Kahlil Izza D.; David-Padilla, Carmencita; Cavan, Barbra Charina; Cordero, Cynthia P.

    2008-01-01

    Management of patients with maple syrup urine disease (MSUD) includes a low protein diet, supplemented with special formulas and constant monitoring of branched chain amino acids (BCAA). The gold standard for monitoring BCAA is plasma amino acid analysis using high performance liquid chromatography (HPLC). In a developing country like the Philippines, however, the cost of this test is prohibitive to the majority of the patients. In our center, dried blood spot leucine/isoleucine (leu/ile) levels analysed by thin layer chromatography (TLC) is often used to diagnose and monitor these patients. This study was done to determine the correlation of leu/ile levels using the two methods (TLC and HPLC). A total of 46 MSUD patients were referred to the Biochemical Genetics Laboratory of the Institute of Human Genetics (IHG) from July 2001 to January 2004. Thirty five samples were obtained from 18 of these patients (some patients were seen at IHG more than once), and paired determinations of plasma amino acid using TLC and HPLC were made. The remaining samples were either hemolyzed or were not analyzed. The correlation coefficient [rho denoted as ρ] was estimated at a 95% confidence level using the Fisher's Z transformation. Of the 18 patients, 12 were males. The youngest was 1 day old and the oldest was 5 years old. The majority had the classical type of MSUD and dietary protein was restricted to between 0.6 gram/kg/day to 1 gram/kg/day of natural protein. Using the first pairs of observation for these 18 patients, the correlation coefficient was 0.76 (95% C1:0.462 to 0.907). This suggest a strong correlation between the two methods. It is recommended that further studies be done to determine the potential of the dried blood spot leu/ile level by TLC as an alternative method that can be used in the diagnosis and monitoring of MSUD patients especially in a developing country. (Author)

  5. Thin-layer chromatography of ternary complexes of group-IIIA metals with 2-thenoyltrifluoroacetone and 2,2'-bipyridyl on cellulose layer

    Energy Technology Data Exchange (ETDEWEB)

    Chao, H E; Saitoh, K; Suzuki, N [Tohoku Univ., Sendai (Japan). Faculty of Science

    1980-11-11

    Normal phase thin-layer chromatographic behaviour of several ternary complexes of group-IIIA metals with 2-thenoyltrifluoroacetone (TTA) and 2,2'bipyridyl (bpy) has been investigated on cellulose layer. The ternary complexes of lanthanide metals show higher mutual separability than the complexes with TTA alone. Mutual separation of TTA complexes with La(III), Ce(III), Eu(III) or Y(III), Sc(III), Th(IV), and U(VI) has been successfully achieved by two-dimensional TLC, primarily with carbon tetrachloride-benzene (75:25) containing 0.02M TTA, and secondary with carbon tetrachloride-hexane (35:65) containing both 0.02M TTA and 0.02M bpy.

  6. Effects of Different Levels of Echinostoma caproni Miracidial Dose on Glucose and Maltose Composition of Biomphalaria glabrata Snails as Determined by High Performance Thin-Layer Chromatography-Densitometry

    Directory of Open Access Journals (Sweden)

    Dolcie DeGrandchamp

    2015-04-01

    Full Text Available The effects of 5, 25, and 40 Echinostoma caproni miracidia on the sugar content of young adult and mature adult Biomphalaria glabrata were studied using high performance thin layer chromatography (HPTLC-densitometry. Analysis was done on the snail’s digestive gland gonad complex (DGG at two and four weeks postmiracidial exposure. The sugars were extracted from the DGG using 70% ethanol and analyzed on silica gel HPTLC plates with a preadsorbent zone using 1-butanol-glacial acetic acid-diethyl ether-deionized water (27:18:5:3 mobile phase. The separated bands were then detected using alpha-naphthol-sulfuric reagent and quantified by densitometry at 515 nm. Significant differences were found in the maltose content between two and four weeks post exposure for both age groups. Additionally, significantly lower maltose and glucose levels were observed in the high exposure groups of both ages.

  7. 薄层色谱法检测海州常山桐树叶中肾上腺素的含量%Identification and quantification of adrenaline from the leaves of Clerodendrum phlomidis using thin-layer chromatography

    Institute of Scientific and Technical Information of China (English)

    Muthu Kumaradoss Mohan Maruga Raja; Ruchi Sureshbhai Patel; Shri Hari Mishra

    2011-01-01

    @@ In the Ayurvedic, Siddha and other medical systems of India, products derived from herbs,used either as active ingredients or as adjuvants,hold paramount importance as alternative medi-cines.However, their standardization poses a great challenge.Correct identification of these drugs is often problematic in both their complete form as well as in powder form, since these medicinal plants are known by a variety of vernacular names and frequently many medicinal plants share the same name.Comparative thin-layer chromatography (co-TLC) with chemical or biological marker compounds can be used to standardize raw materials.Moreover, due to its simplicity, accuracy, cost effectiveness and rapidity, TLC is often used as an alternative to other chromatographic tech-niques for quantifying plant products.

  8. Ad-hoc surface-enhanced Raman spectroscopy methodologies for the detection of artist dyestuffs: thin layer chromatography-surface enhanced Raman spectroscopy and in situ on the fiber analysis.

    Science.gov (United States)

    Brosseau, Christa L; Gambardella, Alessa; Casadio, Francesca; Grzywacz, Cecily M; Wouters, Jan; Van Duyne, Richard P

    2009-04-15

    Tailored ad-hoc methods must be developed for successful identification of minute amounts of natural dyes on works of art using Surface-Enhanced Raman Spectroscopy (SERS). This article details two of these successful approaches using silver film over nanosphere (AgFON) substrates and silica gel coupled with citrate-reduced Ag colloids. The latter substrate functions as the test system for the coupling of thin-layer chromatography and SERS (TLC-SERS), which has been used in the current research to separate and characterize a mixture of several artists' dyes. The poor limit of detection of TLC is overcome by coupling with SERS, and dyes which co-elute to nearly the same spot can be distinguished from each other. In addition, in situ extractionless non-hydrolysis SERS was used to analyze dyed reference fibers, as well as historical textile fibers. Colorants such as alizarin, purpurin, carminic acid, lac dye, crocin, and Cape jasmine were thus successfully identified.

  9. Determination of the recognition site for adenine-specific methylase of Shigella sonnei 47 by hydazinolysis of DNA, followed by separation of the purine oligonucleotides by thin-layer chromatography on DEAE-cellulose

    International Nuclear Information System (INIS)

    Lopatina, N.G.; Kirnos, M.D.; Suchkov, S.V.; Vanyushin, B.F.; Nikol'skaya, I.I.; Debov, S.S.

    1985-01-01

    A method has been developed for the separation of oligopurine units according to length and composition by two-dimensional thin-layer chromatography on plates with DEAE-cellulose, permitting a comparative analysis of the content of various purine isopliths in DNA of different origin. In the case of the analysis of methylated DNA, the method permits a comparison of the substrate specificity of various enzymes of methylation of the adenine residues in DNA. In conjunction with enzymatic treatment of labeled methylated isopliths, the method permits determination of the methylatable sequence and in a number of cases an ascertainment of the recognition site for adenine-specific methylase as a whole. The proposed method was used to establish the fact that the methylase Ssol recognizes the sequence 5'...G-A-A-T-T-C...3' and methylates the adenine residue closest to its 5'-end

  10. Physicochemical, thin layer and gas-liquid chromatographic ...

    African Journals Online (AJOL)

    DELL

    2012-05-22

    May 22, 2012 ... PEG (3 m × 3 mm I. D.) was used for gas chromatography. Physicochemical analysis ... subjected to thin layer chromatography on plates (20 × 20 cm) having 0.25 mm thick silica gel ..... Headspace solid- phase microextraction ...

  11. Thin-layer chromatographic technique for rapid detection of bacterial phospholipases.

    Science.gov (United States)

    Legakis, N J; Papavassiliou, J

    1975-11-01

    Silica gel thin-layer chromatography was employed to detect lecithinase activity induced from bacterial resting cell preparations induced from bacterial resting cell preparations incubated at 37 C for 4 h in the presence of purified egg yolk lecithin. Bacillus subtilis, Bacillus cereus, Serratia marcescens, and Pseudomonas aeruginosa hydrolyzed lecithin with the formation of free fatty acids as the sole lipid-soluble product. In none of the Escherichia coli and Citrobacter freundii strains tested could lecithinase activity be detected. Four among eight strains of Enterobacter aerogenes and one among 12 strains of Proteus tested produced negligible amounts of free fatty acid.

  12. Cromatografia em camada delgada para o diagnóstico da intoxicação por aldicarb ("chumbinho" em cães e gatos Thin-layer chromatography for aldicarb poisoning diagnosis in dogs and cats

    Directory of Open Access Journals (Sweden)

    F.G. Xavier

    2007-10-01

    Full Text Available Avaliou-se a cromatografia em camada delgada (CCD como método de diagnóstico toxicológico para os casos de intoxicação por aldicarb em cães e gatos, utilizando-se 50 amostras de conteúdo gástrico obtidas durante a necropsia e 50 amostras de alimentos utilizados como iscas para intoxicar criminalmente os animais. Todas as amostras resultaram positivas para o aldicarb, mostrando ser a CCD uma técnica qualitativa eficiente, rápida e de baixo custo, com uso potencial na toxicologia veterinária forense.The present study concerns about the identification of aldicarb residues using thin-layer chromatography (TLC in 50 samples of gastric content obtained from the necropsy of dogs and cats and 50 samples of foods suspected of being used as baits. All samples resulted positive for aldicarb showing that the TLC is an efficient, fast and not expensive qualitative method for the detection of aldicarb, being useful for this purpose in the forensic veterinary toxicology.

  13. Development and evaluation of thin-layer chromatography-digital image-based analysis for the quantitation of the botanical pesticide azadirachtin in agricultural matrixes and commercial formulations: comparison with ELISA.

    Science.gov (United States)

    Tanuja, Penmatsa; Venugopal, Namburi; Sashidhar, Rao Beedu

    2007-01-01

    A simple thin-layer chromatography-digital image-based analytical method has been developed for the quantitation of the botanical pesticide, azadirachtin. The method was validated by analyzing azadirachtin in the spiked food matrixes and processed commercial pesticide formulations, using acidified vanillin reagent as a postchromatographic derivatizing agent. The separated azadirachtin was clearly identified as a green spot. The Rf value was found to be 0.55, which was similar to that of a reference standard. A standard calibration plot was established using a reference standard, based on the linear regression analysis [r2 = 0.996; y = 371.43 + (634.82)x]. The sensitivity of the method was found to be 0.875 microg azadirachtin. Spiking studies conducted at the 1 ppm (microg/g) level in various agricultural matrixes, such as brinjal, tomato, coffee, and cotton seeds, revealed the recoveries of azadirachtin in the range of 67-92%. Azadirachtin content of commercial neem formulations analyzed by the method was in the range of 190-1825 ppm (microg/mL). Further, the present method was compared with an immunoanalytical method enzyme-linked immonosorbent assay developed earlier in our laboratory. Statistical comparison of the 2 methods, using Fischer's F-test, indicated no significant difference in variance, suggesting that both methods are comparable.

  14. Determination of ferulic acid and related compounds by thin layer ...

    African Journals Online (AJOL)

    The analysis of certain phenolic compounds from plants, and their chemical transformation with microorganisms or isolated enzymes, has application in the food and pharmaceutical industry. The rapid quantitative estimation of ferulic acid by thin layer chromatography is described by measurement of the area of the ...

  15. Comparison of two detection methods in thin layer chromatographic ...

    African Journals Online (AJOL)

    o-tolidine plus potassium iodide and photosynthesis inhibition detection methods were investigated for the analysis of three triazine herbicides (atrazine, ametryne, simazine) and two urea herbicides (diuron, metobromuron) in a coastal savanna soil using thin layer chromatography to compare the suitability of the two ...

  16. Physicochemical properties of silica gel coated with a thin layer of polyaniline (PANI) and its application in non-suppressed ion chromatography.

    Science.gov (United States)

    Sowa, Ireneusz; Kocjan, Ryszard; Wójciak-Kosior, Magdalena; Swieboda, Ryszard; Zajdel, Dominika; Hajnos, Mieczysław

    2013-10-15

    Physicochemical properties of a new sorbent and its potential application in non-suppressed ion chromatography (IC) have been investigated. The sorbent was obtained in a process of covering silica gel particles with a film of polyaniline (PANI). The properties of silica modified with polyaniline such as particle size, porosity, average quantity of polyaniline covering carrier and density of sorbent were determined. In our study the following methods were used: microscopic analysis, laser diffraction technique, combustion analysis, mercury porosimetry and helium pycnometry. Column with the newly obtained packing was used for the separation of inorganic anions. Optimized chromatographic system was successfully employed for analysis of iodide and bromide in selected pharmaceutical products (Bochnia salt and Iwonicz salt) applied in chronic respiratory disease. Analysis was carried out using 0.1M solution of HCl in mixture of methanol/water (50:50v/v) as a mobile phase; the flow rate was 0.3 mL min(-1), temperature was 24°C and λ=210 nm. Validation parameters such as correlation coefficient, RSD values, recovery, detection and quantification limits were found to be satisfactory. Copyright © 2013 Elsevier B.V. All rights reserved.

  17. Use of thin layer chromatography for the determination of radiochemical purity of radiopharmaceuticals in nuclear medicine services of Paraiba and Rio Grande do Norte, Brazil; Utilizacao da cromatografia em camada delgada para determinacao da pureza radioquimica de radiofarmacos em servicos de medicina nuclear da Paraiba e Rio Grande do Norte, Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, W.G.; Santos, P.A.L.; Lima, F.R.A. [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Programa de Pos-Graduacao em Tecnologia Energetica; Lima, F.F., E-mail: wellington.gandrade@gmail.com [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil)

    2012-07-01

    The paper chromatography and the thin layer chromatography are separation techniques in which the radioactive components migrate because of their affinity with the eluent (mobile phase) or stationary phase, respectively. In radiopharmaceuticals labeled with {sup 99m}Tc, besides its own radiopharmaceutical, {sup 99m}TcO{sup 4-} free and TcO{sub 2} can be identified and quantified. The evaluation of radiochemical purity of radiopharmaceuticals is essential to produce images free of artifacts as well as avoid unnecessary absorbed dose to the patient. Once they are managed in humans it is important and necessary that they undergo to strict quality control. Because of this, ANVISA in its 'Resolucao da Diretoria Colegiada (RDC) 38 of June 4th, 2008 states the obligation of performing a minimum of tests in nuclear medicine services routine prior to human administration. This work evaluated, by the method of thin layer chromatography (TLC), radiochemical purity, determined the pH of the radiopharmaceutical DEXTRAN- 500, DMSA, DTPA, PHYTATE, MDP, MIBI and Sn-Col used in nuclear medicine services in the states of Paraiba and Rio Grande do Norte - Brazil. The results show that the use of thin layer chromatography (TLC) as a standard method in routine of nuclear medicine services is possible, because it provides important data for the evaluation of radiochemical purity, allowing the exclusion of a radiopharmaceutical poorly marked. (author)

  18. Simultaneous Detection of Three Phosphodiesterase Type 5 Inhibitors and Eight of Their Analogs in Lifestyle Products and Screening for Adulterants by High-Performance Thin-Layer Chromatography.

    Science.gov (United States)

    Do, Tiên T K; Theocharis, Grigorios; Reich, Eike

    2015-01-01

    An HPTLC method is proposed to permit effective screening for the presence of three phosphodiesterase type 5 inhibitors (PDE5-Is; sildenafil, vardenafil, and tadalafil) and eight of their analogs (hydroxyacetildenafil, homosildenafil, thiohomosildenafil, acetildenafil, acetaminotadalafil, propoxyphenyl hydroxyhomosildenafil, hydroxyhomosildenafil, and hydroxythiohomosildenafil) in finished products, including tablets, capsules, chocolate, instant coffee, syrup, and chewing gum. For all the finished products, the same simple sample preparation may be applied: ultrasound-assisted extraction in 10 mL methanol for 30 min followed by centrifugation. The Rf values of individual HPTLC bands afford preliminary identification of potential PDE5-Is. Scanning densitometry capabilities enable comparison of the unknown UV spectra with those of known standard compounds and allow further structural insight. Mass spectrometric analysis of the material derived from individual zones supplies an additional degree of confidence. Significantly, the proposed screening technique allows focus on the already known PDE5 Is and provides a platform for isolation and chemical categorization of the newly-synthesized analogs. Furthermore, the scope could be expanded to other therapeutic categories (e.g., analgesics, antidiabetics, and anorexiants) that are occasionally coadulterated along with the PDE5-Is. The method was successfully applied to screening of 45 commercial lifestyle products. Of those, 31 products tested positive for at least one illegal component (sildenafil, tadalafil, propoxyphenyl hydroxyhomosildenafil, or dimethylsildenafil).

  19. Multi-Instrument Characterization of the Surfaces and Materials in Microfabricated, Carbon Nanotube-Templated Thin Layer Chromatography Plates. An Analogy to ‘The Blind Men and the Elephant’

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, David S.; Kanyal, Supriya S.; Madaan, Nitesh; Hancock, Jared M.; Dadson, Andrew; Vail, Michael A.; Vanfleet, Richard; Shutthanandan, V.; Zhu, Zihua; Engelhard, Mark H.; Linford, Matthew R.

    2013-08-08

    Herein we apply a suite of surface/materials analytical tools to characterize some of the materials created in the production of microfabricated thin layer chromatography plates. Techniques used include X-ray photoelectron spectroscopy (XPS), valence band spectroscopy, static time-of-flight secondary ion spectrometry (ToF-SIMS) in both positive and negative ion modes, Rutherford backscattering spectroscopy (RBS), and helium ion microscopy (HIM). Materials characterized include: the Si(100) substrate with native oxide: Si/SiO2, alumina (35 nm) deposited as a diffusion barrier on the Si/SiO2: Si/SiO2/Al2O3, iron (6 nm) thermally evaporated on the Al2O3: Si/SiO2/Al2O3/Fe, the iron film annealed in H2 to make Fe catalyst nanoparticles: Si/SiO2/Al2O3/Fe(NP), and carbon nanotubes (CNTs) grown from the Fe nanoparticles: Si/SiO2/Al2O3/Fe(NP)/CNT. The Fe thin films and nanoparticles are found in an oxidized state. Some of the analyses of the CNTs/CNT forests reported appear to be unique: the CNT forest appears to exhibit an interesting ‘channeling’ phenomenon by RBS, we observe an odd-even effect in the ToF-SIMS spectra of Cn- species for n = 1 – 6, with ions at even n showing greater intensity than the neighboring signals, and ions with n ≥ 6 showing a steady decrease in intensity, and valence band characterization of CNTs using X-radiation is reported. The information obtained from the combination of the different analytical tools provides a more complete understanding of our materials than a single technique, which is analogous to the story of ‘The Blind Men and the Elephant’. (Of course there is increasing emphasis on the use of multiple characterization tools in surface and materials analysis.) The raw XPS and ToF-SIMS spectra from this study will be submitted to Surface Science Spectra for archiving.

  20. Design of preparative-supercritical fluid chromatography.

    Science.gov (United States)

    Rajendran, Arvind

    2012-08-10

    Preparative supercritical fluid chromatography (prep-SFC) is an important separation process in the chromatographers toolbox. Owing to the unique properties of the mobile phase, which is predominantly CO(2), the behavior of SFC is markedly different from high performance liquid chromatography (HPLC). This review article focuses on the scale-up of preparative chromatography. The basics of SFC, with particular focus on highlighting the key differences between SFC and HPLC, are introduced. Then, a framework for rational design of prep-SFC is proposed. This framework is based on obtaining basic system parameters from analytical scale equipment, i.e., with very small amount of material, and performing design and optimization in silico to evaluate process performance and to identify operating conditions for scale-up. The tools required to obtain the input parameters such as adsorption isotherms are discussed and the development of the design and optimization framework is elaborated. Examples from the literature which use this approach for successful scale-up are provided. Finally the design of multi-column SFC systems is discussed. Copyright © 2012 Elsevier B.V. All rights reserved.

  1. High-performance thin-layer chromatography analysis of steviol glycosides in Stevia formulations and sugar-free food products, and benchmarking with (ultra) high-performance liquid chromatography.

    Science.gov (United States)

    Morlock, Gertrud E; Meyer, Stephanie; Zimmermann, Benno F; Roussel, Jean-Marc

    2014-07-11

    A high-performance TLC (HPTLC) method was newly developed and validated for analysis of 7 steviol glycosides in 6 different types of food and Stevia formulations. After a minimized one-step sample preparation, 21 samples were developed in parallel, allowing an effective food screening. Depending on the sample application volume, the method was suited to analyze food sample concentrations in the mg/kg range. LOQs of stevioside in natural yoghurt matrix spiked at 0.02, 0.13 and 0.2% were determined by the calibration curve method to be 12ng/band (peak height). ANOVA was successfully passed to prove data homogeneity in the working range (30-600ng/band). The accuracy (recovery tolerance limit, 92-120%), repeatability (3.1-5.4%) and intermediate precision (4.0-8.4%) were determined for stevioside in milk-based matrix including sample preparation and recovery rates at 3 different concentration levels. For the first time, the recording of HPTLC-ESI-MS spectra via the TLC-MS Interface was demonstrated for rebaudioside A. HPTLC contents for rebaudioside A were compared with results of two (U)HPLC methods. The running costs and analysis time of the three different methods were discussed in detail with regard to screening of food products. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Thin-layer electrochemistry of ferrocenylbenzene derivatives: Intramolecular electronic communication

    International Nuclear Information System (INIS)

    Wang, Michael C.P.; Li Yunchao; Merbouh, Nabyl; Yu, Hua-Zhong

    2008-01-01

    Three arylferrocene derivatives, ferrocenylbenzene (MFcB), 1,3-diferrocenylbenzene (DFcB), and 1,3,5-triferrocenylbenzene (TFcB), were prepared and their redox properties systematically explored by thin-layer cyclic voltammetry (CV) and differential-pulse voltammetry (DPV). In contrast to conventional CV measurements that produced only a single pair of redox waves for all three compounds, the thin-layer technique discriminated between the multistep electron-transfer processes of DFcB and TFcB. In particular, two and three pairs of symmetric peaks were observed, respectively, when CV curves were recorded at a graphite electrode coated with a DFcB-containing and a TFcB-containing thin film of nitrobenzene and immersed in aqueous sodium perchlorate solution. These results demonstrate that the ferrocenyl moieties attached to the meta-positions of a benzene ring communicate electronically with each other, as a result of their distinct face-to-face orientations

  3. Thin layers in actinide research

    International Nuclear Information System (INIS)

    Gouder, T.

    1998-01-01

    Surface science research at the ITU is focused on the synthesis and surface spectroscopy studies of thin films of actinides and actinide compounds. The surface spectroscopies used are X-ray and ultra violet photoelectron spectroscopy (XPS and UPS, respectively), and Auger electron spectroscopy (AES). Thin films of actinide elements and compounds are prepared by sputter deposition from elemental targets. Alloy films are deposited from corresponding alloy targets and could be used, in principle, as replicates of these targets. However, there are deviations between alloy film and target composition, which depend on the deposition conditions, such as pressure and target voltage. Mastering of these effects may allow us to study stoichiometric film replicates instead of thick bulk compounds. As an example, we discuss the composition of U-Ni films prepared from a UNi 5 target. (orig.)

  4. Ion exchange of alkaline metals on the thin-layer zinc ferrocyanide

    International Nuclear Information System (INIS)

    Betenekov, N.D.; Buklanov, G.V.; Ipatova, E.G.; Korotkin, Yu.S.

    1991-01-01

    Basic regularities of interphase distribution in the system of thin-layer sorbent on the basis of mixed zinc ferrocyanide (FZ)-alkaline metal solution (Na, K, Rb, Cs, Fr) in the column chromatography made are studied. It is established that interphase distribution of microgram amounts of alkaline metals in the systems thin-layer FZ-NH 4 NO 3 electrolyte solutions is of ion-exchange character and subjected to of law effective mass. It is shown that FZ thin-layer material is applicable for effective chromatographic separation of alkaline metal trace amounts. An approach to the choice of a conditions of separate elution of Na, K, Rb, Cs, Fr in the column chromatography mode

  5. A simple and rapid method for the determination of taxol produced by fungal endophytes from medicinal plants using high performance thin layer chromatography%高效薄层色谱法快速测定由药用植物内生真菌产生的紫杉醇

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Taxol is an important anticancer drug used widely in the clinical field. In this study, some endophytic fungi were isolated from selected medicinal plants, and were screened for their potential in the production of taxol, using a rapid separation technique of high performance thin layer chromatography ( HPTLC ). Of the 20 screened fungi, only 13 fungal species produced taxol in the artificial culture medium.The results of HPTLC showed that the 13 fungal species had identical ultraviolet (UV) characteristics, positive reactivity with a spray reagent, yielding a blue spot, which turned to dark gray after 24 hours, and had Rf values identical to that of the authentic taxol. The amount of taxol was also quantified by comparing the peak area and the peak height of the fungal samples with those of authentic taxol.

  6. Development and validation of a simple high performance thin layer chromatography method combined with direct 1,1-diphenyl-2-picrylhydrazyl assay to quantify free radical scavenging activity in wine.

    Science.gov (United States)

    Agatonovic-Kustrin, Snezana; Morton, David W; Yusof, Ahmad P

    2016-04-15

    The aim of this study was to: (a) develop a simple, high performance thin layer chromatographic (HPTLC) method combined with direct 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay to rapidly assess and compare free radical scavenging activity or anti-oxidant activity for major classes of polyphenolics present in wines; and (b) to investigate relationship between free radical scavenging activity to the total polyphenolic content (TPC) and total antioxidant capacity (TAC) in the wine samples. The most potent free radical scavengers that we tested for in the wine samples were found to be resveratrol (polyphenolic non-flavonoid) and rutin (flavonoid), while polyphenolic acids (caffeic acid and gallic acid) although present in all wine samples were found to be less potent free radical scavengers. Therefore, the total antioxidant capacity was mostly affected by the presence of resveratrol and rutin, while total polyphenolic content was mostly influenced by the presence of the less potent free radical scavengers gallic and caffeic acids. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Estimation of boswellic acids from market formulations of Boswellia serrata extract and 11-keto beta-boswellic acid in human plasma by high-performance thin-layer chromatography.

    Science.gov (United States)

    Shah, Shailesh A; Rathod, Ishwarsinh S; Suhagia, Bhanubhai N; Patel, Dharmesh A; Parmar, Vijay K; Shah, Bharat K; Vaishnavi, Vikas M

    2007-04-01

    A rapid and sensitive high-performance thin-layer chromatographic (HPTLC) method was developed and validated for the quantitative estimation of boswellic acids in formulation containing Boswellia serrata extract (BSE) and 11-keto beta-boswellic acid in human plasma. Simple extraction method was used for isolation of boswellic acid from formulation sample and acidified plasma sample. The isolated samples were chromatographed on silica gel 60F(254)-TLC plates, developed using ternary-solvent system (hexane-chloroform-methanol, 5:5:0.5, v/v) and scanned at 260 nm. The linearity range for 11-KBA spiked in 1 ml of plasma was 29.15-145.75 ng with average recovery of 91.66%. The limit of detection and limit of quantification for 11-KBA in human plasma were found to be 8.75 ng/ml and 29.15 ng/ml. The developed method was successfully applied for the assay of market formulations containing BSE and to determine plasma level of 11-keto beta-boswellic acid in a clinical pilot study.

  8. Preparative separation of capsaicin and dihydrocapsaicin from Capsicum frutescens by high-speed counter-current chromatography.

    Science.gov (United States)

    Peng, Aihua; Ye, Haoyu; Li, Xia; Chen, Lijuan

    2009-09-01

    Capsaicin and dihydrocapsaicin are two main bioactive components of Capsicum frutescens and are widely used as food additives and drugs in China and India. Due to their similarity in structures, isolation of capsaicin and dihydrocapsaicin with traditional methods such as silica gel column chromatography, normal-phase thin-layer chromatography (TLC) becomes difficult. This study involves separating capsaicin and dihydrocapsaicin with sufficient purity and recovery using high-speed counter-current chromatography (HSCCC) with a solvent system composed of n-hexane-ethyl acetate-methanol-water-acetic acid (20:20:20:20:2, v/v/v/v/v). Separation parameters such as sample volume, and sample concentration were first optimized on analytical HSCCC, and then scaled up to preparative HSCCC. 0.65 g capsaicin and 0.28 g dihydrocapsaicin were obtained from 1.2 g crude extract and their purities were 98.5 and 97.8%, respectively. The recoveries of the two compounds were 86.3 and 85.4%, respectively. The purity of the isolated compounds was analyzed by high-performance liquid chromatography (HPLC) and their structures were identified by (1)H nuclear magnetic resonance (NMR) and (13)C NMR analysis.

  9. Thin layer activation: measuring wear and corrosion

    International Nuclear Information System (INIS)

    Delvigne, T.; Leyman, D.; Oxorn, K.

    1995-01-01

    The technique known as thin layer activation (TLA) is explained and assessed in this article. Widely used, in for example the automotive industry, TLA allows on-line monitoring of the loss of matter from a critical surface, by wear erosion and corrosion. The technique offers extremely high sensitivity thus leading to reduced test times. On-line wear phenomena can be assessed during operation of a mechanical process, even through thick engine walls. (UK)

  10. Use of the water-soluble fluor sodium salicylate for fluorographic detection of tritium in thin-layer chromatograms and nitrocellulose blots

    International Nuclear Information System (INIS)

    Lucher, L.A.; Lego, T.

    1989-01-01

    We have determined that sodium salicylate, a water-soluble fluor which we use routinely for fluorography with polyacrylamide gels, is also useful for fluorography with thin-layer media. Detection of 3 H-labeled material applied to thin-layer chromatography plates, or nitrocellulose membranes, can be enhanced up to 150-fold after treatment with an aqueous solution of 2 M sodium salicylate, while detection of 35 S-labeled material is enhanced only about 2-fold. We demonstrate the utility of sodium salicylate fluorography in detecting 3H-labeled palmitic acid following thin-layer chromatography and 3 H-labeled proteins following blotting to nitrocellulose

  11. Bearing Capacity of Footings on Thin Layer of Sand on Soft Cohesive Soil

    DEFF Research Database (Denmark)

    Philipsen, J.; Sørensen, Carsten S.

    2004-01-01

    This paper contains the results of some numerical calculations performed with the aim to determine the bearing capacities of footings placed on a thin layer of sand underlain by soft cohesive soil. During the last 30-35 years different analytical and empirical calculation methods for this situation...... prepared model tests made in laboratories....

  12. High-performance thin-layer chromatography linked with (bio)assays and mass spectrometry - a suited method for discovery and quantification of bioactive components? Exemplarily shown for turmeric and milk thistle extracts.

    Science.gov (United States)

    Taha, Mahmoud N; Krawinkel, Michael B; Morlock, Gertrud E

    2015-05-15

    Extraction parameters, chemical fingerprint, and the single compounds' activity levels were considered for the selection of active botanicals. For an initial survey, the total bioactivity (i.e., total reducing capacity, total flavonoids contents and free radical scavenging capacity) of 21 aqueous and 21 ethanolic plant extracts was investigated. Ethanolic extracts showed a higher yield and were further analyzed by HPTLC in detail to obtain fingerprints of single flavonoids and further bioactive components. Exemplarily shown for turmeric (Curcuma longa) and milk thistle (Silybum marianum), effect-directed analysis (EDA) was performed using three selected (bio)assays, the Aliivibrio fischeri bioassay, the Bacillus subtilis bioassay and the 2,2-diphenyl-1-picrylhydrazyl (DPPH*) assay. As a proof of principle, the bioactive components found in the extracts were confirmed by HPTLC-MS. Bioassays in combination with planar chromatography directly linked to the known, single effective compounds like curcumin and silibinin. However, also some unknown bioactive components were discovered and exemplarily characterized, which demonstrated the strength of this kind of EDA. HPTLC-UV/Vis/FLD-EDA-MS could become a useful tool for selection of active botanicals and for the activity profiling of the active ingredients therein. The flexibility in effect-directed detections allows a comprehensive survey of effective ingredients in samples. This streamlined methodology comprised a non-targeted, effect-directed screening first, followed by a highly targeted characterization of the discovered bioactive compounds. HPTLC-EDA-MS can also be recommended for bioactivity profiling of food on the food intake side, as not only effective phytochemicals, but also unknown bioactive degradation products during food processing or contamination products or residues or metabolites can be detected. Thus, an efficient survey on potential food intake effects on wellness could be obtained. Having performed

  13. Thin layer fibres are a knotty problem

    International Nuclear Information System (INIS)

    Anon.

    1996-01-01

    Concern that emergency core cooling system (ECCS) strainers can be blocked by insulation debris has been generated by an incident at the Swedish Barsebaeck-2 BWR in 1992 and two subsequent incidents at the Perry and Limerick BWR plants in the USA. Recent studies are reported which show that blockage of the small, passive suction type strainers common to these and many other BWRs can occur when only very small quantities of fibrous material present in the suppression pool combine with particulates such as corrosion products to form thin layers on the strainer surface. Layers only a few millimetres thick lead to extremely high head losses on the strainer surface and can cause cavitation in the ECCS pumps. It is concluded that the most practical reliable and cost effective solution is to replace the small strainers with larger ones. (UK)

  14. Preparative supercritical fluid chromatography: A powerful tool for chiral separations.

    Science.gov (United States)

    Speybrouck, David; Lipka, Emmanuelle

    2016-10-07

    In 2012, the 4 biggest pharmaceutical blockbusters were pure enantiomers and separating racemic mixtures is now frequently a key step in the development of a new drug. For a long time, preparative liquid chromatography was the technique of choice for the separation of chiral compounds either during the drug discovery process to get up to a hundred grams of a pure enantiomer or during the clinical trial phases needing kilograms of material. However the advent of supercritical Fluid Chromatography (SFC) in the 1990s has changed things. Indeed, the use of carbon dioxide as the mobile phase in SFC offers many advantages including high flow rate, short equilibration time as well as low solvent consumption. Despite some initial teething troubles, SFC is becoming the primary method for preparative chiral chromatography. This article will cover recent developments in preparative SFC for the separation of enantiomers, reviewing several aspects such as instrumentation, chiral stationary phases, mobile phases or purely preparative considerations including overloading, productivity or large scale chromatography. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Critical Transitions in Thin Layer Turbulence

    Science.gov (United States)

    Benavides, Santiago; Alexakis, Alexandros

    2017-11-01

    We investigate a model of thin layer turbulence that follows the evolution of the two-dimensional motions u2 D (x , y) along the horizontal directions (x , y) coupled to a single Fourier mode along the vertical direction (z) of the form uq (x , y , z) = [vx (x , y) sin (qz) ,vy (x , y) sin (qz) ,vz (x , y) cos (qz) ] , reducing thus the system to two coupled, two-dimensional equations. Its reduced dimensionality allows a thorough investigation of the transition from a forward to an inverse cascade of energy as the thickness of the layer H = π / q is varied.Starting from a thick layer and reducing its thickness it is shown that two critical heights are met (i) one for which the forward unidirectional cascade (similar to three-dimensional turbulence) transitions to a bidirectional cascade transferring energy to both small and large scales and (ii) one for which the bidirectional cascade transitions to a unidirectional inverse cascade when the layer becomes very thin (similar to two-dimensional turbulence). The two critical heights are shown to have different properties close to criticality that we are able to analyze with numerical simulations for a wide range of Reynolds numbers and aspect ratios. This work was Granted access to the HPC resources of MesoPSL financed by the Region Ile de France and the project Equip@Meso (reference ANR-10-EQPX-29-01).

  16. Comparison of thin layer chromatography (TLC) and gas ...

    African Journals Online (AJOL)

    The fate of propoxur in a cocoa ecosystem has been studied using TLC and GC. Residues of propoxur as determined by both TLC and GC were not significantly different. TLC analysis of propoxur residues in soil, cocoa leaves and pods may not need any rigorous clean up since residues measured from cleaned and ...

  17. Phytochemical screening and thin layer chromatography of the ...

    African Journals Online (AJOL)

    Phytochemical constituents of the leaves of Khaya senegalensis (dry zone mahogany) were determined in petroleum ether, chloroform, acetone and ethanol extracts. The screening revealed the presence of flavonoids, carbohydrates, glycosides, saponins, tannins, alkaloids and anthraquinones. Saponins and cardiac ...

  18. PRELIMINARY PHYTOCHEMICAL INVESTIGATION AND THIN LAYER CHROMATOGRAPHY OF RHEUM EMODI

    OpenAIRE

    Mir Ashfaq Ahmad; K. W. Shah; Showkat Ahmad Wani

    2012-01-01

    Preliminary phytochemical investigation of aqueous and methanolic rhizome extracts of Rheum emodi followed by their TLC profiling were carried out. Phytochemical analysis reveals the presence of diverse groups of phytoconstituents in two different extracts (aqueous and methanolic rhizome extracts). Chemical constituents also show different Rf values in two different solvent systems.

  19. Development of High Performance Thin Layer Chromatography for ...

    African Journals Online (AJOL)

    are likely to be found on the market, especially in developing countries. ... was a deuterium lamp emitting a continuous UV spectrum in the range 200– ... disoproxil fumarate. Table 1. Summary of response function of lamivudine and tenofovir ...

  20. High-performance thin-layer chromatography (HPTLC)

    National Research Council Canada - National Science Library

    Srivastava, ManMohan

    2011-01-01

    ... on HPTLC fundamentals: principle, theory, understanding; instrumentation: implementation, optimization, validation, automation and qualitative and quantitative analysis; applications: phytochemical analysis, biomedical analysis, herbal drug quantification, analytical analysis, finger print analysis and potential for hyphenation: HPTLC future to combinat...

  1. Temperature effect with molecular rotors in thin-layer chromatography

    OpenAIRE

    Polanski, Jarosiaw; Sajewicz, Mieczysiaw; Knas, Magdalena; Zywocinski, Andrzej; Weloe, Marcel; Kowalska, Teresa

    2013-01-01

    В серии предыдущих работ охарактеризованы вариации траекторий миграции хиральных ана-литов в тонкослойной хроматографии (ТСХ). Этот эффект, известный под названием «поперечное смещение», был предположительно объяснён действием сил Магнуса на границах раздела фаз «твёрдый сорбент — элюент» и «элюент—воздух» в ТСХ. Отклонения реальных траекторий перемещения хиральных аналитов от ожидаемых прямолинейных демонстрирует новые возможности ТСХ, а именно возможность детектирования так называемых молек...

  2. Robotic thin layer chromatography instrument for synthetic chemistry

    International Nuclear Information System (INIS)

    Corkan, L.A.; Lindsey, J.S.

    1990-01-01

    One of our long-term goals is to develop robotic workstations for automated synthetic chemistry. Toward that goal we have constructed a 2nd generation instrument for performing TLC analysis. TLC has important advantages (over HPLC and GC) in analysis of crude reaction samples and parallel sample development. The TLC instrument consist of four dedicated stations for (1) plate dispensing, (2) sample application, (3) plate development, and (4) plate densitometry. A robot is used to move plates among stations. The combination of fixed automation and robotics gives high sample throughout (up to 10 samples per hour). A second robot performs reaction chemistry and feeds samples to the TLC instrument, thus enabling TLC analysis at the same time as synthetic reactions proceed on the workstation

  3. Csaba Horváth and preparative liquid chromatography.

    Science.gov (United States)

    Guiochon, Georges

    2005-06-24

    Few chromatographers have been interested in furthering preparative liquid chromatography. The pioneers, Tswett, Kuhn and Lederer, A.J.P. Martin, Tiselius, isolated fractions but as an intermediate step in the analysis of their samples. The progress in electronics and sensors, and in their miniaturization has lead to the paradoxical situation that the analysts never see the transient pure fractions that their detector quantitates. Yet, over the last 25 years, preparative liquid chromatography has become an important industrial process for the separation, the extraction, and/or the purification of many pharmaceuticals or pharmaceutical intermediates, including pure enantiomers, purified peptides and proteins, compounds that are manufactured at the relatively large industrial scale of a few kilograms to several hundred tons per year. This development that has strongly affected the modem pharmaceutical industry is mainly due to the pioneering work of Csaba Horváth. His work in preparative HPLC was critical at both the practical and the theoretical levels. He was the first scientist in modem times to pay serious attention to the relationships between the curvature of the equilibrium isotherms, the competitive nature of nonlinear isotherms, and the chromatographic band profiles of complex mixtures. The thermodynamics of multi-component phase equilibria and mass transfer kinetics in chromatography attracted his interest and were the focus of ground-breaking contributions. He investigated displacement chromatography, an old method invented by Tiselius that Csaba was first to implement in HPLC. This choice was explained by the essential characteristic of displacement chromatography, in that it delivers fractions that can be far more concentrated than the feed. Remarkably, once the basics of nonlinear chromatography had been mastered in his group, most of the applications that were studied by his coworkers dealt with peptides of various sizes and with proteins. Thus, all

  4. Thin layer joining by gas adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Taga, Yasunori, E-mail: y-taga@isc.chubu.ac.jp; Fukumura, Toshio

    2014-10-01

    Highlights: • We report thin layer molecular joining between glass and COP by gas adsorption. Thickness of joining layer is 1–2 nm and joining process was carried out at low temperature at about 100 °C. • Adhesion strength measured by 180 degree peel test revealed to be 1–10 N/25 mm and the joined stack showed high durability for practical use. - Abstract: Attempt has been made to join borosilicate glass and cycloolefin (COP) polymer film by using gas adsorption method. After corona plasma treat, COP was exposed to (3-glycidoxypropyl) trimethoxysilane (GPS) and glass to (3-aminopropyl) triethoxysilane (APS) both in air atmosphere, resulting in co-adsorption of water vapor in the atmosphere and organosilane gases. Surface characterization of plasma treated and gas adsorbed surfaces was carried out by X-ray photoelectron spectroscopy (XPS) using Mg Kα X-ray source. Joining was carried out by a roll laminator after contact of both surfaces at room temperature, followed by annealing at 130 °C for 10 min. Adhesion strength was evaluated by 180 degree peel test based on ASTM D-903 and durability was examined under the conditions of 60 °C and 95% RH. It was found that after plasma treatment, complex functional groups such as C-H, C-O, C=O, O-C=O and CO{sub 3} were found on COP and O-H on glass. Thickness of GPS gas adsorption layer on COP was evaluated by the XPS to be at least 1.1 nm by taking inelastic mean free path of Si{sub 2p} photoelectron into consideration. Joining force was found to be more than 5 N/25 mm corresponding to almost equal to COP bulk tensile strength. In addition, durability of this adhesion strength remained unchanged over 2000 h even after exposure to the durability test conditions of 60 °C and 95% RH. The results can be explained in terms of formation of H-H hydrogen bonding and Si-O covalent bonding via silanols will be made at the interface as a result of lamination and annealing processes. In conclusion, ultrathin joining method

  5. Study of wear in piston ring of the vehicle engine using thin layer activation technique

    International Nuclear Information System (INIS)

    Khan, I.H.; Farooq, M.; Ghiyas-ud-Din; Gul, S.; Qureshi, R.M.; Jin Joon Ha; Wallace, G.

    2004-01-01

    Thin Layer Activation (TLA) technique was used to investigate piston ring wear of a six cylinders vehicle engine at various engine speeds and load conditions. The activated ring was installed in cylinder no.5 of the engine at middle position (compression ring). Monitoring was carried out on-line (extremely on the engine block) using 'Thin Layer Difference Method'. The calibration curve of the activity profile was prepared with the help of activation parameters determined at the time of ring activation in particle accelerator. The results show that the piston ring wear varies from 0.309 micron/hour to 0.404 micron/hour at given engine speed and load conditions. (author)

  6. Defect free single crystal thin layer

    KAUST Repository

    Elafandy, Rami Tarek Mahmoud

    2016-01-28

    A gallium nitride film can be a dislocation free single crystal, which can be prepared by irradiating a surface of a substrate and contacting the surface with an etching solution that can selectively etch at dislocations.

  7. Defect free single crystal thin layer

    KAUST Repository

    Elafandy, Rami Tarek Mahmoud; Ooi, Boon S.

    2016-01-01

    A gallium nitride film can be a dislocation free single crystal, which can be prepared by irradiating a surface of a substrate and contacting the surface with an etching solution that can selectively etch at dislocations.

  8. Preparation and evaluation of 99mTc-cefuroxime, a potential infection specific imaging agent: A reliable thin layer chromatographic system to delineate impurities from the 99mTc-antibiotic

    International Nuclear Information System (INIS)

    Chattopadhyay, Sankha; Ghosh, Mayuri; Sett, Sucharita; Das, Malay Kanti; Chandra, Susmita; De, Kakali; Mishra, Mridula; Sinha, Samarendu; Ranjan Sarkar, Bharat; Ganguly, Shantanu

    2012-01-01

    Technetium-99m labelled cefuroxime, a second-generation cephalosporin antibiotic and potential bacteria specific infection imaging agent was evaluated. A good radiochemical purity (95%) of the labelled product was obtained after filtering the reaction mixture through a 0.22 μm filter. Scintigraphy study of the purified product showed uptake in infectious lesions 45 min after injection and abscess-to-muscle ratios were found to be 1.80, 1.85 and 1.88 at 45 min, 1.5 hr and 3 hr, respectively. A versatile and reliable chromatographic technique to assess the radiochemical purity of 99m Tc-cefuroxime has also been described. - Highlights: ► Preparation of 99m Tc-cefuroxime in presence of Sn-tartrate as reducing agent. ► Physiochemical and biological evaluation of 99m Tc-cefuroxime. ► A versatile and reliable chromatographic technique to assess the radiochemical purity of 99m Tc-cefuroxime.

  9. Copper diffusion in TaN-based thin layers

    Energy Technology Data Exchange (ETDEWEB)

    Nazon, J. [Universite Montpellier II, Institut Charles Gerhardt, UMR 5253 CNRS-UM2-ENSCM-UM1, cc 1504, 34095 Montpellier Cedex 5 (France); Fraisse, B. [Laboratoire Structure, Proprietes et Modelisation des Solides (UMR 8580), Ecole Centrale de Paris, Grande Voie des Vignes, 92295 Chatenay-Malabry Cedex (France); Sarradin, J. [Universite Montpellier II, Institut Charles Gerhardt, UMR 5253 CNRS-UM2-ENSCM-UM1, cc 1504, 34095 Montpellier Cedex 5 (France); Fries, S.G. [SGF Scientific Consultancy, Arndt str.9, D-52064 Aachen (Germany); Tedenac, J.C. [Universite Montpellier II, Institut Charles Gerhardt, UMR 5253 CNRS-UM2-ENSCM-UM1, cc 1504, 34095 Montpellier Cedex 5 (France); Frety, N. [Universite Montpellier II, Institut Charles Gerhardt, UMR 5253 CNRS-UM2-ENSCM-UM1, cc 1504, 34095 Montpellier Cedex 5 (France)], E-mail: Nicole.Frety@univ-montp2.fr

    2008-07-15

    The diffusion of Cu through TaN-based thin layers into a Si substrate has been studied. The barrier efficiency of TaN/Ta/TaN multilayers of 150 nm in thickness has been investigated and is compared with that of TaN single layers. Thermal stabilities of these TaN-based thin layers against Cu diffusion were determined from in situ X-ray diffraction experiments, conducted in the temperature range of 773-973 K. The TaN/Ta/TaN barrier appeared to be more efficient in preventing Cu diffusion than the TaN single layer.

  10. Non thermal preparation of photoactive titanium (IV) oxide thin layers

    Czech Academy of Sciences Publication Activity Database

    Klusoň, P.; Lusková, H.; Cajthaml, Tomáš; Šolcová, Olga

    2006-01-01

    Roč. 495, - (2006), s. 18-23 ISSN 0040-6090 R&D Projects: GA ČR GA104/04/0963; GA ČR GD203/03/H140; GA MPO FT-TA/023 Institutional research plan: CEZ:AV0Z50200510; CEZ:AV0Z40720504 Keywords : titanium dioxide * nanostructures * photocatalysis Subject RIV: EE - Microbiology, Virology Impact factor: 1.666, year: 2006

  11. Outdoor open thin-layer microalgal photobioreactor: potential productivity

    Czech Academy of Sciences Publication Activity Database

    Doucha, Jiří; Lívanský, Karel

    2009-01-01

    Roč. 21, č. 1 (2009), s. 111-117 ISSN 0921-8971 Institutional research plan: CEZ:AV0Z50200510 Keywords : productivity * photobioreactor * thin layer Subject RIV: EE - Microbiology, Virology Impact factor: 1.018, year: 2009

  12. Modeling of thin layer drying of tarragon (Artemisia dracunculus L.)

    NARCIS (Netherlands)

    ArabHosseini, A.; Huisman, W.; Boxtel, van A.J.B.; Mueller, J.

    2009-01-01

    The drying behavior of tarragon leaves as well as chopped plants were evaluated at air temperatures ranging from 40 to 90 °C, at various air relative humidities and a constant air velocity of 0.6 m/s. The experimental data was fitted to a number of thin layer drying equations. The equations were

  13. (AJST) THIN- LAYER DRYING OF DICED CASSAVA ROOTS

    African Journals Online (AJOL)

    opiyo

    effect of drying temperature on thin-layer drying was high, followed by initial moisture .... The moisture content was converted to moisture ratio (MR) using the non-exponential part .... The Potential of Cassava As a Cash. Crop For Small Holder ...

  14. Thin Layer Drying Kinetics of Pineapple: Effect of Blanching ...

    African Journals Online (AJOL)

    Four thin-layer drying models were fitted to the experimental drying data. The .... MATLAB software package (version 6.5). The correlation ... to evaluate the goodness of fit of the simulation ... during the oven-drying process of pineapple slices.

  15. Thin layer activation techniques in research and industry

    International Nuclear Information System (INIS)

    Conlon, T.W.

    1993-01-01

    The following key application of thin layer activation technique (TLA) are discussed: ion-erosion in fusion tokamaks, bio-engineering technology, automobile industry. Future developments of the techniques, such as fission fragment TLA, multi-layer TLA and recoil implantation are discussed as well. 7 refs, 6 figs, 1 tab

  16. Auger electron spectroscopy study on interaction between aluminum thin layers and uranium substrate

    International Nuclear Information System (INIS)

    Zhou Wei; Liu Kezhao; Yang Jiangrong; Xiao Hong; Jiang Chunli; Lu Lei

    2005-01-01

    Aluminum thin layers on uranium were prepared by sputter deposition at room temperature in ultra high vacuum analysis chamber. Interaction between U and Al, and growth mode were investigated by Auger electron spectroscopy (AES) and electron energy loss spectroscopy (EELS). It is shown that Al thin film growth follows the volmer-weber (VW) mode. At room temperature, Al and U interact with each other, resulting in interdiffusion action and formation of U-Al alloys at U/Al interface. Annealing promotes interaction and interdiffusion between U and Al, and UAl x maybe formed at interface. (authors)

  17. Measurement of the oxygen binding properties of haemocyanin with the aid of a thin-layer optical cell

    Directory of Open Access Journals (Sweden)

    W. J. van Aardt

    1992-07-01

    Full Text Available The merits of the thin-layer method of Dolman and Gill to study the oxygen binding of haemocyanin were experimentally tested with haemocyanin obtained from arthropods and molluscs. The results show that, spectrophotometrically, oxyhaemocyanin from both arthropods and molluscs has a prominent absorption peak between 335 and 345 nm. Haemocyanin is more stable in the thin- layer preparation when compared with haemoglobin. At 35 °C a decrease in the initial absorbance value of less than 2% was found after three hours. For haemoglobin the initial value decreases nearly 10% during the same period. For a high-affinity haemocyanin such as Marisa cornuarietis (P⁵⁰ = 1,07 mmHg the thin-layer method of Dolman and Gill (1978 shows better PO₂ resolution than other methods. The reason for this is that the dilution valve, which is absent in other thin-layer methods, intrinsically measures the resultant PO₂ values at very low tensions more accurately. In this study a step-by-step explanation of the technique is given. The calculations have been explained using real figures and examples. It is hoped that this detailed description will make this technique more readily available for use by respiratory physiologists.

  18. Thin layer chromatographic method for the detection of uric acid: collaborative study.

    Science.gov (United States)

    Thrasher, J J; Abadie, A

    1978-07-01

    A collaborative study has been completed on an improved method for the detection and confirmation of uric acid from bird and insect excreta. The proposed method involves the lithium carbonate solubilization of the suspect excreta material, followed by butanol-methanol-water-acetic acid thin layer chromatography, and trisodium phosphate-phosphotungstic acid color development. The collaborative tests resulted in 100% detection of uric acid standard at the 50 ng level and 75% detection at the 20-25 ng level. No false positives were reported during tests of compounds similar to uric acid. The proposed method has been adopted official first action; the present official final action method, 44.161, will be retained for screening purposes.

  19. The production of ultra-thin layers of ion-exchange resin and metallic silver by electrospraying

    International Nuclear Information System (INIS)

    Wyllie, H.A.

    1988-10-01

    Highly efficient radioactive sources for use in radioisotope metrology have been prepared on ultra-thin layers of electrosprayed ion-exchange resin. The efficiency of these sources can be reduced for the purpose of radioactivity standardisation by coating them with conducting silver layers which are also produced by electrospraying. A description is given of improvements to the electrospraying methods, together with details of the rotating, oscillating source-mount turntable

  20. Intoxicação em cães e gatos: diagnóstico toxicológico empregando cromatografia em camada delgada e cromatografia líquida de alta pressão com detecção ultravioleta em amostras estomacais Intoxication in dogs and cats: toxicological diagnosis using thin layer chromatography and high pressure liquid chromatography with ultraviolet detection in stomach samples

    Directory of Open Access Journals (Sweden)

    Rachel Picada Bulcão

    2010-05-01

    óticos mais envolvidos nessas intoxicações.The pesticides and rodenticides are responsible for several human and animal intoxications. Preliminary data suggest that the illegal use of these compounds to poison small animals is a common practice in the central region of the Rio Grande do Sul state. The Laboratory of Toxicology received samples, of cases in which the main suspected cause of death is poisoning by pesticides or exogenous rodenticides (licit and illicit. The aim of this study was show the survey of small animals poisoned and analyzed by LATOX during the period of 2004 to 2008 identifying the xenobiotics by optimized analytical methods, including screening by thin-layer chromatography (TLC and a possible confirmation by high performance liquid chromatography - ultraviolet detection (HPLC-UV. In this period 68 samples were analyzed from small poisoned animals. The biological samples analyzed were stomach and stomach content and the TLC permitted carbamates, warfarin and stricnine identification. This proved to be an efficient and adequate technique for this purpose, relatively fast, inexpensive and with low matrix interference. The screening by HPLC for N-methyl carbamates was also realized: aldicarb, carbaryl, carbofuran and propoxur. The analysis showed that the main toxic agent found was aldicarb (chumbinho, responsible for 39.7% of poisoning (27 cases, followed by stricnine (6 cases, warfarin (3 cases and sodium monofluoracetate (1 case. Thus, the 'chumbinho' was the main agent involved in dogs and cats poisoning in the central region of the state, during the analyzed period. The analytical methods TLC and HPLC can be used efficiently in laboratorial routine for identification and confirmation of xenobiotics involved in these poisonings.

  1. Mathematical modelling of thin layer drying of pear

    Directory of Open Access Journals (Sweden)

    Lutovska Monika

    2016-01-01

    Full Text Available In this study, a thin - layer drying of pear slices as a function of drying conditions were examined. The experimental data set of thin - layer drying kinetics at five drying air temperatures 30, 40, 50, 60 and 70°C, and three drying air velocities 1, 1.5 and 2 m s-1 were obtained on the experimental setup, designed to imitate industrial convective dryer. Five well known thin - layer drying models from scientific literature were used to approximate the experimental data in terms of moisture ratio. In order to find which model gives the best results, numerical experiments were made. For each model and data set, the statistical performance index, (φ, and chi-squared, (χ2, value were calculated and models were ranked afterwards. The performed statistical analysis shows that the model of Midilli gives the best statistical results. Because the effect of drying air temperature and drying air velocity on the empirical parameters was not included in the base Midilli model, in this study the generalized form of this model was developed. With this model, the drying kinetic data of pear slices can be approximated with high accuracy. The effective moisture diffusivity was determined by using Fick’s second laws. The obtained values of the effective moisture diffusivity, (Deff, during drying ranged between 6.49 x 10-9 and 3.29 x 10-8 m2 s-1, while the values of activation energy (E0 varied between 28.15 to 30.51 kJ mol-1.

  2. Thin-Layer Solutions of the Helmholtz and Related Equations

    KAUST Repository

    Ockendon, J. R.

    2012-01-01

    This paper concerns a certain class of two-dimensional solutions to four generic partial differential equations-the Helmholtz, modified Helmholtz, and convection-diffusion equations, and the heat conduction equation in the frequency domain-and the connections between these equations for this particular class of solutions.S pecifically, we consider thin-layer solutions, valid in narrow regions across which there is rapid variation, in the singularly perturbed limit as the coefficient of the Laplacian tends to zero.F or the wellstudied Helmholtz equation, this is the high-frequency limit and the solutions in question underpin the conventional ray theory/WKB approach in that they provide descriptions valid in some of the regions where these classical techniques fail.E xamples are caustics, shadow boundaries, whispering gallery, and creeping waves and focusing and bouncing ball modes.It transpires that virtually all such thin-layer models reduce to a class of generalized parabolic wave equations, of which the heat conduction equation is a special case. Moreover, in most situations, we will find that the appropriate parabolic wave equation solutions can be derived as limits of exact solutions of the Helmholtz equation.W e also show how reasonably well-understood thin-layer phenomena associated with any one of the four generic equations may translate into less well-known effects associated with the others.In addition, our considerations also shed some light on the relationship between the methods of matched asymptotic, WKB, and multiple-scales expansions. © 2012 Society for Industrial and Applied Mathematics.

  3. Rosenzweig instability in a thin layer of a magnetic fluid

    Science.gov (United States)

    Korovin, V. M.

    2013-12-01

    A simple mathematical model of the initial stage of nonlinear evolution of the Rosenzweig instability in a thin layer of a nonlinearly magnetized viscous ferrofluid coating a horizontal nonmagnetizable plate is constructed on the basis of the system of equations and boundary conditions of ferrofluid dynamics. A dispersion relation is derived and analyzed using the linearized equations of this model. The critical magnetization of the initial layer with a flat free surface, the threshold wavenumber, and the characteristic time of evolution of the most rapidly growing mode are determined. The equation for the neutral stability curve, which is applicable for any physically admissible law of magnetization of a ferrofluid, is derived analytically.

  4. The thin layer technique and its application to electron microscopy

    International Nuclear Information System (INIS)

    Ranc, G.

    1957-10-01

    This work deals with the technique of thin layers obtained by evaporation under vacuum, in the thickness range extending from a few monoatomic layers to several hundred angstroms. The great theoretical and practical interest of these layers has, it is well known, given rise to many investigations from Faraday onwards. Within the necessarily restricted limits of this study, we shall approach the problem more particularly from the point of view of: - their production; - their use in electron microscopy. A critical appraisal is made, in the light of present-day knowledge, based on our personal experience and on an extensive bibliography which we have collected on the subject. (author) [fr

  5. Acquisition of Preparative Gel Permeation Chromatography for Research and Education in Energy Conversion and Nanocomposites

    Science.gov (United States)

    2017-04-19

    AFRL-AFOSR-VA-TR-2017-0090 Acquisition of Preparative Gel Permeation Chromatography for Research and Education in Energy Conversion and...TITLE AND SUBTITLE Acquisition of Preparative Gel Permeation Chromatography for Research and Education in Energy Conversion and Nanocomposites 5a... research with education at all levels across a broad range of materials, and create important opportunities to expose and train undergraduates, women

  6. Thin-layer chromatographic determination of erythromycin and other macrolide antibiotics in livestock products.

    Science.gov (United States)

    Petz, M; Solly, R; Lymburn, M; Clear, M H

    1987-01-01

    A method is described for determination of 4 macrolide antibiotics in livestock products. Erythromycin, tylosin, oleandomycin, and spiramycin were extracted from animal tissues, milk, and egg with acetonitrile at pH 8.5. Cleanup was done by adding sodium chloride and dichloromethane, evaporating the organic layer, and subsequent acid/base partitioning. After the antibiotics were separated by thin-layer chromatography (TLC), they were reacted with xanthydrol and could be detected as purple spots down to 0.02 mg/kg without interference by other commonly used therapeutic drugs (23 were tested). Anisaldehyde-sulfuric acid, cerium sulfate-molybdic acid, phosphomolybdic acid, and Dragendorff's reagent proved to be less sensitive as visualizing agents. For quantitation, TLC plates were scanned at 525 nm. Recoveries were between 71 and 96% for erythromycin and tylosin in liver, muscle, and egg at the 0.1-0.5 mg/kg level and 51% for erythromycin in milk at the 0.02 mg/kg level (coefficient of variation = 10-18%). Bioautography with Bacillus subtilis was used to confirm results, in addition to TLC analysis of derivatized antibiotics and liquid chromatography with electrochemical detection. Various derivatization procedures for erythromycin were investigated for improved ultra-violet or fluorescence detection in liquid chromatography.

  7. Thin layer activation and ultra thin layer activation: two complementary techniques for wear and corrosion studies in various fields

    International Nuclear Information System (INIS)

    Sauvage, T.; Vincent, L.; Blondiaux, G.

    2002-01-01

    Thin layer activation (TLA) is widely used since more than 25 years to study surface wear or corrosion. This well known technique uses most of the time charged particles activation, which gives sensitivity in the range of the micrometer, except when the fluid mode of detection is utilized. In this case application of the method is limited to phenomena where we have transport of radioactive fragments to detection point. The main disadvantage of this procedure is the error due to trapping phenomena between the wear or corrosion point and detection setup. So the ultra thin layer activation (UTLA) has been developed to get nanometric sensitivity without using any fluid for radioactivity transportation, which is the main source of error of the TLA technique. In this paper we shall briefly describe the TLA technique and the most important fields of application. Then we shall emphasise on UTLA with a presentation of the principle of the method and actual running of application. The main problem concerning UTLA is calibration which requires the use of thin films (usually 10 to 100 nanometers) deposited on substrate. This process is time consuming and we shall demonstrate how running software developed in the lab can solve it. We shall finish the presentation by giving some potential application of the technique in various fields. (authors)

  8. The thin layer activation method and its applications in industry

    International Nuclear Information System (INIS)

    1997-01-01

    The thin layer activation (TLA) method is one of the most effective and precise methods for the measurement and monitoring of corrosion (erosion) and wear in industry and is used for on-line remote measurement of wear and corrosion rate of central parts in machines or processing vessels under real operating conditions. This document is a comprehensive manual on TLA method in its applications for monitoring wear and corrosion in industry. It describes the theory and presents case studies on TLA method applications in industry. In addition, in annexes are given tables of nuclear data relating to TLA (decay characteristics, depth distribution of reaction products, activation data for charged-particle nuclear reactions), references from INIS database on TLA and a detailed production of the application of TLA for wear measurement of superhard turning tools

  9. Thin layer modelling of Gelidium sesquipedale solar drying process

    International Nuclear Information System (INIS)

    Ait Mohamed, L.; Ethmane Kane, C.S.; Kouhila, M.; Jamali, A.; Mahrouz, M.; Kechaou, N.

    2008-01-01

    The effect of air temperature and air flow rate on the drying kinetics of Gelidium sesquipedale was investigated in convective solar drying. Drying was conducted at 40, 50 and 60 deg. C. The relative humidity was varied from 50% to 57%, and the drying air flow rate was varied from 0.0277 to 0.0833 m 3 /s. The expression for the drying rate equation is determined empirically from the characteristic drying curve. Thirteen mathematical models of thin layer drying are selected in order to estimate the suitable model for describing the drying curves. The two term model gives the best prediction of the drying curves and satisfactorily describes the drying characteristics of G. sesquipedale with a correlation coefficient R of 0.9999 and chi-square (χ 2 ) of 3.381 x 10 -6

  10. Thin layer modelling of Gelidium sesquipedale solar drying process

    Energy Technology Data Exchange (ETDEWEB)

    Ait Mohamed, L. [Laboratoire d' Energie Solaire et des Plantes Aromatiques et Medicinales, Ecole Normale Superieure, BP 2400, Marrakech (Morocco); Faculte des Sciences Semlalia, BP 2390, Marrakech (Morocco); Ethmane Kane, C.S. [Faculte des Sciences de Tetouan, BP 2121, Tetouan (Morocco); Kouhila, M.; Jamali, A. [Laboratoire d' Energie Solaire et des Plantes Aromatiques et Medicinales, Ecole Normale Superieure, BP 2400, Marrakech (Morocco); Mahrouz, M. [Faculte des Sciences Semlalia, BP 2390, Marrakech (Morocco); Kechaou, N. [Ecole Nationale d' Ingenieurs de Sfax, BPW 3038 (Tunisia)

    2008-05-15

    The effect of air temperature and air flow rate on the drying kinetics of Gelidium sesquipedale was investigated in convective solar drying. Drying was conducted at 40, 50 and 60 C. The relative humidity was varied from 50% to 57%, and the drying air flow rate was varied from 0.0277 to 0.0833 m{sup 3}/s. The expression for the drying rate equation is determined empirically from the characteristic drying curve. Thirteen mathematical models of thin layer drying are selected in order to estimate the suitable model for describing the drying curves. The two term model gives the best prediction of the drying curves and satisfactorily describes the drying characteristics of G. sesquipedale with a correlation coefficient R of 0.9999 and chi-square ({chi}{sup 2}) of 3.381 x 10{sup -6}. (author)

  11. The thin layer activation method and its applications in industry

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-01-01

    The thin layer activation (TLA) method is one of the most effective and precise methods for the measurement and monitoring of corrosion (erosion) and wear in industry and is used for on-line remote measurement of wear and corrosion rate of central parts in machines or processing vessels under real operating conditions. This document is a comprehensive manual on TLA method in its applications for monitoring wear and corrosion in industry. It describes the theory and presents case studies on TLA method applications in industry. In addition, in annexes are given tables of nuclear data relating to TLA (decay characteristics, depth distribution of reaction products, activation data for charged-particle nuclear reactions), references from INIS database on TLA and a detailed production of the application of TLA for wear measurement of superhard turning tools.

  12. Investigation of Processes and Factors Regulating the Generation, Maintenance and Breakdown of Bioluminescent Thin Layers

    National Research Council Canada - National Science Library

    Widder, Edith

    2001-01-01

    .... Katz's submersible holographic camera mounted on the upper work platform. Thin layers were located using real-time sensor feedback from intensified video recordings of stimulated bioluminescence...

  13. Use of a wedge cuvette in thin layer photometry and its application to oximetry

    NARCIS (Netherlands)

    Spaan, J. A.; Garred, L. J.; van de Borne, P.

    1977-01-01

    A wedge cuvette was constructed by fixing 2 glass plates at a known angle with a spacer at one end. This resulted in a thin layer with thickness varying from 0 to 250 micrometer. By measuring the intensity of a beam of light through the thin layer as a function of distance along the wedge (and thus

  14. Review and applicative perspectives of thin layer activation in Romania

    International Nuclear Information System (INIS)

    Racolta, P.M.

    1999-01-01

    The Thin Layer Activation (TLA) is an ion beam based technique. It consists in an accelerated ion bombardment of the surface of interest of a machine part subjected to wear. Wear and some types of corrosion phenomena characterized by a loss of material can be studied by monitoring the resulted changes in radioactivity. In this paper some general considerations on the physical phenomena involved, a short description of the two developed measuring methods, a zoom on the specific steps of the experiments (irradiation, calibration, experimental setups and instrumentation), and some applications will be presented. Although the level of activity used in TLA lies under the limit of the range considered to be safe from the point of view of radiation protection, industry hesitates to use this technique mainly due to psychological reasons with respect to the handling of radioactive material. Recognizing this problem we have decided to offer to industry wear/corrosion measurements using TLA in the form of a 'complete package'. The conception of this procedure will be presented also. (author)

  15. Mathematical Modeling of Thin Layer Microwave Drying of Taro Slices

    Science.gov (United States)

    Kumar, Vivek; Sharma, H. K.; Singh, K.

    2016-03-01

    The present study investigated the drying kinetics of taro slices precooked in different medium viz water (WC), steam (SC) and Lemon Solution (LC) and dried at different microwave power 360, 540 and 720 W. Drying curves of all precooked slices at all microwave powers showed falling rate period along with a very short accelerating period at the beginning of the drying. At all microwave powers, higher drying rate was observed for LC slices as compared to WC and SC slices. To select a suitable drying curve, seven thin-layer drying models were fitted to the experimental data. The data revealed that the Page model was most adequate in describing the microwave drying behavior of taro slices precooked in different medium. The highest effective moisture diffusivity value of 2.11 × 10-8 m2/s was obtained for LC samples while the lowest 0.83 × 10-8 m2/s was obtained for WC taro slices. The activation energy (E a ) of LC taro slices was lower than the E a of WC and SC taro slices.

  16. Mathematical analogies in physics. Thin-layer wave theory

    Directory of Open Access Journals (Sweden)

    José M. Carcione

    2014-03-01

    Full Text Available Field theory applies to elastodynamics, electromagnetism, quantum mechanics, gravitation and other similar fields of physics, where the basic equations describing the phenomenon are based on constitutive relations and balance equations. For instance, in elastodynamics, these are the stress-strain relations and the equations of momentum conservation (Euler-Newton law. In these cases, the same mathematical theory can be used, by establishing appropriate mathematical equivalences (or analogies between material properties and field variables. For instance, the wave equation and the related mathematical developments can be used to describe anelastic and electromagnetic wave propagation, and are extensively used in quantum mechanics. In this work, we obtain the mathematical analogy for the reflection/refraction (transmission problem of a thin layer embedded between dissimilar media, considering the presence of anisotropy and attenuation/viscosity in the viscoelastic case, conductivity in the electromagnetic case and a potential barrier in quantum physics (the tunnel effect. The analogy is mainly illustrated with geophysical examples of propagation of S (shear, P (compressional, TM (transverse-magnetic and TE (transverse-electric waves. The tunnel effect is obtained as a special case of viscoelastic waves at normal incidence.

  17. Statistical-mechanical entropy by the thin-layer method

    International Nuclear Information System (INIS)

    Feng, He; Kim, Sung Won

    2003-01-01

    G. Hooft first studied the statistical-mechanical entropy of a scalar field in a Schwarzschild black hole background by the brick-wall method and hinted that the statistical-mechanical entropy is the statistical origin of the Bekenstein-Hawking entropy of the black hole. However, according to our viewpoint, the statistical-mechanical entropy is only a quantum correction to the Bekenstein-Hawking entropy of the black-hole. The brick-wall method based on thermal equilibrium at a large scale cannot be applied to the cases out of equilibrium such as a nonstationary black hole. The statistical-mechanical entropy of a scalar field in a nonstationary black hole background is calculated by the thin-layer method. The condition of local equilibrium near the horizon of the black hole is used as a working postulate and is maintained for a black hole which evaporates slowly enough and whose mass is far greater than the Planck mass. The statistical-mechanical entropy is also proportional to the area of the black hole horizon. The difference from the stationary black hole is that the result relies on a time-dependent cutoff

  18. Thin layer activation technique applied to the measurement of wear

    Energy Technology Data Exchange (ETDEWEB)

    Humphries, P [UKAEA Research Group, Harwell. Atomic Energy Research Establishment

    1978-01-01

    A thin layer of radioactive atoms is produced in the material by bombardment with charged particles, and as the material is worn away the total activity level is monitored. If the activity to depth relationship is then known the amount of material worn away can be determined. By a selective choice of the charged particle species and energy the depth of the active layer, its natural decay rate, and the energy of the emitted radiation can be pre-determined. The Harwell Tandem Electrostatic Generator has been found very suitable for the work. The total activity level can be made as little or as large as required, but a level around 5 to 10 microcuries is usually found to be adequate, and the active layer usually has a depth of 50 to 300 ..mu..m. The activated area can be from < 1 mm/sup 2/ to 4 cm/sup 2/. Particular reference is made to the production of /sup 56/Co in Fe. Experimental arrangements for the irradiation of components are described. Some practical applications undertaken by Harwell for industry are briefly mentioned, including wear of diesel engine valve seatings and fuel injection equipment, engine testing of lubricants, surface loss of rails and railway wheels, wear of gears, wear of graphite bearing materials, and corrosion and erosion of materials. 4 references.

  19. Application of thin layer activation method to industrial use

    International Nuclear Information System (INIS)

    Yamamoto, Masago; Hatakeyama, Noriko

    1996-01-01

    A thin layer activation method was reviewed for non-destructive, rapid, precise and real-time measurement of wear and corrosion. The review included wear measurement, the principle of the method, actual measurement, application, and laws and regulations. The method is to activate the material surface alone by accelerated ions like p, d and He ions produced by cyclotron, Van de Graaf apparatus or other accelerators and to utilize the yielded radioisotopes as a tracer, is widely used in the tribology field, and is more useful than the previous method with the reactor since it activated the whole material. Application of the method was reportedly resulted in saving the 80% cost and 90% time in the wear measurement of automobile parts such as engine and transmission. Actually, the activated material was combined into the part to be run and the radioactivity was to be measured externally or in the worn particles suitably collected. The activation thickness was generally in the range of 10-200 μm and the resultant radioactivity, 0.2-2 MBq. In most cases in Japan, the method would be under the law concerning prevention from radiation hazards due to radioisotopes, etc. (K.H.)

  20. Column chromatography as a useful step in purification of diatom pigments.

    Science.gov (United States)

    Tokarek, Wiktor; Listwan, Stanisław; Pagacz, Joanna; Leśniak, Piotr; Latowski, Dariusz

    2016-01-01

    Fucoxanthin, diadinoxanthin and diatoxanthin are carotenoids found in brown algae and most other heterokonts. These pigments are involved in photosynthetic and photoprotective reactions, and they have many potential health benefits. They can be extracted from diatom Phaeodactylum tricornutum by sonication, extraction with chloroform : methanol and preparative thin layer chromatography. We assessed the utility of an additional column chromatography step in purification of these pigments. This novel addition to the isolation protocol increased the purity of fucoxanthin and allowed for concentration of diadinoxanthin and diatoxanthin before HPLC separation. The enhanced protocol is useful for obtaining high purity pigments for biochemical studies.

  1. Quality control of residual solvents in [18F]FDG preparations by gas chromatography

    International Nuclear Information System (INIS)

    Lee, Hak Jeong; Jeong, Jae Min; Lee, Yun Sang; Kim, Hyung Woo; Chang, Young Soo; Lee, Dong Soo; Chung, June Key; Lee, Myung Chul

    2007-01-01

    Analysis of volatile organic solvents in 2-deoxy-2[ 18 F] fluoro-D-glucose ([ 18 F]FDG) preparations was performed by gas chromatography (GC), in accordance with USP. Analyses were carried out on a Hewlett-Packard 6890 gas chromatography equipped with an FID. We determined the amounts of ethanol and acetonitrile on every batch of our routine [ 18 F]FDG preparations, ranging between 5000 ppm and 100 ppm. In our routine preparation of [ 18 F]FDG, the amount of acetonitrile and ethanol in the final product were well below the maximum allowable limit described in the USP. Our [ 18 F]FDG preparations were in accordance with the suggested USP maximum allowable levels of the quality control analysis of volatile organic compounds

  2. Extraction and Purification of Glucoraphanin by Preparative High-Performance Liquid Chromatography (HPLC)

    Science.gov (United States)

    Lee, Iris; Boyce, Mary C.

    2011-01-01

    A student activity that focuses on the isolation of glucoraphanin from broccoli using preparative high-performance liquid chromatography (HPLC) is presented here. Glucoraphanin is a glucosinolate, whose byproducts are known to possess anticancer properties. It is present naturally at high levels in broccoli and other "Brassica" vegetables. This…

  3. Purification of flavonoids from licorice using an off-line preparative two-dimensional normal-phase liquid chromatography/reversed-phase liquid chromatography method.

    Science.gov (United States)

    Fan, Yunpeng; Fu, Yanhui; Fu, Qing; Cai, Jianfeng; Xin, Huaxia; Dai, Mei; Jin, Yu

    2016-07-01

    An orthogonal (71.9%) off-line preparative two-dimensional normal-phase liquid chromatography/reversed-phase liquid chromatography method coupled with effective sample pretreatment was developed for separation and purification of flavonoids from licorice. Most of the nonflavonoids were firstly removed using a self-made Click TE-Cys (60 μm) solid-phase extraction. In the first dimension, an industrial grade preparative chromatography was employed to purify the crude flavonoids. Click TE-Cys (10 μm) was selected as the stationary phase that provided an excellent separation with high reproducibility. Ethyl acetate/ethanol was selected as the mobile phase owing to their excellent solubility for flavonoids. Flavonoids co-eluted in the first dimension were selected for further purification using reversed-phase liquid chromatography. Multiple compounds could be isolated from one normal-phase fraction and some compounds with bad resolution in one-dimensional liquid chromatography could be prepared in this two-dimensional system owing to the orthogonal separation. Moreover, this two-dimensional liquid chromatography method was beneficial for the preparation of relatively trace flavonoid compounds, which were enriched in the first dimension and further purified in the second dimension. Totally, 24 flavonoid compounds with high purity were obtained. The results demonstrated that the off-line two-dimensional liquid chromatography method was effective for the preparative separation and purification of flavonoids from licorice. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Thin layer chromatographic analysis of food colorants from three morphotypes of annatto (Bixa orellana L.

    Directory of Open Access Journals (Sweden)

    Hari Pada Seal

    2012-06-01

    Full Text Available This article describes a simple solvent extraction method for the extraction of colorants from the three morphotypes such as, (Morphotype-1 (M1, Morphotype-2 (M2, and Morphotype-3 (M3 of Annatto (Bixa orellana L. seeds, and their separation, vivid, and qualitative demonstration by thin-layer chromatography. Several solvent systems (hexane, chloroform, acetone, ethanol, and a mixed-solvent having composition of CHCl3/C2H5OH/CH3COOH (80:2:1 were applied for extraction of colored components. It was observed that a large portion of colorants was extracted by chloroform. Its effluent was deep brick red in color and transparent. Furthermore, various carrier solvent systems (Benzene-Ethyl acetate were used to separate the components from the extracts. Carrier solvent system with the ratio of 7:3 was found as superior solvent for chloroform extracts. Three colored-spots were observed for all morphotypes. Among them, the first one was yellow colored having very low polarity and the second and third spots were both redbrick colored having medium and higher polarity respectively. In addition, for M1 no colorless-spot was observed in low and medium polar systems, revealing that the amount of wax and gum were minimum in the extract and superior morphotype among the three.

  5. Comparison of different thin layer detection techniques to determine the radiochemical purity of radiopharmaceuticals

    International Nuclear Information System (INIS)

    Hammermaier, A.; Reich, E.; Boegl, W.

    1985-01-01

    Ten radiopharmaceuticals frequently used in clinical treatment were examined as to their radiochemical purity by paper and thin layer chromatography or electrophoresis, respectively. It is known that radiochemical impurities may result in an unnecessary exposure of the patients to be examined. Other than determining the radiochemical purity of several radiopharmaceuticals, a comparison of the different measuring methods of distributing activity on radiochromatograms or electropherograms is intended by this study. For this, the activity distribution in the developed radiochromatograms was assessed by four different measuring methods (TLC-linear analyzer, TLC-scanner with NaI(Tl) detector, TLC-scanner with gas flow counter and NaI(Tl) well-typ counter). As shown by the above analysis, only the TLC-linear analyzer and the NaI(Tl) well-typ counter (measurement of chromatograms or electropherograms cut into strips) are generally suitable methods for determining the radiochemical purity of radiochemicals, the TLC-scanner with gas flow counter is usable in most cases, while TLC-scanner with NaI(Tl) detector is yielding unsatisfactory results. (orig.) [de

  6. Schinus terebinthifolius countercurrent chromatography (Part III): Method transfer from small countercurrent chromatography column to preparative centrifugal partition chromatography ones as a part of method development.

    Science.gov (United States)

    das Neves Costa, Fernanda; Hubert, Jane; Borie, Nicolas; Kotland, Alexis; Hewitson, Peter; Ignatova, Svetlana; Renault, Jean-Hugues

    2017-03-03

    Countercurrent chromatography (CCC) and centrifugal partition chromatography (CPC) are support free liquid-liquid chromatography techniques sharing the same basic principles and features. Method transfer has previously been demonstrated for both techniques but never from one to another. This study aimed to show such a feasibility using fractionation of Schinus terebinthifolius berries dichloromethane extract as a case study. Heptane - ethyl acetate - methanol -water (6:1:6:1, v/v/v/v) was used as solvent system with masticadienonic and 3β-masticadienolic acids as target compounds. The optimized separation methodology previously described in Part I and II, was scaled up from an analytical hydrodynamic CCC column (17.4mL) to preparative hydrostatic CPC instruments (250mL and 303mL) as a part of method development. Flow-rate and sample loading were further optimized on CPC. Mobile phase linear velocity is suggested as a transfer invariant parameter if the CPC column contains sufficient number of partition cells. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Two-dimensional preparative liquid chromatography system for preparative separation of minor amount components from complicated natural products

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Ying-Kun, E-mail: qyk@xmu.edu.cn; Chen, Fang-Fang; Zhang, Ling-Ling; Yan, Xia; Chen, Lin; Fang, Mei-Juan; Wu, Zhen, E-mail: wuzhen@xmu.edu.cn

    2014-04-01

    Highlights: • Preparative MDLC system was developed for separation of complicated natural products. • Medium-pressure LC and preparative HPLC were connected by interface of SPE. • Automated multi-step preparative separation of 25 compounds was achieved by using this system. - Abstract: An on-line comprehensive two-dimensional preparative liquid chromatography system was developed for preparative separation of minor amount components from complicated natural products. Medium-pressure liquid chromatograph (MPLC) was applied as the first dimension and preparative HPLC as the second one, in conjunction with trapping column and makeup pump. The performance of the trapping column was evaluated, in terms of column size, dilution ratio and diameter-height ratio, as well as system pressure from the view of medium pressure liquid chromatograph. Satisfactory trapping efficiency can be achieved using a commercially available 15 mm × 30 mm i.d. ODS pre-column. The instrument operation and the performance of this MPLC × preparative HPLC system were illustrated by gram-scale isolation of crude macro-porous resin enriched water extract of Rheum hotaoense. Automated multi-step preparative separation of 25 compounds, whose structures were identified by MS, {sup 1}H NMR and even by less-sensitive {sup 13}C NMR, could be achieved in a short period of time using this system, exhibiting great advantages in analytical efficiency and sample treatment capacity compared with conventional methods.

  8. Interface analysis of Ge ultra thin layers intercalated between GaAs substrates and oxide stacks

    Energy Technology Data Exchange (ETDEWEB)

    Molle, Alessandro, E-mail: alessandro.molle@mdm.infm.i [Laboratorio Nazionale MDM, CNR-INFM, Via C. Olivetti 2, 20041 Agrate Brianza (Italy); Lamagna, Luca; Spiga, Sabina [Laboratorio Nazionale MDM, CNR-INFM, Via C. Olivetti 2, 20041 Agrate Brianza (Italy); Fanciulli, Marco [Laboratorio Nazionale MDM, CNR-INFM, Via C. Olivetti 2, 20041 Agrate Brianza (MI) (Italy); Dipartimento di Scienza dei Materiali, Universita di Milano Bicocca, Milano (Italy); Brammertz, Guy; Meuris, Marc [IMEC, 75 Kapeldreef, B-3001 Leuven (Belgium)

    2010-01-01

    Capping III-V compound surfaces with Ge ultra-thin layer might be a viable pathway to passivate the electrically active interface traps which usually jeopardize the integration of III-V materials in metal-oxide-semiconductor devices. As the physical nature of such traps is intrinsically related to the chemical details of the interface composition, the structural and compositional features of the Ge/GaAs interface were thoroughly investigated in two different configurations, the atomic layer deposition of La-doped ZrO{sub 2} films on Ge-capped GaAs and the ultra-high vacuum based molecular beam deposition of GeO{sub 2}/Ge double stack on in situ prepared GaAs. In the former case, the intercalation of a Ge interface layer is shown to suppress the concentration of interface Ga-O, As-O and elemental As bonding which were significantly detected in case of the direct oxide deposition on GaAs. In the latter case, the incidence of two different in situ surface preparations, the Ar sputtering and the atomic H cleaning, on the interface composition is elucidated and the beneficial role played by the atomic H exposure in reducing the semiconductor-oxygen bonds at the interface level is demonstrated.

  9. Amplitude various angles (AVA) phenomena in thin layer reservoir: Case study of various reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Nurhandoko, Bagus Endar B., E-mail: bagusnur@bdg.centrin.net.id, E-mail: bagusnur@rock-fluid.com [Wave Inversion and Subsurface Fluid Imaging Research Laboratory (WISFIR), Basic Science Center A 4" t" hfloor, Physics Dept., FMIPA, Institut Teknologi Bandung (Indonesia); Rock Fluid Imaging Lab., Bandung (Indonesia); Susilowati, E-mail: bagusnur@bdg.centrin.net.id, E-mail: bagusnur@rock-fluid.com [Rock Fluid Imaging Lab., Bandung (Indonesia)

    2015-04-16

    Amplitude various offset is widely used in petroleum exploration as well as in petroleum development field. Generally, phenomenon of amplitude in various angles assumes reservoir’s layer is quite thick. It also means that the wave is assumed as a very high frequency. But, in natural condition, the seismic wave is band limited and has quite low frequency. Therefore, topic about amplitude various angles in thin layer reservoir as well as low frequency assumption is important to be considered. Thin layer reservoir means the thickness of reservoir is about or less than quarter of wavelength. In this paper, I studied about the reflection phenomena in elastic wave which considering interference from thin layer reservoir and transmission wave. I applied Zoeppritz equation for modeling reflected wave of top reservoir, reflected wave of bottom reservoir, and also transmission elastic wave of reservoir. Results show that the phenomena of AVA in thin layer reservoir are frequency dependent. Thin layer reservoir causes interference between reflected wave of top reservoir and reflected wave of bottom reservoir. These phenomena are frequently neglected, however, in real practices. Even though, the impact of inattention in interference phenomena caused by thin layer in AVA may cause inaccurate reservoir characterization. The relation between classes of AVA reservoir and reservoir’s character are different when effect of ones in thin reservoir and ones in thick reservoir are compared. In this paper, I present some AVA phenomena including its cross plot in various thin reservoir types based on some rock physics data of Indonesia.

  10. Amplitude various angles (AVA) phenomena in thin layer reservoir: Case study of various reservoirs

    International Nuclear Information System (INIS)

    thfloor, Physics Dept., FMIPA, Institut Teknologi Bandung (Indonesia); Rock Fluid Imaging Lab., Bandung (Indonesia))" data-affiliation=" (Wave Inversion and Subsurface Fluid Imaging Research Laboratory (WISFIR), Basic Science Center A 4thfloor, Physics Dept., FMIPA, Institut Teknologi Bandung (Indonesia); Rock Fluid Imaging Lab., Bandung (Indonesia))" >Nurhandoko, Bagus Endar B.; Susilowati

    2015-01-01

    Amplitude various offset is widely used in petroleum exploration as well as in petroleum development field. Generally, phenomenon of amplitude in various angles assumes reservoir’s layer is quite thick. It also means that the wave is assumed as a very high frequency. But, in natural condition, the seismic wave is band limited and has quite low frequency. Therefore, topic about amplitude various angles in thin layer reservoir as well as low frequency assumption is important to be considered. Thin layer reservoir means the thickness of reservoir is about or less than quarter of wavelength. In this paper, I studied about the reflection phenomena in elastic wave which considering interference from thin layer reservoir and transmission wave. I applied Zoeppritz equation for modeling reflected wave of top reservoir, reflected wave of bottom reservoir, and also transmission elastic wave of reservoir. Results show that the phenomena of AVA in thin layer reservoir are frequency dependent. Thin layer reservoir causes interference between reflected wave of top reservoir and reflected wave of bottom reservoir. These phenomena are frequently neglected, however, in real practices. Even though, the impact of inattention in interference phenomena caused by thin layer in AVA may cause inaccurate reservoir characterization. The relation between classes of AVA reservoir and reservoir’s character are different when effect of ones in thin reservoir and ones in thick reservoir are compared. In this paper, I present some AVA phenomena including its cross plot in various thin reservoir types based on some rock physics data of Indonesia

  11. Sample collection and preparation of biofluids and extracts for gas chromatography-mass spectrometry.

    Science.gov (United States)

    Emwas, Abdul-Hamid M; Al-Talla, Zeyad A; Kharbatia, Najeh M

    2015-01-01

    To maximize the utility of gas chromatography-mass spectrometry (GC-MS) in metabonomics research, all stages of the experimental design should be standardized, including sample collection, storage, preparation, and sample separation. Moreover, the prerequisite for any GC-MS analysis is that a compound must be volatile and thermally stable if it is to be analyzed using this technique. Since many metabolites are nonvolatile and polar in nature, they are not readily amenable to analysis by GC-MS and require initial chemical derivatization of the polar functional groups in order to reduce the polarity and to increase the thermal stability and volatility of the analytes. In this chapter, an overview is presented of the optimum approach to sample collection, storage, and preparation for gas chromatography-mass spectrometry-based metabonomics with particular focus on urine samples as example of biofluids.

  12. Controlled crosslinking of trimethylolpropane trimethacrylate for preparation of organic monolithic columns for capillary liquid chromatography.

    Science.gov (United States)

    Gama, Mariana R; Aggarwal, Pankaj; Lee, Milton L; Bottoli, Carla B G

    2017-11-01

    Organic monolithic columns based on single crosslinking of trimethylolpropane trimethacrylate (TRIM) monomer were prepared in a single step by living/controlled free-radical polymerization. Full optimization of the preparation, such as using different percentages of TRIM and different amounts of radical promoter as well as various porogen solvents were explored. The resulting monolithic columns were characterized by scanning electronic microscopy and nitrogen sorption for structure morphology studies and surface area measurements, respectively. Using capillary liquid chromatography, 150 μm i.d. columns were applied to separate a mixture of small hydrophobic molecules. The results indicated that column performance is highly sensitive to the type and the amount of porogen solvents used in the polymerization mixture composition. Good resolution factors and methylene selectivity were obtained, indicating the promising potential of this material for capillary liquid chromatography separations. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Redox process at solid-liquid interfaces: studies with thin layers of green rusts electrodeposited on inert substrates

    International Nuclear Information System (INIS)

    Peulon, S.; Taghdai, Y.; Mercier, F.; Barre, N.; Legrand, L.; Chauss, A.

    2005-01-01

    Full text of publication follows: The redox reactions which can occur between radioelements and natural phases in the environment are taken still little into account although their importance is established on natural sites; the consequences are significant since they can modify radically the behaviour of the species by increasing or decreasing their migration. The iron compounds are very implicated in these redox processes because iron is one of the most abundant element on earth; moreover, it is also present in the containers used for the storage of the nuclear waste. We exhibited in previous works that electrochemistry is a convenient way to generate the main iron oxidation compounds as thin layers on different inert substrates. The electrochemical behaviour of these deposits that are adherent, homogeneous and well crystallized [1-3], was investigated with the principle advantage that iron metal and its reactivity is eliminate. Moreover, they could be analysed directly by techniques like IRRAS, XRD, SEM, EDS and XPS without any preparation. In the present study, we develop an original way to investigate redox processes at solid-liquid interfaces based on the utilisation of these thin layers; the samples are more commonly powders and/or pieces of corroded steel in the literature. Results obtained with two different systems, chromate and uranyl ions, in interaction with thin layers of sulfated green rusts are presented. Green rusts is chosen because it is a mixed Fe(II-III) compound which could be formed in anoxic conditions like in the case of the storage of the nuclear waste. After various contact times with the solutions containing the reactive species, the thin layers are characterised by different ex-situ methods. The results show clearly the oxidation of the green rust into a Fe(III) compound and the formation of a new solid phase on the electrode due to the reduction and the precipitation of the reactive species present initially in solution. Because thin

  14. Separation techniques: Chromatography

    Science.gov (United States)

    Coskun, Ozlem

    2016-01-01

    Chromatography is an important biophysical technique that enables the separation, identification, and purification of the components of a mixture for qualitative and quantitative analysis. Proteins can be purified based on characteristics such as size and shape, total charge, hydrophobic groups present on the surface, and binding capacity with the stationary phase. Four separation techniques based on molecular characteristics and interaction type use mechanisms of ion exchange, surface adsorption, partition, and size exclusion. Other chromatography techniques are based on the stationary bed, including column, thin layer, and paper chromatography. Column chromatography is one of the most common methods of protein purification. PMID:28058406

  15. Chromatography of phosphorus oxoacids

    International Nuclear Information System (INIS)

    Ohashi, S.

    1975-01-01

    The present state of studies on the chromatographic separation of phosphorus oxoacids is surveyed. In this paper, chromatographic techniques are divided into four groups, i.e. paper and thin-layer chromatography, paper electrophoresis, ion-exchange chromatography, and gel chromatography. The separation mechanisms and characteristics for these chromatographic methods are discussed and some examples for the separation of phosphorus oxoacids are described. As examples of the application of ion-exchange and gel chromatography, studies on the hot atom chemistry of 32 P in solid inorganic phosphates and those on the substitution reactions between diphosphonate (diphosphite) and polyphosphates are reported. (author)

  16. Considerations for Sample Preparation Using Size-Exclusion Chromatography for Home and Synchrotron Sources.

    Science.gov (United States)

    Rambo, Robert P

    2017-01-01

    The success of a SAXS experiment for structural investigations depends on two precise measurements, the sample and the buffer background. Buffer matching between the sample and background can be achieved using dialysis methods but in biological SAXS of monodisperse systems, sample preparation is routinely being performed with size exclusion chromatography (SEC). SEC is the most reliable method for SAXS sample preparation as the method not only purifies the sample for SAXS but also almost guarantees ideal buffer matching. Here, I will highlight the use of SEC for SAXS sample preparation and demonstrate using example proteins that SEC purification does not always provide for ideal samples. Scrutiny of the SEC elution peak using quasi-elastic and multi-angle light scattering techniques can reveal hidden features (heterogeneity) of the sample that should be considered during SAXS data analysis. In some cases, sample heterogeneity can be controlled using a small molecule additive and I outline a simple additive screening method for sample preparation.

  17. Separating esterase targets of organophosphorus compounds in the brain by preparative chromatography.

    Science.gov (United States)

    Mangas, I; Vilanova, E; Benabent, M; Estévez, J

    2014-02-10

    Low level exposure to organophosphorus esters (OPs) may cause long-term neurological effects and affect specific cognition domains in experimental animals and humans. Action on known targets cannot explain most of these effects by. Soluble carboxylesterases (EC 3.1.1.1) of chicken brain have been kinetically discriminated using paraoxon, mipafox and phenylmethyl sulfonylfluoride as inhibitors and phenyl valerate as a substrate. Three different enzymatic components were discriminated and called Eα, Eβ and Eγ. In this work, a fractionation procedure with various steps was developed using protein native separation methods by preparative HPLC. Gel permeation chromatography followed by ion exchange chromatography allowed enriched fractions with different kinetic behaviors. The soluble chicken brain fraction was fractionated, while total esterase activity, proteins and enzymatic components Eα, Eβ and Eγ were monitored in each subfraction. After the analysis, 13 fractions were pooled and conserved. Preincubation of the soluble chicken brain fraction of with the organophosphorus mipafox gave rise to a major change in the ion exchange chromatography profile, but not in the molecular exchanged chromatography profile, which suggest that mipafox permanently modifies the ionic properties of numerous proteins. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  18. Determination Of Refractive Index And Reflectivity Of Thin Layer With Optical Absorption Method; PENENTUAN INDEKS BIAS DAN REFLEKTIVITAS LAPISAN TIPIS DENGAN METODA SERAPAN OPTIK

    Energy Technology Data Exchange (ETDEWEB)

    Hariyanto, Sigit; Budianto, Anwar; Subarkah,; Atmono, Trimarji [Yogyakarta Nuclear Research Center, National Nuclear Energy Agency, Yogyakarta (Indonesia)

    1996-04-15

    . The refractive index and reflectivity of ASi:H and Si Ox thin layer have been observed by optical absorption methods. Measurement has been done after the preparation of optical system which consists of a halogen lamp light source, monochromator, sample and light detector. The Monochromator output showed that measured halogen lamp spectrum light is between 470 nm -750 nm. The maximum voltage of halogen lamp is 220 Volt, the output light increases in intensity while the wave length increases. The inclination of intensity decrease at the wave length of 725 nm. The result of the calculation of refractive index varies in accordance with the wave length. The average refractive index of ASi:H is nf a = 1.753. The total reflectivity of air-thin layer-substrate is Rt a = 0.315. The refractive index of Si Ox sample is nf b2.182 and the total reflectivity is Rt b=O,514.

  19. Thin layer model for nonlinear evolution of the Rayleigh-Taylor instability

    Science.gov (United States)

    Zhao, K. G.; Wang, L. F.; Xue, C.; Ye, W. H.; Wu, J. F.; Ding, Y. K.; Zhang, W. Y.

    2018-03-01

    On the basis of the thin layer approximation [Ott, Phys. Rev. Lett. 29, 1429 (1972)], a revised thin layer model for incompressible Rayleigh-Taylor instability has been developed to describe the deformation and nonlinear evolution of the perturbed interface. The differential equations for motion are obtained by analyzing the forces (the gravity and pressure difference) of fluid elements (i.e., Newton's second law). The positions of the perturbed interface are obtained from the numerical solution of the motion equations. For the case of vacuum on both sides of the layer, the positions of the upper and lower interfaces obtained from the revised thin layer approximation agree with that from the weakly nonlinear (WN) model of a finite-thickness fluid layer [Wang et al., Phys. Plasmas 21, 122710 (2014)]. For the case considering the fluids on both sides of the layer, the bubble-spike amplitude from the revised thin layer model agrees with that from the WN model [Wang et al., Phys. Plasmas 17, 052305 (2010)] and the expanded Layzer's theory [Goncharov, Phys. Rev. Lett. 88, 134502 (2002)] in the early nonlinear growth regime. Note that the revised thin layer model can be applied to investigate the perturbation growth at arbitrary Atwood numbers. In addition, the large deformation (the large perturbed amplitude and the arbitrary perturbed distributions) in the initial stage can also be described by the present model.

  20. Thin-layer voltammetry of soluble species on screen-printed electrodes: proof of concept.

    Science.gov (United States)

    Botasini, S; Martí, A C; Méndez, E

    2016-10-17

    Thin-layer diffusion conditions were accomplished on screen-printed electrodes by placing a controlled-weight onto the cast solution and allowing for its natural spreading. The restricted diffusive conditions were assessed by cyclic voltammetry at low voltage scan rates and electrochemical impedance spectroscopy. The relationship between the weight exerted over the drop and the thin-layer thickness achieved was determined, in such a way that the simple experimental set-up designed for this work could be developed into a commercial device with variable control of the thin-layer conditions. The experimental results obtained resemble those reported for the voltammetric features of electroactive soluble species employing electrodes modified with carbon nanotubes or graphene layers, suggesting that the attainment of the benefits reported for these nanomaterials could be done simply by forcing the solution to spread over the screen-printed electrodic system to form a thin layer solution. The advantages of thin-layer voltammetry in the kinetic characterization of quasi-reversible and irreversible processes are highlighted.

  1. Mathematical modeling of thin layer drying of pistachio by using solar energy

    Energy Technology Data Exchange (ETDEWEB)

    Midilli, A [University of Nigde (Turkey). Dept. of Mechanical Engineering; Kucuk, H [Karadeniz Technical Univ., Trabzon (Turkey). Dept. of Mechanical Engineering

    2003-05-01

    This paper presents a mathematical modeling of thin layer forced and natural solar drying of shelled and unshelled pistachio samples. In order to estimate and select the suitable form of solar drying curves, eight different mathematical models, which are semi-theoretical and/or empirical, were applied to the experimental data and compared according to their coefficients of determination (r,{chi}{sup 2}), which were predicted by non-linear regression analysis using the Statistical Computer Program. It was deduced that the logarithmic model could sufficiently describe thin layer forced solar drying of shelled and unshelled pistachio, while the two term model could define thin layer natural solar drying of these products in evaluation by considering the coefficients of determination, r{sub sfsd}=0.9983, {chi}{sup 2}{sub sfsd}=2.697x10{sup -5}; r{sub ufsd}=0.9990, {chi}{sup 2}{sub ufsd}=1.639x10{sup -5} for thin layer forced solar drying and r{sub snsd}=0.9990, {chi}{sup 2}{sub snsd}=3.212x10{sup -6}; r{sub unsd}=0.9970, {chi}{sup 2}{sub unsd}=4.590x10{sup -5} for thin layer natural solar drying. (Author)

  2. Studies of oxide-based thin-layered heterostructures by X-ray scattering methods

    Energy Technology Data Exchange (ETDEWEB)

    Durand, O. [Thales Research and Technology France, Route Departementale 128, F-91767 Palaiseau Cedex (France)]. E-mail: olivier.durand@thalesgroup.com; Rogers, D. [Nanovation SARL, 103 bis rue de Versailles 91400 Orsay (France); Universite de Technologie de Troyes, 10-12 rue Marie Curie, 10010 (France); Teherani, F. Hosseini [Nanovation SARL, 103 bis rue de Versailles 91400 Orsay (France); Andrieux, M. [LEMHE, ICMMOCNRS-UMR 8182, Universite d' Orsay, Batiment 410, 91410 Orsay (France); Modreanu, M. [Tyndall National Institute, Lee Maltings, Prospect Row, Cork (Ireland)

    2007-06-04

    Some X-ray scattering methods (X-ray reflectometry and Diffractometry) dedicated to the study of thin-layered heterostructures are presented with a particular focus, for practical purposes, on the description of fast, accurate and robust techniques. The use of X-ray scattering metrology as a routinely working non-destructive testing method, particularly by using procedures simplifying the data-evaluation, is emphasized. The model-independent Fourier-inversion method applied to a reflectivity curve allows a fast determination of the individual layer thicknesses. We demonstrate the capability of this method by reporting X-ray reflectometry study on multilayered oxide structures, even when the number of the layers constitutive of the stack is not known a-priori. Fast Fourier transform-based procedure has also been employed successfully on high resolution X-ray diffraction profiles. A study of the reliability of the integral-breadth methods in diffraction line-broadening analysis applied to thin layers, in order to determine coherent domain sizes, is also reported. Examples from studies of oxides-based thin-layers heterostructures will illustrate these methods. In particular, X-ray scattering studies performed on high-k HfO{sub 2} and SrZrO{sub 3} thin-layers, a (GaAs/AlOx) waveguide, and a ZnO thin-layer are reported.

  3. Layer chromatography-bioassays directed screening and identification of antibacterial compounds from Scotch thistle.

    Science.gov (United States)

    Móricz, Ágnes M; Krüzselyi, Dániel; Alberti, Ágnes; Darcsi, András; Horváth, Györgyi; Csontos, Péter; Béni, Szabolcs; Ott, Péter G

    2017-11-17

    The antibacterial profiling of Onopordum acanthium L. leaf extract and subsequent targeted identification of active compounds is demonstrated. Thin-layer chromatography (TLC) and off-line overpressured layer chromatography (OPLC) coupled with direct bioautography were utilized for investigation of the extract against eight bacterial strains including two plant and three human pathogens and a soil, a marine and a probiotic human gut bacteria. Antibacterial fractions obtaining infusion-transfusion OPLC were transferred to HPLC-MS/MS analysis that resulted in the characterization of three active compounds and two of them were identified as, linoleic and linolenic acid. OPLC method was adopted to preparative-scale flash chromatography for the isolation of the third active compound, which was identified after a further semi-preparative HPLC purification as the germacranolide sesquiterpene lactone onopordopicrin. Pure onopordopicrin exhibited antibacterial activity that was specified as minimal inhibitory concentration in the liquid phase as well. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Development of a simplified densitometer for the determination of aflatoxins by thin-layer chromatography.

    Science.gov (United States)

    Stroka, J; Anklam, E

    2000-12-29

    A simple, miniaturised and low power consuming (battery, fully semiconductor based) detector cell (SeBaDeC) was developed for the densitometric measurement of aflatoxins on TLC plates. A UV-light emitting diode (UV-LED) with a peak emission wavelength of 370 nm was used for fluorescence excitation, while a photo diode with a peak sensitivity of 440 nm in combination with a 418 nm cut-off filter was applied for detecting the fluorescence intensity. The resulting signal was further amplified by means of a commonly used operational amplifier integrated circuit (OA) and directly converted into a digital signal with a simple analogue-digital-converter (ADC). This signal was recorded at the serial (RS232) port of a portable PC and processed with a spreadsheet program. The software used for data recording is freeware and available in its source code, and the long lifetime of the UV-LED (up to 10 000 h) permits a maintenance free application of this device. This simplified device has shown to be able to detect concentrations of aflatoxins of 1 ng, thus offering a cheap and sensitive alternative to currently available TCL scanners.

  5. 21 CFR 862.2270 - Thin-layer chromatography system for clinical use.

    Science.gov (United States)

    2010-04-01

    ... SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Laboratory... equilibrium occurs between the two phases. (b) Classification. Class I (general controls). The device is...

  6. Detection of 14C - lindane metabolites in coffee plants by thin-layer chromatography and autoradiography

    International Nuclear Information System (INIS)

    Mesquita, T.B.; Hirata, R.; Ruegg, E.F.

    1986-01-01

    Immersion of seedling from coffee plants in aquous solution of 14 C - lindane was done for 60 days. The insecticide was taken up the roots and translocated to the stems and leaves. However, chromatographic assays indicated that several metabolites were detected only in the roots. Two of them probably are chlorobenzenes and were visualized in chromatograms of extracts from non-acidic fractions. Seven other radioactive spots which are suspected to be chlorophenols, were found in the acidic fractions. (Author) [pt

  7. The Mobile Phase Motion in Ascending Micellar Thin-Layer Chromatography with Normal-Phase Plates

    NARCIS (Netherlands)

    Boichenko, Alexander P.; Makhno, Iryna V.; Renkevich, Anton Yu.; Loginova, Lidia P.

    2011-01-01

    The physical chemical characteristics (surface tension and viscosity) of micellar mobile phases based on the cationic surfactant cetylpiridinium chloride and additives of alcohols (ethanol, 1-propanol, 1-butanol, 1-pentanol) have been obtained in this work. The effect of mobile phase properties on

  8. Ultra-thin layer chromatography with integrated silver colloid-based SERS detection.

    Science.gov (United States)

    Wallace, Ryan A; Lavrik, Nickolay V; Sepaniak, Michael J

    2017-01-01

    Simplified lab-on-a-chip techniques are desirable for quick and efficient detection of analytes of interest in the field. The following work involves the use of deterministic pillar arrays on the micro-scale as a platform to separate compounds, and the use of Ag colloid within the arrays as a source of increased signal via surface enhanced Raman spectroscopy (SERS). One problem traditionally seen with SERS surfaces containing Ag colloid is oxidation; however, our platforms are superhydrophobic, reducing the amount of oxidation taking place on the surface of the Ag colloid. This work includes the successful separation and SERS detection of a fluorescent dye compounds (resorufin and sulforhodamine 640), fluorescent anti-tumor drugs (Adriamycin and Daunomycin), and purine and pyrimidine bases (adenine, cytosine, guanine, hypoxanthine, and thymine). © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Analysis of biodiesel conversion using thin layer chromatography and nonlinear calibration curves

    DEFF Research Database (Denmark)

    Fedosov, Sergey; Brask, Jesper; Xu, Xuebing

    2011-01-01

    Biodiesel (BD) is a fuel produced by the (trans)esterification reaction between the components of vegetable oil (or animal fat) and an alcohol. The presence of several substrates complicates analytical separation of the mixture, yet understanding of the complex reaction kinetics requires acquisit......Biodiesel (BD) is a fuel produced by the (trans)esterification reaction between the components of vegetable oil (or animal fat) and an alcohol. The presence of several substrates complicates analytical separation of the mixture, yet understanding of the complex reaction kinetics requires...

  10. Validation of the FDG (18F) radiochemical purity assay by thin layer chromatography

    International Nuclear Information System (INIS)

    Leao, R.L.C.; Oliveira, M.L.; Nascimento, J.E.; Nascimento, N.C.E.S.

    2013-01-01

    All methodologies utilized in radiopharmaceutical industry should be validated in order to prove that they meet the requirements of analytical applications, ensuring the reliability of the results. At a radiopharmaceutical industry there is one challenge aspect: sometimes it is not possible use a stable standard to perform the validation analysis. In order to overcome this difficulty, the objective of this study was to suggest a validation protocol for these methodologies, based on the recommendations of RE n° 899/Agencia Nacional de Vigilancia Sanitaria (ANVISA), and prove its efficiency, performing the radiochemical purity validation test of FDG (18F), by TLC. To obtain the calibration curve, we suggested that the theoretical activity values should be determined using a dose calibrator, simultaneously of each analysis performed by TLC, for 5 hours. The method was linear (R 2 of 0.996), precise (CV% <5%) and accurate (96.85% < accuracy < 102.56%). In relation to the robustness test, our experiments evaluated the influence of the distance travelled by mobile phase, variations at mobile phase concentration and type of chromatographic plate (silica gel on glass or aluminium plates). The detection and quantification limits were determined (321.9 and 1065.6 kBq, respectively). As expected, this methodology was nonspecific, showing a slight spot corresponding to the FDM. The proposed protocol was efficient and the methodology tested was effective to determine the radiochemical purity of FDG (18F), in accordance to the limits recommended by ANVISA. (author)

  11. A simplified computing method of pile group to seismic loads using thin layer element

    International Nuclear Information System (INIS)

    Masao, T.; Hama, I.

    1995-01-01

    In the calculation of pile group, it is said that the results of response by thin layer method give the correct solution with the isotropic and homogeneous soil material in each layer, on the other hand this procedure spends huge computing time. Dynamic stiffness matrix of thin layer method is obtained from inversion of flexibility matrix between pile-i and pile-j. This flexibility matrix is full matrix and its size increase in proportion to the number of piles and thin layers. The greater part of run time is taken into the inversion of flexibility matrix against point loading. We propose the method of decreasing the run time for computing by reducing to banded matrix of flexibility matrix. (author)

  12. Bias of shear wave elasticity measurements in thin layer samples and a simple correction strategy.

    Science.gov (United States)

    Mo, Jianqiang; Xu, Hao; Qiang, Bo; Giambini, Hugo; Kinnick, Randall; An, Kai-Nan; Chen, Shigao; Luo, Zongping

    2016-01-01

    Shear wave elastography (SWE) is an emerging technique for measuring biological tissue stiffness. However, the application of SWE in thin layer tissues is limited by bias due to the influence of geometry on measured shear wave speed. In this study, we investigated the bias of Young's modulus measured by SWE in thin layer gelatin-agar phantoms, and compared the result with finite element method and Lamb wave model simulation. The result indicated that the Young's modulus measured by SWE decreased continuously when the sample thickness decreased, and this effect was more significant for smaller thickness. We proposed a new empirical formula which can conveniently correct the bias without the need of using complicated mathematical modeling. In summary, we confirmed the nonlinear relation between thickness and Young's modulus measured by SWE in thin layer samples, and offered a simple and practical correction strategy which is convenient for clinicians to use.

  13. Sorption and movement of pesticides on thin layer plates of Brazilain soils

    International Nuclear Information System (INIS)

    Lord, K.A.; Helene, C.G.; Andrea, M.M. de; Ruegg, E.F.

    1979-01-01

    The sorption from aqueous solution, and movement in water on thin layers plates of 7 soils of 3 organochlorine, 2 organophosphorus and 1 carbamate insecticide was determined in the laboratory. Generally, all substances were sorbed most and moved least on soils richest in organic matter. However, sorption was not a function of organic matter content alone. Aldrin and DDT were most strongly sorbed and did not move from the point of application on the thin layer plates of any soil. On all 7 soils, carbaryl was the least strongly sorbed insecticide. On 5 soils, lindane, parathion and malathion were increasingly strongly sorbed, but on the other 2 soils lindane was mostly strongly sorbed. The apparent greater mobility of 14 C-labelled malathion on thin layers of soils repeatedly leached could be explained by the formation of more polar substances. (author) [pt

  14. Preparative Separation of Phenolic Compounds from Halimodendron halodendron by High-Speed Counter-Current Chromatography

    OpenAIRE

    Wang, Jihua; Gao, Haifeng; Zhao, Jianglin; Wang, Qi; Zhou, Ligang; Han, Jianguo; Yu, Zhu; Yang, Fuyu

    2010-01-01

    Three phenolic compounds, p-hydroxybenzoic acid (1), isorhamnetin-3-O-β-D-rutinoside (2), and 3,3'-di-O-methylquercetin (5), along with a phenolic mixture were successfully separated from the ethyl acetate crude extract of Halimodendron halodendron by high-speed counter-current chromatography (HSCCC) with chloroform-methanol-water-acetic acid (4:3:2:0.05, v/v) as the two-phase solvent system. The phenolic mixture from HSCCC was further separated by preparative HPLC and purified by Sephadex LH...

  15. Photo-EMF sensitivity of porous silicon thin layer-crystalline silicon heterojunction to ammonia adsorption.

    Science.gov (United States)

    Vashpanov, Yuriy; Jung, Jae Il; Kwack, Kae Dal

    2011-01-01

    A new method of using photo-electromotive force in detecting gas and controlling sensitivity is proposed. Photo-electromotive force on the heterojunction between porous silicon thin layer and crystalline silicon wafer depends on the concentration of ammonia in the measurement chamber. A porous silicon thin layer was formed by electrochemical etching on p-type silicon wafer. A gas and light transparent electrical contact was manufactured to this porous layer. Photo-EMF sensitivity corresponding to ammonia concentration in the range from 10 ppm to 1,000 ppm can be maximized by controlling the intensity of illumination light.

  16. Nonequilibrium temperatures and second-sound propagation along nanowires and thin layers

    International Nuclear Information System (INIS)

    Jou, D.; Cimmelli, V.A.; Sellitto, A.

    2009-01-01

    It is shown that the dispersion relation of heat waves along nanowires or thin layers could allow to compare two different definitions of nonequilibrium temperature, since thermal waves are predicted to propagate with different phase speed depending on the definition of nonequilibrium temperature being used. The difference is small, but it could be in principle measurable in nanosystems, as for instance nanowires and thin layers, in a given frequency range. Such an experiment could provide a deeper view on the problem of the definition of temperature in nonequilibrium situations.

  17. Green sample preparation for liquid chromatography and capillary electrophoresis of anionic and cationic analytes.

    Science.gov (United States)

    Wuethrich, Alain; Haddad, Paul R; Quirino, Joselito P

    2015-04-21

    A sample preparation device for the simultaneous enrichment and separation of cationic and anionic analytes was designed and implemented in an eight-channel configuration. The device is based on the use of an electric field to transfer the analytes from a large volume of sample into small volumes of electrolyte that was suspended into two glass micropipettes using a conductive hydrogel. This simple, economical, fast, and green (no organic solvent required) sample preparation scheme was evaluated using cationic and anionic herbicides as test analytes in water. The analytical figures of merit and ecological aspects were evaluated against the state-of-the-art sample preparation, solid-phase extraction. A drastic reduction in both sample preparation time (94% faster) and resources (99% less consumables used) was observed. Finally, the technique in combination with high-performance liquid chromatography and capillary electrophoresis was applied to analysis of quaternary ammonium and phenoxypropionic acid herbicides in fortified river water as well as drinking water (at levels relevant to Australian guidelines). The presented sustainable sample preparation approach could easily be applied to other charged analytes or adopted by other laboratories.

  18. Integration of gas chromatography mass spectrometry methods for differentiating ricin preparation methods.

    Science.gov (United States)

    Wunschel, David S; Melville, Angela M; Ehrhardt, Christopher J; Colburn, Heather A; Victry, Kristin D; Antolick, Kathryn C; Wahl, Jon H; Wahl, Karen L

    2012-05-07

    The investigation of crimes involving chemical or biological agents is infrequent, but presents unique analytical challenges. The protein toxin ricin is encountered more frequently than other agents and is found in the seeds of Ricinus communis, commonly known as the castor plant. Typically, the toxin is extracted from castor seeds utilizing a variety of different recipes that result in varying purity of the toxin. Moreover, these various purification steps can also leave or differentially remove a variety of exogenous and endogenous residual components with the toxin that may indicate the type and number of purification steps involved. We have applied three gas chromatography-mass spectrometry (GC-MS) based analytical methods to measure the variation in seed carbohydrates and castor oil ricinoleic acid, as well as the presence of solvents used for purification. These methods were applied to the same samples prepared using four previously identified toxin preparation methods, starting from four varieties of castor seeds. The individual data sets for seed carbohydrate profiles, ricinoleic acid, or acetone amount each provided information capable of differentiating different types of toxin preparations across seed types. However, the integration of the data sets using multivariate factor analysis provided a clear distinction of all samples based on the preparation method, independent of the seed source. In particular, the abundance of mannose, arabinose, fucose, ricinoleic acid, and acetone were shown to be important differentiating factors. These complementary tools provide a more confident determination of the method of toxin preparation than would be possible using a single analytical method.

  19. Preparative separation of cacao bean procyanidins by high-speed counter-current chromatography.

    Science.gov (United States)

    Li, Lingxi; Zhang, Shuting; Cui, Yan; Li, Yuanyuan; Luo, Lanxin; Zhou, Peiyu; Sun, Baoshan

    2016-11-15

    In this work, an efficient method for preparative separation of procyanidins from raw cacao bean extract by high-speed counter-current chromatography (HSCCC) was developed. Under the optimized solvent system of n-hexane-ethyl acetate-water (1:50:50, v/v/v) with a combination of head-tail and tail-head elution modes, various procyanidins fractions with different polymerization degrees were successfully separated. UPLC, QTOF-MS and 1 H NMR analysis verified that these fractions contained monomer up to pentamer respectively. Dimeric procyanidin B2 (purity>86%) could be isolated by HSCCC in a single run. Other individual procyanidins in these fractions could be further isolated and purified by preparative HPLC. The developed HSCCC together with preparative HPLC techniques appeared to be a useful tool for large preparation of different procyanidins from cacao beans. Furthermore, by antioxidant activity assays, it was proved that both fractions and individual procyanidins possessed greater antioxidant activities compared to standard trolox. The antioxidant activities of procyanidins increase as the increase of their polymerization degree. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. A thin layer fiber-coupled luminescence dosimeter based on Al2O3:C

    DEFF Research Database (Denmark)

    Klein, F.A.; Greilich, Steffen; Andersen, Claus Erik

    2011-01-01

    In this paper we present a fiber-coupled luminescent Al2O3:C dosimeter probe with high spatial resolution (0.1 mm). It is based on thin layers of Al2O3:C crystal powder and a UV-cured acrylate monomer composition. The fabrication of the thin layers is described in detail. No influence of the intr......In this paper we present a fiber-coupled luminescent Al2O3:C dosimeter probe with high spatial resolution (0.1 mm). It is based on thin layers of Al2O3:C crystal powder and a UV-cured acrylate monomer composition. The fabrication of the thin layers is described in detail. No influence...... of the introduced polymer host matrix on the dosimetric properties was observed. Depth-dose measurements with the new detectors in a 142.66 MeV proton and 270.55 MeV/u carbon ion beam are presented as example applications. We used an RL protocol with saturated crystals allowing for time-effective measurements...... without sensitivity corrections. For protons, a relative luminescence efficiency hHCP of 0.715 0.014 was found in the Bragg peak. For carbon ions, a value of 0.498 0.001 was found in the entrance channel, 0.205 0.015 in the Bragg peak, and a mean of 0.413 0.050 in the tail region. The mean range...

  1. Copper(II) Schiff base complexes and their mixed thin layers with ...

    Indian Academy of Sciences (India)

    Thin layer; ZnO nanoparticles; copper complexes; AFM; SEM; fluorescence. 1. Introduction ... ZnO nanopowders29,30 and ZnO nanoparticles doped by different metal ...... Roy S, Choubey S, Bhar K, Khan S, Mitra P and Ghosh. B K 2013 J. Mol ...

  2. Oxidation effects on the electric resistance of In and Al in thin layers

    International Nuclear Information System (INIS)

    Moncada, G.; Araya, J.; Clark, N.

    1981-01-01

    Measurements of electric resistance (R) in function of the time in evaporated samples of thin layers of In and Al trivalent elements in both vacuum and atmospheric pressure are reported. Measurements in samples at ambient and cooled with nitrogen temperatures taken place. The changes observed in R is attributed partly to changes in the sample surface produced by the oxidation. (L.C.) [pt

  3. Thin-layer scanner with a dot printer recorder for radiolabelled compounds

    International Nuclear Information System (INIS)

    Kralova, M.; Kysela, F.; Hradil, Z.

    1982-01-01

    A scanner combined with a matrix printer is described for automatic evaluation of thin-layer radiochromatographs of soft beta emitters such as 3 H, 14 C, and 32 P. Details of the device including block schemes and electrical schemes are given

  4. Homogenization and dimension reduction of filtration combustion in heterogeneous thin layers

    NARCIS (Netherlands)

    Fatima, T.; Ijioma, E.R.; Ogawa, T.; Muntean, A.

    2014-01-01

    We study the homogenization of a reaction-diffusion-convection system posed in an e-periodic d-thin layer made of a two-component (solid-air) composite material. The microscopic system includes heat flow, diffusion and convection coupled with a nonlinear surface chemical reaction. We treat two

  5. Method for the manufacture of a thin-layer battery stack on a three-dimensional substrate

    NARCIS (Netherlands)

    2008-01-01

    The invention relates to a method for the manufacture of a thin-layer battery stack on a three-dimensional substrate. The invention further relates to a thin-layer battery stack on a three-dimensional substrate obtainable by such a method. Moreover, the invention relates to a device comprising such

  6. Separation of cis- and trans-Asarone from Acorus tatarinowii by Preparative Gas Chromatography

    Directory of Open Access Journals (Sweden)

    H. L. Zuo

    2012-01-01

    Full Text Available A preparative gas chromatography (pGC method was developed for the separation of isomers (cis- and trans-asarone from essential oil of Acorus tatarinowii. The oil was primarily fractionated by silica gel chromatography using different ratios of petroleum ether and ethyl acetate as gradient elution solvents. And then the fraction that contains mixture of the isomers was further separated by pGC. The compounds were separated on a stainless steel column packed with 10% OV-101 (3 m × 6 mm, i.d., and then the effluent was split into two gas flows. One percent of the effluent passed to the flame ionization detector (FID for detection and the remaining 99% was directed to the fraction collector. Two isomers were collected after 90 single injections (5 uL with the yield of 178 mg and 82 mg, respectively. Furthermore, the structures of the obtained compounds were identified as cis- and trans-asarone by 1H- and 13C-NMR spectra, respectively.

  7. Preparative Separation of Phenolic Compounds from Halimodendron halodendron by High-Speed Counter-Current Chromatography

    Directory of Open Access Journals (Sweden)

    Zhu Yu

    2010-08-01

    Full Text Available Three phenolic compounds, p-hydroxybenzoic acid (1, isorhamnetin-3-O-β-D-rutinoside (2, and 3,3'-di-O-methylquercetin (5, along with a phenolic mixture were successfully separated from the ethyl acetate crude extract of Halimodendron halodendron by high-speed counter-current chromatography (HSCCC with chloroform-methanol-water-acetic acid (4:3:2:0.05, v/v as the two-phase solvent system. The phenolic mixture from HSCCC was further separated by preparative HPLC and purified by Sephadex LH-20 to afford quercetin (3 and 3-O-methylquercetin (4. Seven hundred mg of ethyl acetate crude extract was separated by HSCCC to obtain six fractions which were then analyzed by high performance liquid chromatography (HPLC. The HSCCC separation obtained total of 80 mg of the mixture of quercetin (3 and 3-O-methylquercetin (4 (26.43% and 71.89%, respectively in fraction 2, 14 mg of 3,3'-di-O-methylquercetin (5 at 95.14% of purity in fraction 3, 15 mg of p-hydroxybenzoic acid (1 at 92.83% of purity in fraction 5, 12 mg of isorhamnetin-3-O-β-D-rutinoside (2 at 97.99% of purity in fraction 6. This is the first time these phenolic compounds have been obtained from H. halodendron, and their chemical structures identified by means of physicochemical and spectrometric analysis.

  8. Preparative separation of phenolic compounds from Halimodendron halodendron by high-speed counter-current chromatography.

    Science.gov (United States)

    Wang, Jihua; Gao, Haifeng; Zhao, Jianglin; Wang, Qi; Zhou, Ligang; Han, Jianguo; Yu, Zhu; Yang, Fuyu

    2010-08-31

    Three phenolic compounds, p-hydroxybenzoic acid (1), isorhamnetin-3-O-β-D-rutinoside (2), and 3,3'-di-O-methylquercetin (5), along with a phenolic mixture were successfully separated from the ethyl acetate crude extract of Halimodendron halodendron by high-speed counter-current chromatography (HSCCC) with chloroform-methanol-water-acetic acid (4:3:2:0.05, v/v) as the two-phase solvent system. The phenolic mixture from HSCCC was further separated by preparative HPLC and purified by Sephadex LH-20 to afford quercetin (3) and 3-O-methylquercetin (4). Seven hundred mg of ethyl acetate crude extract was separated by HSCCC to obtain six fractions which were then analyzed by high performance liquid chromatography (HPLC). The HSCCC separation obtained total of 80 mg of the mixture of quercetin (3) and 3-O-methylquercetin (4) (26.43% and 71.89%, respectively) in fraction 2, 14 mg of 3,3'-di-O-methylquercetin (5) at 95.14% of purity in fraction 3, 15 mg of p-hydroxybenzoic acid (1) at 92.83% of purity in fraction 5, 12 mg of isorhamnetin-3-O-β-D-rutinoside (2) at 97.99% of purity in fraction 6. This is the first time these phenolic compounds have been obtained from H. halodendron, and their chemical structures identified by means of physicochemical and spectrometric analysis.

  9. Enantioselective Analytical- and Preparative-Scale Separation of Hexabromocyclododecane Stereoisomers Using Packed Column Supercritical Fluid Chromatography

    Directory of Open Access Journals (Sweden)

    Nicole Riddell

    2016-11-01

    Full Text Available Hexabromocyclododecane (HBCDD is an additive brominated flame retardant which has been listed in Annex A of the Stockholm Convention for elimination of production and use. It has been reported to persist in the environment and has the potential for enantiomer-specific degradation, accumulation, or both, making enantioselective analyses increasingly important. The six main stereoisomers of technical HBCDD (i.e., the (+ and (− enantiomers of α-, β-, and γ-HBCDD were separated and isolated for the first time using enantioselective packed column supercritical fluid chromatography (pSFC separation methods on a preparative scale. Characterization was completed using published chiral liquid chromatography (LC methods and elution profiles, as well as X-ray crystallography, and the isolated fractions were definitively identified. Additionally, the resolution of the enantiomers, along with two minor components of the technical product (δ- and ε-HBCDD, was investigated on an analytical scale using both LC and pSFC separation techniques, and changes in elution order were highlighted. Baseline separation of all HBCDD enantiomers was achieved by pSFC on an analytical scale using a cellulose-based column. The described method emphasizes the potential associated with pSFC as a green method of isolating and analyzing environmental contaminants of concern.

  10. Enantioselective Analytical- and Preparative-Scale Separation of Hexabromocyclododecane Stereoisomers Using Packed Column Supercritical Fluid Chromatography.

    Science.gov (United States)

    Riddell, Nicole; Mullin, Lauren Gayle; van Bavel, Bert; Ericson Jogsten, Ingrid; McAlees, Alan; Brazeau, Allison; Synnott, Scott; Lough, Alan; McCrindle, Robert; Chittim, Brock

    2016-11-10

    Hexabromocyclododecane (HBCDD) is an additive brominated flame retardant which has been listed in Annex A of the Stockholm Convention for elimination of production and use. It has been reported to persist in the environment and has the potential for enantiomer-specific degradation, accumulation, or both, making enantioselective analyses increasingly important. The six main stereoisomers of technical HBCDD (i.e., the (+) and (-) enantiomers of α-, β-, and γ-HBCDD) were separated and isolated for the first time using enantioselective packed column supercritical fluid chromatography (pSFC) separation methods on a preparative scale. Characterization was completed using published chiral liquid chromatography (LC) methods and elution profiles, as well as X-ray crystallography, and the isolated fractions were definitively identified. Additionally, the resolution of the enantiomers, along with two minor components of the technical product (δ- and ε-HBCDD), was investigated on an analytical scale using both LC and pSFC separation techniques, and changes in elution order were highlighted. Baseline separation of all HBCDD enantiomers was achieved by pSFC on an analytical scale using a cellulose-based column. The described method emphasizes the potential associated with pSFC as a green method of isolating and analyzing environmental contaminants of concern.

  11. An Efficient Protocol for Preparation of Gallic Acid from Terminalia bellirica (Gaertn.) Roxb by Combination of Macroporous Resin and Preparative High-Performance Liquid Chromatography.

    Science.gov (United States)

    Zou, Denglang; Chen, Tao; Chen, Chen; Li, Hongmei; Liu, Yongling; Li, Yulin

    2016-08-01

    In this article, macroporous resin column chromatography and preparative high-performance liquid chromatography were applied for preparation of gallic acid from Terminalia bellirica (Gaertn.) Roxb. In the first step, six kinds of resins were investigated by adsorption and desorption tests and AB-8 macroporous resin was selected for the enrichment of gallic acid. As a result, 20 g of gallic acid at a purity of 71% could be separated from 100 g of crude extract in which the content of gallic acid was 16.7% and the recovery of gallic acid reached 85.0%. In the second step, preparative high-performance liquid chromatography was selected to purify gallic acid. As a result, 640 mg of gallic acid at a purity of 99.1% was obtained from 1 g of sample in 35 min. The results demonstrated that macroporous resin coupled with preparative high-performance liquid chromatography was suitable for preparation of gallic acid from T. bellirica (Gaertn.) Roxb. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  12. Use of large-scale chromatography in the preparation of armodafinil.

    Science.gov (United States)

    Hauck, Willy; Adam, Philippe; Bobier, Christelle; Landmesser, Nelson

    2008-08-01

    Armodafinil, the (R)-enantiomer of modafinil, is a medication used to treat the excessive sleepiness associated with narcolepsy, obstructive sleep apnea/hypopnea syndrome, and shift work sleep disorder. We report here the chemical development of armodafinil and the investigations that led to a commercial route to prepare this pure enantiomer. Three synthetic approaches were used to provide the chiral sulfoxide. Resolution via preferential crystallization was used for phase I clinical trials and was subsequently replaced by chiral chromatography, enabling us to pursue a rapid filing and registration of the API. Finally, the commercial route was developed and employed asymmetric oxidation catalyzed by a titanium(IV) isopropoxide and diethyl tartrate system. The advantages of choosing a chromatographic development pathway to expedite registration while concurrently developing an economical chiral synthesis route is discussed in the context of armodafinil development. (c) 2008 Wiley-Liss, Inc.

  13. Separation of krypton from dissolver off-gas of a reprocessing plant using preparative gas chromatography

    International Nuclear Information System (INIS)

    Matoni, M.

    1984-02-01

    Kr-85 can be separated from the pre-purified purge air in the final processing step of the purification phase for dissolver off-gases of a reprocessing plant with the aid of preparative gas chromatography. Activated carbon adsorbers in combination with helium as carrier gas permits maximum gas mixture through-flow. A separation temperature of 30 0 C is considered optimal. An adsorbent volume of 40 dm 3 is necessary for processing the residual gas flow of 2.5 Nm 3 /h; the adsorbent is divided between 2 columns linked in series each of which are 2 m long with an internal diameter of 100 mm. The helium flow required is five times greater than the off-gas flow. The degree of purity for krypton is greater than 90% for a decontamination factor of greater than 1000. (orig./HP) [de

  14. Stripping analysis of nanomolar perchlorate in drinking water with a voltammetric ion-selective electrode based on thin-layer liquid membrane.

    Science.gov (United States)

    Kim, Yushin; Amemiya, Shigeru

    2008-08-01

    A highly sensitive analytical method is required for the assessment of nanomolar perchlorate contamination in drinking water as an emerging environmental problem. We developed the novel approach based on a voltammetric ion-selective electrode to enable the electrochemical detection of "redox-inactive" perchlorate at a nanomolar level without its electrolysis. The perchlorate-selective electrode is based on the submicrometer-thick plasticized poly(vinyl chloride) membrane spin-coated on the poly(3-octylthiophene)-modified gold electrode. The liquid membrane serves as the first thin-layer cell for ion-transfer stripping voltammetry to give low detection limits of 0.2-0.5 nM perchlorate in deionized water, commercial bottled water, and tap water under a rotating electrode configuration. The detection limits are not only much lower than the action limit (approximately 246 nM) set by the U.S. Environmental Protection Agency but also are comparable to the detection limits of the most sensitive analytical methods for detecting perchlorate, that is, ion chromatography coupled with a suppressed conductivity detector (0.55 nM) or electrospray ionization mass spectrometry (0.20-0.25 nM). The mass transfer of perchlorate in the thin-layer liquid membrane and aqueous sample as well as its transfer at the interface between the two phases were studied experimentally and theoretically to achieve the low detection limits. The advantages of ion-transfer stripping voltammetry with a thin-layer liquid membrane against traditional ion-selective potentiometry are demonstrated in terms of a detection limit, a response time, and selectivity.

  15. Preparative separation of polyphenols from artichoke by polyamide column chromatography and high-speed counter-current chromatography

    International Nuclear Information System (INIS)

    Shu, Xikai; Wang, Mei; Liu, Daicheng; Wang, Daijie; Lin, Xiaojing; Liu, Jianhua; Wang, Xiao; Huang, Luqi

    2013-01-01

    An efficient method for the rapid separation and purification of polyphenols from artichoke by polyamide column chromatography in combination with high-speed counter-current chromatography (HSCCC) was successfully built. The crude ethanol extracts from dry artichoke were first pre-separated by polyamide column chromatography and divided in two parts as sample 1 and sample 2. Then, the samples were further separated by HSCCC and yielded 7.8 mg of chlorogenic acid (compound I), 24.5 mg of luteolin-7-O-β-D-rutinoside (compound II), 18.4 mg of luteolin-7-O-β-D-glucoside (compound III), and 33.4 mg of cynarin (compound IV) with purity levels of 92.0%, 98.2%, 98.5%, and 98.0%, respectively, as determined by high-performance liquid chromatography (HPLC) method. The chemical structures of these compounds were identified by electrospray ionization-mass spectrometry (ESI-MS) and nuclear magnetic resonance (NMR). (author)

  16. Preparative separation of polyphenols from artichoke by polyamide column chromatography and high-speed counter-current chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Shu, Xikai; Wang, Mei; Liu, Daicheng [College of Life Science, Shandong Normal University, Jinan, Shandong (China); Wang, Daijie; Lin, Xiaojing; Liu, Jianhua; Wang, Xiao; Huang, Luqi, E-mail: wxjn1998@126.com [Shandong Analysis and Test Center, Shandong Academy of Sciences, Jinan, Shandong (China)

    2013-09-01

    An efficient method for the rapid separation and purification of polyphenols from artichoke by polyamide column chromatography in combination with high-speed counter-current chromatography (HSCCC) was successfully built. The crude ethanol extracts from dry artichoke were first pre-separated by polyamide column chromatography and divided in two parts as sample 1 and sample 2. Then, the samples were further separated by HSCCC and yielded 7.8 mg of chlorogenic acid (compound I), 24.5 mg of luteolin-7-O-{beta}-D-rutinoside (compound II), 18.4 mg of luteolin-7-O-{beta}-D-glucoside (compound III), and 33.4 mg of cynarin (compound IV) with purity levels of 92.0%, 98.2%, 98.5%, and 98.0%, respectively, as determined by high-performance liquid chromatography (HPLC) method. The chemical structures of these compounds were identified by electrospray ionization-mass spectrometry (ESI-MS) and nuclear magnetic resonance (NMR). (author)

  17. High-performance thin-layer chromatographic fingerprints of isoflavonoids for distinguishing between Radix Puerariae Lobate and Radix Puerariae Thomsonii.

    Science.gov (United States)

    Chen, Si-Bao; Liu, He-Ping; Tian, Run-Tao; Yang, Da-Jian; Chen, Shi-Lin; Xu, Hong-Xi; Chan, Albert S C; Xie, Pei-Shan

    2006-07-14

    The roots of Pueraria lobata (Wild.) Ohwi and Pueraria thomsonii Benth have been officially recorded in all editions of Chinese Pharmacopoeia under the same monograph 'Gegen' (Radix Puerariae, RP). However, in its 2005 edition, the two species were separated into both individual monographs, namely 'Gegen' (Radix Puerariae Lobatae, RPL) and 'Fenge' (Radix Puerariae Thomsonii, RPT), respectively, due to their obvious content discrepancy of puerarin, the major active constituent. In present paper, the fingerprint of high-performance thin-layer chromatography (HPTLC) combining digital scanning profiling was developed to identify and distinguish the both species in detail. The unique properties of the HPTLC fingerprints were validated by analyzing ten batches of Pueraria lobata and P. thomsonii samples, respectively. The common pattern of the HPTLC images of the roots of Pueraria spp. and the respective different ratios of the chemical distribution can directly discern the two species. The corresponding digital scanning profiles provided an easy way for quantifiable comparison among the samples. Obvious difference in ingredient content and HPTLC patterns of the two species questioned their bio-equivalence and explained that recording both species separately in the current edition of Chinese Pharmacopoeia (2005 edition) is reasonable due to not only the content of major constituent, puerarin, but also the peak-to-peak distribution in the fingerprint and integration value of the total components. Furthermore, the HPTLC fingerprint is also suitable for rapid and simple authentication and comparison of the subtle difference among samples with identical plant resource but different geographic locations.

  18. Separation of Caffeine from Beverages and Analysis Using Thin-Layer Chromatography and Gas Chromatography-Mass Spectrometry

    Science.gov (United States)

    Torres y Torres, Janelle L.; Hiley, Shauna L.; Lorimor, Steven P.; Rhoad, Jonathan S.; Caldwell, Benjamin D.; Zweerink, Gerald L.; Ducey, Michael

    2015-01-01

    The Characterization and Analysis of a Product (CAP) project is used to introduce first-semester general chemistry students to chemical instrumentation through the analysis of caffeine-containing beverage products. Some examples of these products have included coffee, tea, and energy drinks. Students perform at least three instrumental experiments…

  19. [11C]-Flumazenil metabolites: Measurements of unchanged ligand in plasma using thin layer chromatography and rapid liquid chromatography

    International Nuclear Information System (INIS)

    Loc'h, C.; Hantraye, Ph.; Khalili-Varasteh, M.; Maziere, B.; Delforge, J.; Brouillet, E.; Syrota, A.; Maziere, M.

    1990-01-01

    To study in vivo benzodiazepine (BZ) receptors using PET, Flumazenil, an imidazobenzodiazepine with selective antagonistic actions, has been labeled with 11 C on its methyl group. The accurate determination of in vivo binding parameters using biomathematical models requires the knowledge of radioligand metabolism and the measurement of the plasmatic concentration of unchanged radioligand is mandatory. The present report describes and compares rapid and simple analytical procedures to measure unchanged [ 11 C]-Flumazenil in plasma

  20. Review of online coupling of sample preparation techniques with liquid chromatography.

    Science.gov (United States)

    Pan, Jialiang; Zhang, Chengjiang; Zhang, Zhuomin; Li, Gongke

    2014-03-07

    Sample preparation is still considered as the bottleneck of the whole analytical procedure, and efforts has been conducted towards the automation, improvement of sensitivity and accuracy, and low comsuption of organic solvents. Development of online sample preparation techniques (SP) coupled with liquid chromatography (LC) is a promising way to achieve these goals, which has attracted great attention. This article reviews the recent advances on the online SP-LC techniques. Various online SP techniques have been described and summarized, including solid-phase-based extraction, liquid-phase-based extraction assisted with membrane, microwave assisted extraction, ultrasonic assisted extraction, accelerated solvent extraction and supercritical fluids extraction. Specially, the coupling approaches of online SP-LC systems and the corresponding interfaces have been discussed and reviewed in detail, such as online injector, autosampler combined with transport unit, desorption chamber and column switching. Typical applications of the online SP-LC techniques have been summarized. Then the problems and expected trends in this field are attempted to be discussed and proposed in order to encourage the further development of online SP-LC techniques. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. On elastic waves in an thinly-layered laminated medium with stress couples under initial stress

    Directory of Open Access Journals (Sweden)

    P. Pal Roy

    1988-01-01

    Full Text Available The present work is concerned with a simple transformation rule in finding out the composite elastic coefficients of a thinly layered laminated medium whose bulk properties are strongly anisotropic with a microelastic bending rigidity. These elastic coefficients which were not known completely for a layered laminated structure, are obtained suitably in terms of initial stress components and Lame's constants λi, μi of initially isotropic solids. The explicit solutions of the dynamical equations for a prestressed thinly layered laminated medium under horizontal compression in a gravity field are derived. The results are discussed specifying the effects of hydrostatic, deviatoric and couple stresses upon the characteristic propagation velocities of shear and compression wave modes.

  2. Characterization of the porosity of silicon nitride thin layers by Electrochemical Impedance Spectroscopy

    International Nuclear Information System (INIS)

    Barrès, T.; Tribollet, B.; Stephan, O.; Montigaud, H.; Boinet, M.; Cohin, Y.

    2017-01-01

    Silicon nitride thin films are widely used as diffusion barriers within stacks in the glass industry but turn out to be porous at the nanometric scale. EIS measurements were conducted on SiNx thin layers deposited on a gold layer. An electrochemical model was established to fit the EIS measurements making use of data from other complementary techniques. In particular, Transmission Electron Microscopy was performed on these thin layers to determine the diameter and the qualitative morphology of the pores. A quantitative determination of the through-porosity of the layer was deduced from the EIS model and was in good agreement with TEM measurements. Moreover, combining EIS with local observations enabled inhomogeneities in the layer to be probed by highlighting a specific region in the layer.

  3. Mathematical modelling of the thin layer solar drying of banana, mango and cassava

    Energy Technology Data Exchange (ETDEWEB)

    Koua, Kamenan Blaise; Fassinou, Wanignon Ferdinand; Toure, Siaka [Laboratoire d' Energie Solaire, Universite de Cocody- Abidjan, 22 BP 582 Abidjan 22 (Ivory Coast); Gbaha, Prosper [Laboratoire d' Energie Nouvelle et Renouvelable, Institut National Polytechnique, Felix HOUPHOUET - BOIGNY de Yamoussoukro (Ivory Coast)

    2009-10-15

    The main objectives of this paper are firstly to investigate the behaviour of the thin layer drying of plantain banana, mango and cassava experimentally in a direct solar dryer and secondly to perform mathematical modelling by using thin layer drying models encountered in literature. The variation of the moisture content of the products studied and principal drying parameters are analysed. Seven statistical models, which are empirical or semi-empirical, are tested to validate the experimental data. A non-linear regression analysis using a statistical computer program is used to evaluate the constants of the models. The Henderson and Pabis drying model is found to be the most suitable for describing the solar drying curves of plantain banana, mango and cassava. The drying data of these products have been analysed to obtain the values of the effective diffusivity during the falling drying rate phase. (author)

  4. On-line comprehensive two-dimensional normal-phase liquid chromatography × reversed-phase liquid chromatography for preparative isolation of Peucedanum praeruptorum.

    Science.gov (United States)

    Wang, Xin-Yuan; Li, Jia-Fu; Jian, Ya-Mei; Wu, Zhen; Fang, Mei-Juan; Qiu, Ying-Kun

    2015-03-27

    A new on-line comprehensive preparative two-dimensional normal-phase liquid chromatography × reversed-phase liquid chromatography (2D NPLC × RPLC) system was developed for the separation of complicated natural products. It was based on the use of a silica gel packed medium-pressure column as the first dimension and an ODS preparative HPLC column as the second dimension. The two dimensions were connected with normal-phase (NP) and reversed-phase (RP) enrichment units, involving a newly developed airflow assisted adsorption (AAA) technique. The instrument operation and the performance of this NPLC × RPLC separation method were illustrated by gram-scale isolation of ethanol extract from the roots of Peucedanum praeruptorum. In total, 19 compounds with high purity were obtained via automated multi-step preparative separation in a short period of time using this system, and their structures were comprehensively characterized by ESI-MS, (1)H NMR, and (13)C NMR. Including two new compounds, five isomers in two groups with identical HPLC and TLC retention values were also obtained and identified by 1D NMR and 2D NMR. This is the first report of an NPLC × RPLC system successfully applied in an on-line preparative process. This system not only solved the interfacing problem of mobile-phase immiscibility caused by NP and RP separation, it also exhibited apparent advantages in separation efficiency and sample treatment capacity compared with conventional methods. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Phonon and electron temperature and non-Fourier heat transport in thin layers

    Energy Technology Data Exchange (ETDEWEB)

    Carlomagno, I.; Cimmelli, V.A. [Department of Mathematics, Computer Science and Economics, University of Basilicata, Campus Macchia Romana, Viale dell' Ateneo Lucano 10, 85100 Potenza (Italy); Sellitto, A. [Department of Industrial Engineering, University of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano (Italy)

    2017-04-15

    We present a thermodynamic model of heat conductor which allows for different temperatures of phonons and electrons. This model is applied to calculate the steady-state radial temperature profile in a circular thin layer. The compatibility of the obtained temperature profiles with the second law of thermodynamics is investigated in view of the requirement of positive entropy production and of a nonlocal constitutive equation for the entropy flux.

  6. A thin-layer liquid culture technique for the growth of Helicobacter pylori.

    Science.gov (United States)

    Joo, Jung-Soo; Park, Kyung-Chul; Song, Jae-Young; Kim, Dong-Hyun; Lee, Kyung-Ja; Kwon, Young-Cheol; Kim, Jung-Min; Kim, Kyung-Mi; Youn, Hee-Shang; Kang, Hyung-Lyun; Baik, Seung-Chul; Lee, Woo-Kon; Cho, Myung-Je; Rhee, Kwang-Ho

    2010-08-01

    Several attempts have been successful in liquid cultivation of Helicobaccter pylori. However, there is a need to improve the growth of H. pylori in liquid media in order to get affluent growth and a simple approach for examining bacterial properties. We introduce here a thin-layer liquid culture technique for the growth of H. pylori. A thin-layer liquid culture system was established by adding liquid media to a 90-mm diameter Petri dish. Optimal conditions for bacterial growth were investigated and then viability, growth curve, and released proteins were examined. Maximal growth of H. pylori was obtained by adding 3 mL of brucella broth supplemented with 10% horse to a Petri dish. H. pylori grew in both DMEM and RPMI-1640 supplemented with 10% fetal bovine serum and 0.5% yeast extract. Serum-free RPMI-1640 supported the growth of H. pylori when supplemented with dimethyl-beta-cyclodextrin (200 microg/mL) and 1% yeast extract. Under optimal growth, H. pylori grew exponentially for 28 hours, reaching a density of 3.4 OD(600) with a generation time of 3.3 hours. After 24 hours, cultures at a cell density of 1.0 OD(600) contained 1.3 +/- 0.1 x 10(9 )CFU/mL. gamma-Glutamyl transpeptidase, nuclease, superoxide dismutase, and urease were not detected in culture supernatants at 24 hours in thin-layer liquid culture, but were present at 48 hours, whereas alcohol dehydrogenase, alkylhydroperoxide reductase, catalase, and vacuolating cytotoxin were detected at 24 hours. Thin-layer liquid culture technique is feasible, and can serve as a versatile liquid culture technique for investigating bacterial properties of H. pylori.

  7. A demonstration of on-line plant corrosion monitoring using thin layer activation

    International Nuclear Information System (INIS)

    Asher, J.; Webb, J.W.; Wilkins, N.J.M.; Lawrence, P.F.; UKAEA Atomic Energy Research Establishment, Harwell. Materials Development Div.)

    1981-12-01

    The corrosion of a 1 inch water pipe in an evaporative cooling system has been monitored over three periods of plant operation using thin layer activation (TLA). The corrosion rate was followed at a sensitivity of about 1 μm and clearly reflected changes in plant operation. Examination of the test section after removal, both by autoradiography and metallography revealed the extent of corrosion and pitting over the active area. (author)

  8. Thin layer settling - a promising method for purifying industrial waste waters

    Energy Technology Data Exchange (ETDEWEB)

    Perevalov, V G; Kolokhmatova, N M; Malkina, I I; Smyslov, A I

    1979-01-01

    Proposed for removing oil and suspended substances from waste waters is a thin layer, tubular settler, whose elements are made from polyethylene pipes. The operational effectiveness of the settler on the average is 90-95%, the duration of the purification is 10-11 min, which is 1/12 of that in the most common and contemporary oil traps. The volume of the settler structure with this productivity may be reduced by 12 times.

  9. Preparation of factor VII concentrate using CNBr-activated Sepharose 4B immunoaffinity chromatography.

    Science.gov (United States)

    Mousavi Hosseini, Kamran; Nasiri, Saleh

    2015-01-01

    Factor VII concentrates are used in patients with congenital or acquired factor VII deficiency or treatment of hemophilia patients with inhibitors. In this research, immunoaffinity chromatography was used to purify factor VII from prothrombin complex (Prothrombin- Proconvertin-Stuart Factor-Antihemophilic Factor B or PPSB) which contains coagulation factors II, VII, IX and X. The aim of this study was to improve purity, safety and tolerability as a highly purified factor VII concentrate. PPSB was prepared using DEAE-Sephadex and was used as the starting material for purification of coagulation factor VII. Prothrombin complex was treated by solvent/detergent at 24°C for 6 h with constant stirring. The mixture of PPSB in the PBS buffer was filtered and then chromatographed using CNBr-activated Sepharose 4B coupled with specific antibody. Factors II, IX, VII, X and VIIa were assayed on the fractions. Fractions of 48-50 were pooled and lyophilized as a factor VII concentrate. Agarose gel electrophoresis was performed and Tween 80 was measured in the factor VII concentrate. Specific activity of factor VII concentrate increased from 0.16 to 55.6 with a purificationfold of 347.5 and the amount of activated factor VII (FVIIa) was found higher than PPSB (4.4-fold). RESULTS of electrophoresis on agarose gel indicated higher purity of Factor VII compared to PPSB; these finding revealed that factor VII migrated as alpha-2 proteins. In order to improve viral safety, solvent-detergent treatment was applied prior to further purification and nearly complete elimination of tween 80 (2 μg/ml). It was concluded that immuonoaffinity chromatography using CNBr-activated Sepharose 4B can be a suitable choice for large-scale production of factor VII concentrate with higher purity, safety and activated factor VII.

  10. Analysis of human serum by liquid chromatography-mass spectrometry: improved sample preparation and data analysis.

    Science.gov (United States)

    Govorukhina, N I; Reijmers, T H; Nyangoma, S O; van der Zee, A G J; Jansen, R C; Bischoff, R

    2006-07-07

    Discovery of biomarkers is a fast developing field in proteomics research. Liquid chromatography coupled on line to mass spectrometry (LC-MS) has become a powerful method for the sensitive detection, quantification and identification of proteins and peptides in biological fluids like serum. However, the presence of highly abundant proteins often masks those of lower abundance and thus generally prevents their detection and identification in proteomics studies. To perform future comparative analyses of samples from a serum bank of cervical cancer patients in a longitudinal and cross-sectional manner, methodology based on the depletion of high-abundance proteins followed by tryptic digestion and LC-MS has been developed. Two sample preparation methods were tested in terms of their efficiency to deplete high-abundance serum proteins and how they affect the repeatability of the LC-MS data sets. The first method comprised depletion of human serum albumin (HSA) on a dye ligand chromatographic and immunoglobulin G (IgG) on an immobilized Protein A support followed by tryptic digestion, fractionation by cation-exchange chromatography, trapping on a C18 column and reversed-phase LC-MS. The second method included depletion of the six most abundant serum proteins based on multiple immunoaffinity chromatography followed by tryptic digestion, trapping on a C18 column and reversed-phase LC-MS. Repeatability of the overall procedures was evaluated in terms of retention time and peak area for a selected number of endogenous peptides showing that the second method, besides being less time consuming, gave more repeatable results (retention time: <0.1% RSD; peak area: <30% RSD). Application of an LC-MS component detection algorithm followed by principal component analysis (PCA) enabled discrimination of serum samples that were spiked with horse heart cytochrome C from non-spiked serum and the detection of a concentration trend, which correlated to the amount of spiked horse heart

  11. Application of thin-layer Navier-Stokes equations near maximum lift

    Science.gov (United States)

    Anderson, W. K.; Thomas, J. L.; Rumsey, C. L.

    1984-01-01

    The flowfield about a NACA 0012 airfoil at a Mach number of 0.3 and Reynolds number of 1 million is computed through an angle of attack range, up to 18 deg, corresponding to conditions up to and beyond the maximum lift coefficient. Results obtained using the compressible thin-layer Navier-Stokes equations are presented as well as results from the compressible Euler equations with and without a viscous coupling procedure. The applicability of each code is assessed and many thin-layer Navier-Stokes benchmark solutions are obtained which can be used for comparison with other codes intended for use at high angles of attack. Reasonable agreement of the Navier-Stokes code with experiment and the viscous-inviscid interaction code is obtained at moderate angles of attack. An unsteady solution is obtained with the thin-layer Navier-Stokes code at the highest angle of attack considered. The maximum lift coefficient is overpredicted, however, in comparison to experimental data, which is attributed to the presence of a laminar separation bubble near the leading edge not modeled in the computations. Two comparisons with experimental data are also presented at a higher Mach number.

  12. Characterisation by optical spectroscopy of a plasma of depositions of thins layers

    International Nuclear Information System (INIS)

    Chouan, Yannick

    1984-01-01

    This research thesis reports a work which, by correlating emission and absorption spectroscopic measurements with properties of deposited thin layers, aimed at being a complement to works undertaken by a team in charge of the realisation of a flat screen. In a first part, the author reports the study of a cathodic pulverisation of a silicon target. He describes the experimental set-up, presents correlations obtained between plasma electric properties (target self-polarisation voltage), emission spectroscopic measurements (line profile and intensity) and absorption spectroscopic measurements (density of metastables), and the composition of deposited thin layers for two reactive pulverisation plasmas (Ar-H_2 and Ar-CH_4). The second part addresses the relationship between experimental conditions and spectroscopic characteristics (emission and absorption lines, excitation and rotation temperature) of a He-SiH_4 plasma. The author also determined the most adapted spectroscopic measurements to the 'control' of deposition, and which result in an optimisation of electronic properties and of the deposition rate for the hydrogenated amorphous silicon. The third part reports the characterisation of depositions. Electric and optic measurements are reported. Then, for both deposition techniques, the author relates the influence of experimental conditions to deposition properties and to spectroscopic diagnosis. The author finally presents static characteristics of a thin-layer-based transistor

  13. Voltammetric Thin-Layer Ionophore-Based Films: Part 2. Semi-Empirical Treatment.

    Science.gov (United States)

    Yuan, Dajing; Cuartero, Maria; Crespo, Gaston A; Bakker, Eric

    2017-01-03

    This work reports on a semiempirical treatment that allows one to rationalize and predict experimental conditions for thin-layer ionophore-based films with cation-exchange capacity read out with cyclic voltammetry. The transition between diffusional mass transport and thin-layer regime is described with a parameter (α), which depends on membrane composition, diffusion coefficient, scan rate, and electrode rotating speed. Once the thin-layer regime is fulfilled (α = 1), the membrane behaves in some analogy to a potentiometric sensor with a second discrimination variable (the applied potential) that allows one to operate such electrodes in a multianalyte detection mode owing to the variable applied ion-transfer potentials. The limit of detection of this regime is defined with a second parameter (β = 2) and is chosen in analogy to the definition of the detection limit for potentiometric sensors provided by the IUPAC. The analytical equations were validated through the simulation of the respective cyclic voltammograms under the same experimental conditions. While simulations of high complexity and better accuracy satisfactorily reproduced the experimental voltammograms during the forward and backward potential sweeps (companion paper 1), the semiempirical treatment here, while less accurate, is of low complexity and allows one to quite easily predict relevant experimental conditions for this emergent methodology.

  14. Separation of three anthraquinone glycosides including two isomers by preparative high-performance liquid chromatography and high-speed countercurrent chromatography from Rheum tanguticum Maxim. ex Balf.

    Science.gov (United States)

    Chen, Tao; Li, Hongmei; Zou, Denglang; Liu, Yongling; Chen, Chen; Zhou, Guoying; Li, Yulin

    2016-08-01

    Anthraquinone glycosides, such as chrysophanol 1-O-β-d-glucoside, chrysophanol 8-O-β-d-glucoside, and physion 8-O-β-d-glucoside, are the accepted important active components of Rheum tanguticum Maxim. ex Balf. due to their pharmacological properties: antifungal, antimicrobial, cytotoxic, and antioxidant activities. However, an effective method for the separation of the above-mentioned anthraquinone glycosides from this herb is not currently available. Especially, greater difficulty existed in the separation of the two isomers chrysophanol 1-O-β-d-glucoside and chrysophanol 8-O-β-d-glucoside. This study demonstrated an efficient strategy based on preparative high-performance liquid chromatography and high-speed countercurrent chromatography for the separation of the above-mentioned anthraquinone glycosides from Rheum tanguticum Maxim.ex Balf. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Preparative Separation of Six Rhynchophylla Alkaloids from Uncaria macrophylla Wall by pH-Zone Refining Counter-Current Chromatography

    OpenAIRE

    Zhang, Qinghai; Lin, Changhu; Duan, Wenjuan; Wang, Xiao; Luo, Aiqin

    2013-01-01

    pH-Zone refining counter-current chromatography was successfully applied to the preparative isolation and purification of six alkaloids from the ethanol extracts of Uncaria macrophylla Wall. Because of the low content of alkaloids (about 0.2%, w/w) in U. macrophylla Wall, the target compounds were enriched by pH-zone refining counter-current chromatography using a two-phase solvent system composed of petroleum ether–ethyl acetate–isopropanol–water (2:6:3:9, v/v), adding 10 mM triethylamine ...

  16. Preparation, radiochemical analysis and biodistribution of 99mTc-dihydrobis(1-pyrazolyl)borate

    International Nuclear Information System (INIS)

    Owunwanne, A.; Abdel-Dayem, H.; Yacoub, T.

    1987-01-01

    Optimum preparation of 99m Tc-dihydrobis(1-pyrazolyl)borate ( 99m Tc-HBPz 2 ) was done by mixing 1.4 mg/ml HBPz 2 and 1.0 mg/ml of stanous PYP. Radiochemical analysis of the preparation using paper chromatography (PC), thin layer chromatography (TLC) and high performance liquid chromatography (HPLC) indicated a stable product with one major component. The labelling efficiency was approximately 90%. Animal biodistribution studies performed in mice showed that most of the injected radioactivity was confined to the liver, kidney, lungs, intestine and heart. The heart to blood ratio was small but persisted up to 3 hrs. after the injection. (orig.) [de

  17. Monolith Chromatography as Sample Preparation Step in Virome Studies of Water Samples.

    Science.gov (United States)

    Gutiérrez-Aguirre, Ion; Kutnjak, Denis; Rački, Nejc; Rupar, Matevž; Ravnikar, Maja

    2018-01-01

    Viruses exist in aquatic media and many of them use this media as transmission route. Next-generation sequencing (NGS) technologies have opened new doors in virus research, allowing also to reveal a hidden diversity of viral species in aquatic environments. Not surprisingly, many of the newly discovered viruses are found in environmental fresh and marine waters. One of the problems in virome research can be the low amount of viral nucleic acids present in the sample in contrast to the background ones (host, eukaryotic, prokaryotic, environmental). Therefore, virus enrichment prior to NGS is necessary in many cases. In water samples, an added problem resides in the low concentration of viruses typically present in aquatic media. Different concentration strategies have been used to overcome such limitations. CIM monoliths are a new generation of chromatographic supports that due to their particular structural characteristics are very efficient in concentration and purification of viruses. In this chapter, we describe the use of CIM monolithic chromatography for sample preparation step in NGS studies targeting viruses in fresh or marine water. The step-by-step protocol will include a case study where CIM concentration was used to study the virome of a wastewater sample using NGS.

  18. Recent advancements and future trends in environmental analysis: Sample preparation, liquid chromatography and mass spectrometry.

    Science.gov (United States)

    Pérez-Fernández, Virginia; Mainero Rocca, Lucia; Tomai, Pierpaolo; Fanali, Salvatore; Gentili, Alessandra

    2017-08-29

    Among the thousands of chemicals having potential to enter the environment, the NORMAN network has identified at least 700 substances categorized into 20 classes in the European surface waters. Pesticides, pharmaceuticals, disinfection by-products, wood preservation and industrial chemicals are the prominent classes. Since the impact of these substances on aquatic life and human health might be dramatic, action is urgently required at multiple levels; one of them is just related to the development of more and more sensible and selective analytical methods. This review highlights the latest advancements and trends in liquid chromatography-mass spectrometry based environmental analysis. Specific sections are dedicated to novelties in sample preparation, chromatographic separation and mass spectrometry detection of emerging pollutants. The review also offers insights on last generation chromatographic and extraction materials, technological progresses and innovative methodological approaches for target and non-target analysis. As numerous papers have been published in this field, this overview covers the most representative and original works published in the 2011-2016 period. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Preparation and purification of Flavobacterium heparinum chondroitinases AC and B by hydrophobic interaction chromatography

    Directory of Open Access Journals (Sweden)

    Aguiar J.A.K.

    1999-01-01

    Full Text Available Flavobacterium heparinum is a soil bacterium that produces several mucopolysaccharidases such as heparinase, heparitinases I and II, and chondroitinases AC, B, C and ABC. The purpose of the present study was to optimize the preparation of F. heparinum chondroitinases, which are very useful tools for the identification and structural characterization of chondroitin and dermatan sulfates. We observed that during the routine procedure for cell disruption (ultrasound, 100 kHz, 5 min some of the chondroitinase B activity was lost. Using milder conditions (2 min, most of the chondroitinase B and AC protein was solubilized and the enzyme activities were preserved. Tryptic soy broth without glucose was the best culture medium both for bacterial growth and enzyme induction. Chondroitinases AC and B were separated from each other and also from glucuronidases and sulfatases by hydrophobic interaction chromatography on HP Phenyl-Sepharose. A rapid method for screening of the column fractions was also developed based on the metachromatic shift of the color of dimethylmethylene blue.

  20. Preparative separation and purification of rosmarinic acid from perilla seed meal via combined column chromatography.

    Science.gov (United States)

    Tang, Weizhuo; Sun, Baoshan; Zhao, Yuqing

    2014-02-01

    In this study, the preparative separation and purification of rosmarinic acid (RA) from perilla seed meal (PSM), which is a by-product of edible oil production, was achieved using combined column chromatography over macroporous and polyamide resins. To optimize the RA enrichment process, the performance and separation characteristics of nine selected macroporous resins with different chemical and physical properties were investigated. SP825 resin was the most effective: the content of RA increased from 0.27% in the original extract to 16.58% in the 50% ethanol fraction (a 61.4-fold increase). During further purification treatment on polyamide resin, 90.23% pure RA could be obtained in the 70% ethanol fraction. RA with a higher purity (>95%) could also be easily obtained using one crystallization operation. The proposed method is simple, easily operated, cost-effective, and environmentally friendly and is suitable for both large-scale RA production and waste management. Copyright © 2013 Elsevier B.V. All rights reserved.

  1. Aminopropyl-functionalized ethane-bridged periodic mesoporous organosilica spheres: preparation and application in liquid chromatography.

    Science.gov (United States)

    Li, Chun; Di, Bin; Hao, Weiqiang; Yan, Fang; Su, Mengxiang

    2011-01-21

    A synthetic approach for synthesizing spherical aminopropyl-functionalized ethane-bridged periodic mesoporous organosilicas (APEPMOs) is reported. The mesoporous material was prepared by a one-step co-condensation of 1,2-bis(triethoxysilyl)ethane (BTSE) and 3-aminopropyltriethoxysilane (APTES) using cetyltrimethylammonium chlorine (C(18)TACl) as a template with the aid of a co-solvent (methanol) in basic medium. The APEPMOs were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), powder X-ray diffraction (XRD), nitrogen sorption measurement, Fourier transform infrared spectroscopy (FT-IR) and elemental analysis. It was shown that this material exhibited spherical morphology, ordered cubic mesostructure and good mechanical strength. The APEPMOs were tested as a potential stationary phase for liquid chromatography (LC) because the column exhibited reduced back pressure. Moreover, they exhibited good chemical stability in basic mobile phase, which can be ascribed to the ethane groups in the mesoporous framework. Copyright © 2010 Elsevier B.V. All rights reserved.

  2. Application and comparison of high-speed countercurrent chromatography and high performance liquid chromatography in preparative enantioseparation of α-substitution mandelic acids.

    Science.gov (United States)

    Tong, Shengqiang; Zhang, Hu; Shen, Mangmang; Ito, Yoichiro; Yan, Jizhong

    2015-04-01

    Preparative enantioseparations of α-cyclopentylmandelic acid and α-methylmandelic acid by high-speed countercurrent chromatography (HSCCC) and high performance liquid chromatography (HPLC) were compared using hydroxypropy-β-cyclodextrin (HP-β-CD) and sulfobutyl ether-β-cyclodextrin (SBE-β-CD) as the chiral mobile phase additives. In preparative HPLC the enantioseparation was achieved on the ODS C 18 reverse phase column with the mobile phase composed of a mixture of acetonitrile and 0.10 mol L -1 phosphate buffer at pH 2.68 containing 20 mmol L -1 HP-β-CD for α-cyclopentylmandelic acid and 20 mmol L -1 SBE-β-CD for α-methylmandelic acid. The maximum sample size for α-cyclopentylmandelic acid and α-methylmandelic acid was only about 10 mg and 5 mg, respectively. In preparative HSCCC the enantioseparations of these two racemates were performed with the two-phase solvent system composed of n -hexane-methyl tert. -butyl ether-0.1 molL -1 phosphate buffer solution at pH 2.67 containing 0.1 mol L -1 HP-β-CD for α-cyclopentylmandelic acid (8.5:1.5:10, v/v/v) and 0.1 mol L -1 SBE-β-CD for α-methylmandelic acid (3:7:10, v/v/v). Under the optimum separation conditions, total 250 mg of racemic α-cyclopentylmandelic acid could be completely enantioseparated by HSCCC with HP-β-CD as a chiral mobile phase additive in a single run, yielding 105-110 mg of enantiomers with 95-98% purity and 85-90% recovery. But, no complete enantioseparation of α-methylmandelic acid was achieved by preparative HSCCC with either of the chiral selectors due to their limited enantioselectivity. In this paper preparative enantioseparation by HSCCC and HPLC was compared from various aspects.

  3. Preparation of thin layer deposits of actinides for studies in nuclear physics and solid state physics

    International Nuclear Information System (INIS)

    Kwinta, J.; Brossard, P.; Michel, J.J.; Thoreux, J.

    1983-09-01

    Two methods of deposition are described electrospraying and spraying with a ion beam. In the first method a solution is send through a capillary containing an electrode at a positive potential in respect to the support of the coating. In the second method ions (generally rare gases) produced by a source are accelerated and focussed with an electrostatic lens on the material to pulverize. Both are complementary to classical methods like electrodeposition and vacuum vaporization which are difficult to use in the case of rare isotopes [fr

  4. Preparation of polymer monolithic column functionalized by arsonic acid groups for mixed-mode capillary liquid chromatography.

    Science.gov (United States)

    Qin, Zhang-Na; Yu, Qiong-Wei; Wang, Ren-Qi; Feng, Yu-Qi

    2018-04-27

    A mixed-mode polymer monolithic column functionalized by arsonic acid groups was prepared by single-step in situ copolymerization of monomers p-methacryloylaminophenylarsonic acid (p-MAPHA) and pentaerythritol triacrylate (PETA). The prepared poly(p-MAPHA-co-PETA) monolithic column has a homogeneous monolithic structure with good permeability and mechanical stability. Zeta potential measurements reveal that the monolithic stationary phase holds a negative surface charge when the mobile phase resides in the pH range of 3.0-8.0. The retention mechanisms of prepared monolithic column are explored by the separation of selected polycyclic aromatic hydrocarbons (PAHs), nucleosides, and three basic compounds. The results indicate that the column functions in three different separation modes associated with reversed-phase chromatography based on hydrophobic interaction, hydrophilic interaction chromatography, and cation-exchange chromatography. The column efficiency of prepared monolithic column is estimated to be 70,000 and 76,000 theoretical plates/m for thiourea and naphthalene, respectively, at a linear flow velocity of 0.85 mm/s using acetonitrile/H 2 O (85/15, v/v) as the mobile phase. Furthermore, an analysis of the retention factors obtained for the PAHs indicates that the prepared monolithic column exhibits good reproducibility with relative standard deviations of 2.9%, 4.0%, and 4.7% based on run-to-run injections, column-to-column preparation, and batch-to-batch preparation, respectively. Finally, we investigate the separation performance of the proposed monolithic column for select phenols, sulfonamides, nucleobases and nucleosides. Copyright © 2018 Elsevier B.V. All rights reserved.

  5. Efficient separation of curcumin, demethoxycurcumin, and bisdemethoxycurcumin from turmeric using supercritical fluid chromatography: From analytical to preparative scale.

    Science.gov (United States)

    Song, Wei; Qiao, Xue; Liang, Wen-fei; Ji, Shuai; Yang, Lu; Wang, Yuan; Xu, Yong-wei; Yang, Ying; Guo, De-an; Ye, Min

    2015-10-01

    Curcumin is the major constituent of turmeric (Curcuma longa L.). It has attracted widespread attention for its anticancer and anti-inflammatory activities. The separation of curcumin and its two close analogs, demethoxycurcumin and bisdemethoxycurcumin, has been challenging by conventional techniques. In this study, an environmentally friendly method based on supercritical fluid chromatography was established for the rapid and facile separation of the three curcuminoids directly from the methanol extract of turmeric. The method was first developed and optimized by ultra performance convergence chromatography, and was then scaled up to preparative supercritical fluid chromatography. Eluted with supercritical fluid CO2 containing 8-15% methanol (containing 10 mM oxalic acid) at a flow rate of 80 mL/min, curcumin, demethoxycurcumin and bisdemethoxycurcumin could be well separated on a Viridis BEH OBD column (Waters, 250 mm × 19 mm, 5 μm) within 6.5 min. As a result, 20.8 mg of curcumin (97.9% purity), 7.0 mg of demethoxycurcumin (91.1%), and 4.6 mg of bisdemethoxycurcumin (94.8%) were obtained after a single step of supercritical fluid chromatography separation with a mean recovery of 76.6%. Showing obvious advantages in low solvent consumption, large sample loading, and easy solvent removal, supercritical fluid chromatography was proved to be a superior technique for the efficient separation of natural products. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. On Rayleigh waves in a thinly layered laminated thermoelastic medium with stress couples under initial stresses

    Directory of Open Access Journals (Sweden)

    Pijush Pal Roy

    1988-01-01

    Full Text Available A study is made of the propagation of Rayleigh waves in a thinly layered laminated thermoelastic medium under deviatoric, hydrostatic, and couple stresses. The frequency equation of the Rayleigh waves is obtained. The phase velocity of the Rayleigh waves depends on the initial stress, deviatoric stress, and the couple stress. The laminated medium is first replaced by an equivalent anisotropic thermoelastic continuum. The corresponding thermoelastic coefficients (after deformation are derived in terms of initially isotropic thermoelastic coefficients (before deformation of individual layers. Several particular cases are discussed for the determination of the displacement fields with or without the effect of the couple stress.

  7. MODELLING OF THIN LAYER DRYING KINETICS OF COCOA BEANS DURING ARTIFICIAL AND NATURAL DRYING

    Directory of Open Access Journals (Sweden)

    C.L. HII

    2008-04-01

    Full Text Available Drying experiments were conducted using air-ventilated oven and sun dryer to simulate the artificial and natural drying processes of cocoa beans. The drying data were fitted with several published thin layer drying models. A new model was introduced which is a combination of the Page and two-term drying model. Selection of the best model was investigated by comparing the determination of coefficient (R2, reduced chi-square (2 and root mean square error (RMSE between the experimental and predicted values. The results showed that the new model was found best described the artificial and natural drying kinetics of cocoa under the conditions tested.

  8. Laser sintered thin layer graphene and cubic boron nitride reinforced nickel matrix nanocomposites

    Science.gov (United States)

    Hu, Zengrong; Tong, Guoquan

    2015-10-01

    Laser sintered thin layer graphene (Gr)-cubic boron nitride (CBN)-Ni nanocomposites were fabricated on AISI 4140 plate substrate. The composites fabricating process, composites microstructure and mechanical properties were studied. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and Raman spectroscopy were employed to study the micro structures and composition of the composites. XRD and Raman tests proved that graphene and CBN were dispersed in the nanocomposites. Nanoindentation test results indicate the significant improvements were achieved in the composites mechanical properties.

  9. Thermal diffusivity of a metallic thin layer using the time-domain thermo reflectance technique

    International Nuclear Information System (INIS)

    Battaglia, J-L; Kusiak, A; Rossignol, C; Chigarev, N

    2007-01-01

    The time domain thermo reflectance (TDTR) is widely used in the field of acoustic and thermal characterization of thin layers at the nano and micro scale. In this paper, we propose to derive a simple analytical expression of the thermal diffusivity of the layer. This relation is based on the analytical solution of one-dimensional heat transfer in the medium using integral transforms. For metals, the two-temperature model shows that the capacitance effect at the short times is essentially governed by the electronic contribution

  10. Preparative separation of chlorogenic acid by centrifugal partition chromatography from highbush blueberry leaves (Vaccinium corymbosum L.).

    Science.gov (United States)

    Kim, Sang-Min; Shang, Ya Fang; Um, Byung-Hun

    2010-01-01

    Blueberries (genus Vaccinium) have gained worldwide focus because of the high anthocyanin content of their fruits. In contrast, the leaves of blueberry have not attracted any attention, even though they contain large quantities of chlorogenic acid, a strong antioxidant compound. The aim of this investigation was the quantification and preparative isolation of chlorogenic acid (5-caffeoylquinic acid, 5-CQA) from blueberry leaves using a new separation scheme, centrifugal partition chromatography (CPC). A water fraction containing a high concentration of 5-CQA (14.5% of dry weight extract) was obtained by defatting a crude methanol extract from blueberry leaves. CPC was applied to isolate 5-CQA from this water fraction using a two-phase solvent system of ethyl acetate-ethanol-water at a volume ratio 4:1:5 (v/v/v). The flow-rate of mobile phase was 2 mL/min with the ascending mode while rotating at 1200 rpm. The eluate was monitored at 330 nm. The structure of chlorogenic acid in the CPC fraction was confirmed with HPLC, UV, ESI/MS and NMR spectra. The HPLC chromatogram showed that the fractions collected by CPC contained chlorogenic acid with 96% purity based on peak area percentage. The total amount of chlorogenic acid isolated from 0.5 g of a water fraction was 52.9 mg, corresponding to 10.6% of the water fraction. The isolated compound was identified successively as 5-CQA with MS (parent ion at m/z 355.1 [M + H](+)) and (1)H NMR spectra [caffeoyl moiety in the down field (δ 6.0-8.0 ppm) and quinic acid moiety in the up field (δ 2.0-5.5 ppm)]. 5-CQA was successfully isolated from blueberry leaves by the CPC method in a one-step procedure, indicating a further potential use for blueberry leaves. Copyright © 2010 John Wiley & Sons, Ltd.

  11. Comparison of two detection methods in thin layer chromatographic analysis of some herbicides in a coastal savannah soil in Ghana

    International Nuclear Information System (INIS)

    Afful, S.; Yeboah, P.O.; Dogbe, S.A.; Akpabli, C.K.

    2008-01-01

    o-tolidine plus potassium iodide and photosynthesis inhibition detection methods were investigated for the analysis of three triazine herbicides (atrazine, ametryne, simazine) and two urea herbicides (diuron, metbromuron) in a coastal savannah soil using thin layer chromatography to compare the suitability of the two methods for the study of the herbicides. This was done by spiking 5 g of the soil sample with specific amount of the herbicide standards to generate herbicide-soil concentration of 40.24, 41.46, 40.28, 39.90 and 40.64 μg/g for atrazine, ametryne, simazine, diuron and metbromuron, respectively. Extraction was performed with acetone/hexane mixture (4:1) and the detection limit of each herbicide was then determined. In all, the photosynthesis inhibition method performed better for both the triazine and the urea herbicides, while the o-tolidine plus potassium iodide method was suitable for only the triazine herbicides. With the photosynthesis inhibition method, detectability in the range of 0.004-0.008 ± 0.002 μg/g was attained for the herbicides using the unclean extracts. In the case of o-tolidine plus potassium iodide method, detectability of 0.008-0.406 ± 0.02 μg/g was obtained. With the clean up extracts detectability in the range of 0.025-0.162 ± 0.004 μg/g was obtained using the photosynthesis inhibition method. However, metbromuron was not detected in the cleaned up extracts when o-tolidine plus potassium iodide detection method was used. For the methods described, clean up with SPE cartridge, equipped with C-18, is not critical to obtain the desired results. (au)

  12. Thin layer drying characteristics of curry leaves (Murraya koenigii in an indirect solar dryer

    Directory of Open Access Journals (Sweden)

    Vijayan Selvaraj

    2017-01-01

    Full Text Available In this work, the thin layer drying characteristics of curry leaves (Murraya koenigii has been studied in an indirect forced convection solar dryer with constant air mass flow rate of 0.0636 kg/s. Twelve thin layer drying models were tested for its suitability to describe the drying characteristics of curry leaves. The dryer has reduced the initial moisture content of curry leaves from 67.3% (wet basis to the final moisture content of 4.75% (wet basis in 3.5 hours. The pickup efficiency of indirect solar dryer for drying curry leaves was varied between 4.9% and 23.02%. Based on the statistical parameters, the Modified Henderson and Pabis model and Wang and Singh model were selected for predicting the drying characteristics of curry leaves. The payback period for the solar dryer was evaluated as 8 months, which is found to be much lower when compared with the entire life span of 15 years. The payback evaluation confirms that the solar dryer is economically viable in rural applications.

  13. Desorption isotherms and mathematical modeling of thin layer drying kinetics of tomato

    Science.gov (United States)

    Belghith, Amira; Azzouz, Soufien; ElCafsi, Afif

    2016-03-01

    In recent years, there is an increased demand on the international market of dried fruits and vegetables with significant added value. Due to its important production, consumption and nutrient intake, drying of tomato has become a subject of extended and varied research works. The present work is focused on the drying behavior of thin-layer tomato and its mathematical modeling in order to optimize the drying processes. The moisture desorption isotherms of raw tomato were determined at four temperature levels namely 45, 50, 60 and 65 °C using the static gravimetric method. The experimental data obtained were modeled by five equations and the (GAB) model was found to be the best-describing these isotherms. The drying kinetics were experimentally investigated at 45, 55 and 65 °C and performed at air velocities of 0.5 and 2 m/s. In order to investigate the effect of the exchange surface on drying time, samples were dried into two different shapes: tomato halves and tomato quarters. The impact of various drying parameters was also studied (temperature, air velocity and air humidity). The drying curves showed only the preheating period and the falling drying rate period. In this study, attention was paid to the modeling of experimental thin-layer drying kinetics. The experimental results were fitted with four different models.

  14. Effects of thin-layer boilover on flame geometry and dynamics in large hydrocarbon pool fires

    Energy Technology Data Exchange (ETDEWEB)

    Ferrero, Fabio; Munoz, Miguel; Arnaldos, Josep [Centre d' Estudis del Risc Tecnologic (CERTEC), Chemical Engineering Department, Universitat Politecnica de Catalunya, Diagonal 647, 08028-Barcelona, Catalonia (Spain)

    2007-03-15

    This work aims to estimate the effects of thin-layer boilover on flame geometry and dynamics. A series of large scale experiments (in pools ranging from 1.5 to 6 m in diameter) were performed using gasoline and diesel as fuel. As expected, only diesel showed evidence of this phenomenon. This article presents a summary of the results obtained for flame height, tilt and pulsation. Flame height increases during water ebullition, though the increase is no longer detectable when wind speed exceeds certain values. Correlations previously presented in the literature to predict flame length and tilt were modified in order to fit the results obtained during thin-layer boilover. However, the influence on flame tilt is not as great and the equations for the stationary period seem suitable for the entire fire. Results of flame pulsation during the stationary period fill the gap in the literature for fires between 1.5 and 6 m and fit previous correlations. On the other hand, during ebullition, the flame pulsates faster, as air entrainment is greater and, as one would expect, this effect decreases with pool size. A new equation for estimating pulsation frequency during boilover is proposed. (author)

  15. Electron beam dosimetry for a thin-layer absorber irradiated by 300-keV electrons

    International Nuclear Information System (INIS)

    Kijima, Toshiyuki; Nakase, Yoshiaki

    1993-01-01

    Depth-dose distributions in thin-layer absorbers were measured for 300-keV electrons from a scanning-type irradiation system, the electrons having penetrated through a Ti-window and an air gap. Irradiations of stacks of cellulose triacetate(CTA) film were carried out using either a conveyor (i.e. dynamic irradiation) or fixed (i.e. static) irradiation. The sample was irradiated using various angles of incidence of electrons, in order to examine the effect of obliqueness of electron incidence at low-energy representative of routine radiation curing of thin polymeric or resin layers. Dynamic irradiation gives broader and shallower depth-dose distributions than static irradiation. Greater obliqueness of incident electrons gives results that can be explained in terms of broader and shallower depth-dose distributions. The back-scattering of incident electrons by a metal(Sn) backing material enhances the absorbed dose in a polymeric layer and changes the overall distribution. It is suggested that any theoretical estimations of the absorbed dose in thin layers irradiated in electron beam curing must be accomplished and supported by experimental data such as that provided by this investigation. (Author)

  16. Estimation of optical constants of a bio-thin layer (onion epidermis), using SPR spectroscopy

    International Nuclear Information System (INIS)

    Rehman, Saif-ur-; Hayashi, Shinji; Sekkat, Zouheir; Mumtaz, Huma; Shaukat, S F

    2014-01-01

    We estimate the optical constants of a biological thin layer (Allium cepa) by surface plasmon resonance (SPR) spectroscopy. For this study, the fresh inner thin epidermis of an onion bulb was used and stacked directly on gold (Au) and silver (Ag) film surfaces in order to identify the shift in SPR mode of each metal film at an operating wavelength of 632.8 nm. The thickness and dielectric constants of the biological thin layer were determined by matching the experimental SPR curves to theoretical ones. The thickness and roughness of bare Au and Ag thin films were also measured by atomic force microscopy (AFM); the results of which are in good agreement with those obtained through experiment. Due to the high surface roughness of the natural onion epidermis layer, AFM could not measure the exact thickness of an onion epidermis. It is estimated that the value of the real part of the dielectric constant of an onion epidermis is between the dielectric constants of water and air. (paper)

  17. Thin layer spectroelectrochemical studies of pertechnetate reduction on the gold electrodes in acidic media

    International Nuclear Information System (INIS)

    Chotkowski, M.; Czerwiński, A.

    2014-01-01

    The electroreduction of pertechnetate ions has been examined in sulfuric acid solutions (0.5 M ÷ 4 M H 2 SO 4 ) using rotating disc electrodes (Au-RDE) and optically transparent thin layer spectroelectrochemical cells (Au/RVC-OTTLE). Soluble Tc(III,IV) species with absorption bands at 502 nm were found to be formed during the reduction of TcO 4 − . The hydrodynamic experiments (Au-RDE) have shown the influence of the acidity of the solution on the activation energy of the electroreduction of the pertechnetate ions to technetium(III,IV) species. The value of the activation energy calculated for limiting current was found to increase from 12.6 ± 1.1 kJ mol −1 for 4 M H 2 SO 4 to 20.1 ± 0.8 kJ mol −1 for 0.5 M H 2 SO 4 . Such an effect suggests an influence of the acid concentration on the structure of obtained products, which are soluble or insoluble Tc species. Thin layer spectroelectrochemical experiments allowed calculation of the redox standard potentials for Tc 2 O 2 3+ /TcO(OH) (aq) system which was found to be equal to 0.255 V vs. Ag,AgCl (KClsat.)

  18. Mercury in a thin layer in HgMn stars: A test of a diffusion model

    International Nuclear Information System (INIS)

    Megessier, C.; Michaud, G.; Weiler, E.J.

    1980-01-01

    Lines of the first three states of ionization of mercury have been observed in μ Leporis and chi Lupi using the Copernicus satellite. Lines of Hg II and Hg III have been observed in α Andromedae. There appears to be an absorption feature at every wavelength where there is expected to be a mercury line. The presence of all three states of ionization is likely in μ Lep and chi Lup. The relative equivalent widths of the lines of the various states of ionization do not depend on the effective temperature of the stars, in contradiction to what is expected if mercury were uniformly distributed in the atmosphere. It is, however, expected if mercury has been concentrated, by diffusion, in a thin layer, where the radiative forces just equal the gravitational forces on mercury. That mercury should be so concentrated is also required by the explanation of the mercury isotope anomaly proposed by Michaud, Reeves, and Charland. The diffusion model for Ap stars predicts in its simplest form the presence of very thin layers. However, any leftover turbulence may increase the depth of these layers without eliminating the element separation

  19. Modelling and experimental validation of thin layer indirect solar drying of mango slices

    Energy Technology Data Exchange (ETDEWEB)

    Dissa, A.O.; Bathiebo, J.; Kam, S.; Koulidiati, J. [Laboratoire de Physique et de Chimie de l' Environnement (LPCE), Unite de Formation et de Recherche en Sciences Exactes et Appliquee (UFR/SEA), Universite de Ouagadougou, Avenue Charles de Gaulle, BP 7021 Kadiogo (Burkina Faso); Savadogo, P.W. [Laboratoire Sol Eau Plante, Institut de l' Environnement et de Recherches Agricoles, 01 BP 476, Ouagadougou (Burkina Faso); Desmorieux, H. [Laboratoire d' Automatisme et de Genie des Procedes (LAGEP), UCBL1-CNRS UMR 5007-CPE Lyon, Bat.308G, 43 bd du 11 Nov. 1918 Villeurbanne, Universite Claude Bernard Lyon1, Lyon (France)

    2009-04-15

    The thin layer solar drying of mango slices of 8 mm thick was simulated and experimented using a solar dryer designed and constructed in laboratory. Under meteorological conditions of harvest period of mangoes, the results showed that 3 'typical days' of drying were necessary to reach the range of preservation water contents. During these 3 days of solar drying, 50%, 40% and 5% of unbound water were eliminated, respectively, at the first, second and the third day. The final water content obtained was about 16 {+-} 1.33% d.b. (13.79% w.b.). This final water content and the corresponding water activity (0.6 {+-} 0.02) were in accordance with previous work. The drying rates with correction for shrinkage and the critical water content were experimentally determined. The critical water content was close to 70% of the initial water content and the drying rates were reduced almost at 6% of their maximum value at night. The thin layer drying model made it possible to simulate suitably the solar drying kinetics of mango slices with a correlation coefficient of r{sup 2} = 0.990. This study thus contributed to the setting of solar drying time of mango and to the establishment of solar drying rates' curves of this fruit. (author)

  20. EFFECT OF MECHANICAL CONDITIONING ON THIN-LAYER DRYING OF ENERGY SORGHUM (Sorghum bicolor (L.) Moench)

    Energy Technology Data Exchange (ETDEWEB)

    Ian J. Bonner; Kevin L. Kenney

    2012-10-01

    Cellulosic energy varieties of Sorghum bicolor (L.) Moench show promise as a bioenergy feedstock, however, high moisture content at the time of harvest results in unacceptable levels of degradation when stored in aerobic conditions. To safely store sorghum biomass for extended periods in baled format, the material must be dried to inhibit microbial growth. One possible solution is allowing the material to dry under natural in-field conditions. This study examines the differences in thin-layer drying rates of intact and conditioned sorghum under laboratory-controlled temperatures and relative humidity levels (20 degrees C and 30 degrees C from 40% to 85% relative humidity), and models experimental data using the Page’s Modified equation. The results demonstrate that conditioning drastically accelerates drying times. Relative humidity had a large impact on the time required to reach a safe storage moisture content for intact material (approximately 200 hours at 30 degrees C and 40% relative humidity and 400 hours at 30 degrees C and 70% relative humidity), but little to no impact on the thin-layer drying times of conditioned material (approximately 50 hours for all humidity levels < 70% at 30 degrees C). The drying equation parameters were influenced by temperature, relative humidity, initial moisture content, and material damage, allowing drying curves to be empirically predicted. The results of this study provide valuable information applicable to the agricultural community and to future research on drying simulation and management of energy sorghum.

  1. Copolymerization preparation of cationic cyclodextrin chiral stationary phases for drug enantioseparation in chromatography

    OpenAIRE

    sprotocols

    2015-01-01

    Authors: Ren-Qi Wang, Teng-Teng Ong, Ke Huang, Weihua Tang & Siu-Choon Ng ### Abstract We described a facile and effective protocol wherein radical copolymerization is employed to covalently bond cationic β-cyclodextrin (β-CD) onto silica particles with extended linkage, resulting in a chiral stationary phase (IMPCSP) that can be used for the enantioseparation of racemic drugs in both high-performance liquid chromatography (HPLC) and supercritical fluid chromatography (SFC). Starting ...

  2. Preparation and evaluation of a hydrophilic interaction and cation-exchange chromatography stationary phase modified with 2-methacryloyloxyethyl phosphorylcholine.

    Science.gov (United States)

    Xiong, Caifeng; Yuan, Jie; Wang, Zhiying; Wang, Siyao; Yuan, Chenchen; Wang, Lili

    2018-04-20

    In this work, 2-methacryloyloxyethyl phosphorylcholine (MPC) was used as a ligand to prepare a novel mixed-mode chromatography (MMC) stationary phase by the thiol-ene click reaction onto silica (MPC-silica). It was found that this MPC-silica showed the retention characteristics of hydrophilic interaction chromatography (HILIC) and weak cation exchange chromatography (WCX) under suitable mobile phase conditions. In detail, acidic and basic hydrophilic compounds and puerarin from pueraria were separated quickly with HILIC mode. Meanwhile, six standard proteins were allowed to reach baseline separation in WCX mode, and protein separation from egg white was also achieved with this mode. In addition, reduced/denatured lysozyme could be refolded with the MPC-silica column. In the meantime, the MPC-silica has been applied for refolding with simultaneous purification of recombinant human Delta-like1-RGD (rhDll1-RGD) expressed in Escherichia coli. The results show that the mass recovery and purity of rhDll1-RGD could reach 63.4% and 97% by one step, respectively. Furthermore, the reporter assay results demonstrated that refolded with simultaneously purified rhDll1-RGD could efficiently activate the signalling pathway in a dose-dependent manner. In general, this MPC-silica has good resolution and selectivity in the separation of polar compounds and protein samples in different high-performance liquid chromatography (HPLC) modes, and it successfully achieved refolding with simultaneous purification of denatured protein. Copyright © 2018 Elsevier B.V. All rights reserved.

  3. Preparation, characterization and application of a reversed phase liquid chromatography/hydrophilic interaction chromatography mixed-mode C18-DTT stationary phase.

    Science.gov (United States)

    Wang, Qing; Long, Yao; Yao, Lin; Xu, Li; Shi, Zhi-Guo; Xu, Lanying

    2016-01-01

    A mixed-mode chromatographic stationary phase, C18-DTT (dithiothreitol) silica (SiO2) was prepared through "thiol-ene" click chemistry. The obtained material was characterized by fourier transform infrared spectroscope, nitrogen adsorption analysis and contact angle analysis. Chromatographic performance of the C18-DTT was systemically evaluated by studying the effect of acetonitrile content, pH, buffer concentration of the mobile phase and column temperature. It was demonstrated that the novel stationary phase possessed reversed phase liquid chromatography (RPLC)/hydrophilic interaction liquid chromatography (HILIC) mixed-mode property. The stop-flow test revealed that C18-DTT exhibited excellent compatibility with 100% aqueous mobile phase. Additionally, the stability and column-to-column reproducibility of the C18-DTT material were satisfactory, with relative standard deviations of retention factor of the tested analytes (verapamil, fenbufen, guanine, tetrandrine and nicotinic acid) in the range of 1.82-3.72% and 0.85-1.93%, respectively. Finally, the application of C18-DTT column was demonstrated in the separation of non-steroidal anti-inflammatory drugs, aromatic carboxylic acids, alkaloids, nucleo-analytes and polycyclic aromatic hydrocarbons. It had great resolving power in the analysis of various compounds in HILIC and RPLC chromatographic conditions and was a promising RPLC/HILIC mixed-mode stationary phase. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Stability indicating high performance thin-layer chromatographic method for simultaneous estimation of pantoprazole sodium and itopride hydrochloride in combined dosage form

    Directory of Open Access Journals (Sweden)

    Deepak Bageshwar

    2011-11-01

    Full Text Available A specific, precise and stability indicating high-performance thin-layer chromatographic method for simultaneous estimation of pantoprazole sodium and itopride hydrochloride in pharmaceutical formulations was developed and validated. The method employed TLC aluminium plates precoated with silica gel 60F254 as the stationary phase. The solvent system consisted of methanol:water:ammonium acetate; 4.0:1.0:0.5 (v/v/v. This system was found to give compact and dense spots for both itopride hydrochloride (Rf value of 0.55±0.02 and pantoprazole sodium (Rf value of 0.85±0.04. Densitometric analysis of both drugs was carried out in the reflectance–absorbance mode at 289 nm. The linear regression analysis data for the calibration plots showed a good linear relationship with R2=0.9988±0.0012 in the concentration range of 100–400 ng for pantoprazole sodium. Also, the linear regression analysis data for the calibration plots showed a good linear relationship with R2=0.9990±0.0008 in the concentration range of 200–1200 ng for itopride hydrochloride. The method was validated for specificity, precision, robustness and recovery. Statistical analysis proves that the method is repeatable and selective for the estimation of both the said drugs. As the method could effectively separate the drug from its degradation products, it can be employed as a stability indicating method. Keywords: Gastroesophageal reflux disease (GERD, Itopride hydrochloride, Pantoprazole sodium, High performance thin layer chromatography (HPTLC, Stability indicating, Forced degradation

  5. Fluorine uptake into the human tooth from a thin layer of F-releasing material

    International Nuclear Information System (INIS)

    Yamamoto, H.; Nomachi, M.; Yasuda, K.; Iwami, Y.; Ebisu, S.; Komatsu, H.; Sakai, T.; Kamiya, T.

    2007-01-01

    Using the proton induced gamma-ray emission (PIGE) method (TIARA, Japan), we have studied fluorine (F) distribution in the human tooth under various conditions. Here, we report F uptake into the human tooth from a thin layer of F-releasing low viscous resin (FLVR). Crowns of human teeth were horizontally cut and the dentin of the cut surface was first covered with four kinds of FLVR (FL-Bond, Reactmer Bond, Xeno Bond, and Protect Liner F; thickness, 50-150 μm) according to the manufacturers' instructions. Non-F-releasing and F-releasing filling resins were also hardened, on the cut surfaces of crowns covered with four kinds of FLVR thin layers. The type of the non-F-releasing filling materials used was LITE FIL IIP: G1-A (FL-Bond and LITE FIL IIP), G2-A (Reactmer Bond and LITE FIL IIP), G3-A (Xeno Bond and LITE FIL IIP), and G4-A (Protect Liner F and LITE FIL IIP). The types of F-releasing filling materials used were G1-B (FL-Bond and Beautifil), G2-B (Reactmer Bond and Reactmer Paste), G3-B (Xeno Bond and Xeno CF Paste), and G4-B (Protect Liner F and Teethmate F-1). Treatment and measurements of specimens were the same as previously reported [H. Yamamoto, M. Nomahci, K. Yasuda, Y. Iwami, S. Ebisu, N. Yamamoto, T. Sakai, T. Kamiya, Nucl. Instr. and Meth. B 210 (2003) 388]. F uptake from specimens following one month of application was estimated from 2-D maps. F penetration was observed in all teeth of G1-A-G4-A groups. The maximum values of F concentration in each tooth and F penetration depth were larger for larger F concentrations in FLVR. FLVR was useful for the F uptake into the tooth, and the F distribution near the thin layer of FLVR depended on the materials used. Between G1-A and G1-B or G4-A and G4-B, the F uptake was significantly different. We were able to obtain fundamental data, which were useful for the analysis of F transportation relating to prevention of caries

  6. Fluorine uptake into the human tooth from a thin layer of F-releasing material

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, H. [Department of Restorative Dentistry and Endodontology, Graduate School of Dentistry, Osaka University, 1-8 Yamadaoka, Suita, Osaka, 565-0871 (Japan)]. E-mail: yhiroko@dent.osaka-u.ac.jp; Nomachi, M. [Graduate School of Science, Osaka University, Toyonaka, Osaka, 560-0043 (Japan); Yasuda, K. [Wakasa Wan Energy Research Center, Tsuruga, Fukui, 914-0192 (Japan); Iwami, Y. [Department of Restorative Dentistry and Endodontology, Graduate School of Dentistry, Osaka University, 1-8 Yamadaoka, Suita, Osaka, 565-0871 (Japan); Ebisu, S. [Department of Restorative Dentistry and Endodontology, Graduate School of Dentistry, Osaka University, 1-8 Yamadaoka, Suita, Osaka, 565-0871 (Japan); Komatsu, H. [Graduate School of Dental Medicine, Hokkaido University, Sapporo, Hokkaido, 060-8585 (Japan); Sakai, T. [Advanced Radiation Technology Center, JAERI, Takasaki, Gunma, 370-1292 (Japan); Kamiya, T. [Advanced Radiation Technology Center, JAERI, Takasaki, Gunma, 370-1292 (Japan)

    2007-07-15

    Using the proton induced gamma-ray emission (PIGE) method (TIARA, Japan), we have studied fluorine (F) distribution in the human tooth under various conditions. Here, we report F uptake into the human tooth from a thin layer of F-releasing low viscous resin (FLVR). Crowns of human teeth were horizontally cut and the dentin of the cut surface was first covered with four kinds of FLVR (FL-Bond, Reactmer Bond, Xeno Bond, and Protect Liner F; thickness, 50-150 {mu}m) according to the manufacturers' instructions. Non-F-releasing and F-releasing filling resins were also hardened, on the cut surfaces of crowns covered with four kinds of FLVR thin layers. The type of the non-F-releasing filling materials used was LITE FIL IIP: G1-A (FL-Bond and LITE FIL IIP), G2-A (Reactmer Bond and LITE FIL IIP), G3-A (Xeno Bond and LITE FIL IIP), and G4-A (Protect Liner F and LITE FIL IIP). The types of F-releasing filling materials used were G1-B (FL-Bond and Beautifil), G2-B (Reactmer Bond and Reactmer Paste), G3-B (Xeno Bond and Xeno CF Paste), and G4-B (Protect Liner F and Teethmate F-1). Treatment and measurements of specimens were the same as previously reported [H. Yamamoto, M. Nomahci, K. Yasuda, Y. Iwami, S. Ebisu, N. Yamamoto, T. Sakai, T. Kamiya, Nucl. Instr. and Meth. B 210 (2003) 388]. F uptake from specimens following one month of application was estimated from 2-D maps. F penetration was observed in all teeth of G1-A-G4-A groups. The maximum values of F concentration in each tooth and F penetration depth were larger for larger F concentrations in FLVR. FLVR was useful for the F uptake into the tooth, and the F distribution near the thin layer of FLVR depended on the materials used. Between G1-A and G1-B or G4-A and G4-B, the F uptake was significantly different. We were able to obtain fundamental data, which were useful for the analysis of F transportation relating to prevention of caries.

  7. Determination of radiochemical yield of 99mTc radiopharmaceutical preparations using gamma counter and linear radiochromatography scanner

    International Nuclear Information System (INIS)

    Martins, Patricia de A.; Moura, Rebeca G.; Shiki, Andressa M.; Fukumori, Neuza T.O.; Matsuda, Margareth M.N.

    2013-01-01

    The radiochemical purity (RCP) evaluation is a prerequisite for radiopharmaceuticals before the administration in patients. RCP is defined as the proportion of the total radioactivity in the product that is present in the specified chemical form. The most widely used techniques for RCP determination in radiopharmaceutical preparations are thin layer chromatography (TLC-Al), instant thin layer chromatography (ITLC-SG) and paper chromatography (PC). These techniques combined with radioactivity detection are one of the most important tools in the RCP of the radiopharmaceutical compounds. Several methods are used for the determination of the spatial distribution of radioactivity on the strips. The aim of this study was to compare two methods for radioactivity measurement in the determination of RCP in 99m Tc radiopharmaceuticals using gamma counter and linear radiochromatography scanner. Lyophilized radiopharmaceuticals were labeled with 99m Tc. The analysis was carried out using TLC-Al and high performance thin layer chromatography (HPTLC-Cellulose) sheets, ITLC-SG and 3MM Whatman PC. The radioactivity distribution was determined by counting each strip during 1 minute in a radiochromatography TLC scanner. For comparison, the strips were cut into small pieces and each one was separately measured in a gamma-counter during 0.20 minutes in 70-210 KeV 99m Tc window. USP 36 and FDA specify that not less than 90% of the total radioactivity must be in the spot corresponding to 99m Tc labeled compound. In conclusion, the procedure for RCP determination of ALBUMINA-TEC, DEX500-TEC, ECD-TEC, MACRO-TEC and MIBI-TEC can be faster using radiochromatography. (author)

  8. Determination of radiochemical yield of {sup 99m}Tc radiopharmaceutical preparations using gamma counter and linear radiochromatography scanner

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Patricia de A.; Moura, Rebeca G.; Shiki, Andressa M.; Fukumori, Neuza T.O.; Matsuda, Margareth M.N., E-mail: patyosborne@yahoo.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2013-07-01

    The radiochemical purity (RCP) evaluation is a prerequisite for radiopharmaceuticals before the administration in patients. RCP is defined as the proportion of the total radioactivity in the product that is present in the specified chemical form. The most widely used techniques for RCP determination in radiopharmaceutical preparations are thin layer chromatography (TLC-Al), instant thin layer chromatography (ITLC-SG) and paper chromatography (PC). These techniques combined with radioactivity detection are one of the most important tools in the RCP of the radiopharmaceutical compounds. Several methods are used for the determination of the spatial distribution of radioactivity on the strips. The aim of this study was to compare two methods for radioactivity measurement in the determination of RCP in {sup 99m}Tc radiopharmaceuticals using gamma counter and linear radiochromatography scanner. Lyophilized radiopharmaceuticals were labeled with {sup 99m}Tc. The analysis was carried out using TLC-Al and high performance thin layer chromatography (HPTLC-Cellulose) sheets, ITLC-SG and 3MM Whatman PC. The radioactivity distribution was determined by counting each strip during 1 minute in a radiochromatography TLC scanner. For comparison, the strips were cut into small pieces and each one was separately measured in a gamma-counter during 0.20 minutes in 70-210 KeV {sup 99m}Tc window. USP 36 and FDA specify that not less than 90% of the total radioactivity must be in the spot corresponding to {sup 99m}Tc labeled compound. In conclusion, the procedure for RCP determination of ALBUMINA-TEC, DEX500-TEC, ECD-TEC, MACRO-TEC and MIBI-TEC can be faster using radiochromatography. (author)

  9. Propagation of edge waves in a thinly layered laminated medium with stress couples under initial stresses

    Directory of Open Access Journals (Sweden)

    Pijush Pal Roy

    1987-01-01

    Full Text Available The propagation of edge waves in a thinly layered laminated medium with stress couples under initial stresses is examined. Based upon an approximate representation of a laminated medium by an equivalent anisotropic continuum with average initial and couple stresses, an explicit form of frequency equation is obtained to derive the phase velocity of edge waves. Edge waves exist under certain conditions. The inclusion of couple stresses increases the velocity of wave propagation. For a specific compression, the presence of couple stresses increases the velocity of wave propagation with the increase of wave number, whereas the reverse is the case when there is no couple stress. Numerical computation is performed with graphical representations. Several special cases are also examined.

  10. Towards single photon generation using NV centers in diamond coupled to thin layer optical waveguides

    International Nuclear Information System (INIS)

    Toshiyuki Tashima

    2014-01-01

    Single photon emitters like the nitrogen-vacancy (NV) center in diamond are important for quantum communication such as quantum cryptography and quantum metrology. In this context, e.g. tapered optical nano-fibers are a promising approach as they allow efficient coupling of single photons into a single spatial mode. Yet, integration of such fibers in a compact integrated quantum circuit is demanding. Here we propose a NV defect center in diamond as a single photon emitter coupled to a thin layer photonic waveguide. The benefit is to allow smaller size devices while having a similar strong evanescent field like tapered nano-optical fibers. We present numerical simulations and fabrication steps of such structures. (author)

  11. Thin layer activation : on-line monitoring of metal loss in process plant

    International Nuclear Information System (INIS)

    Boulton, L.H.; Wallace, G.

    1993-01-01

    Corrosion, erosion and wear of metals is a common cause of failure in some process plant and equipment. Monitoring of these destructive effects has been done for many years to help plant engineers minimise the damage, in order to avoid unexpected failures and unscheduled shutdowns. Traditional methods of monitoring, such as standard NDT techniques, inform the engineer of what has happened, providing data such as culmulative loss of wall thickness. The modern approach to monitoring however, is to employ a technique which gives both current loss rates as well as integrated losses. Thin Layer Activation (TLA) provides on-line monitoring of corrosion, erosion and wear of metals, to a high degree of accuracy. It also gives cumulative information which can be backed up with weight-loss results if required. Thus current rather than historical loss rates are measured before any significant loss of metal has occurred. (author). 14 refs., 2 figs

  12. Stacking and electric field effects in atomically thin layers of GaN

    International Nuclear Information System (INIS)

    Xu, Dongwei; He, Haiying; Pandey, Ravindra; Karna, Shashi P

    2013-01-01

    Atomically thin layers of nitrides are a subject of interest due to their novel applications. In this paper, we focus on GaN multilayers, investigating their stability and the effects of stacking and electric fields on their electronic properties in the framework of density functional theory. Both bilayers and trilayers prefer a planar configuration rather than a buckled bulk-like configuration. The application of an external perpendicular electric field induces distinct stacking-dependent features in the electronic properties of nitride multilayers: the band gap of a monolayer does not change whereas that of a trilayer is significantly reduced. Such a stacking-dependent tunability of the band gap in the presence of an applied field suggests that multilayer GaN is a good candidate material for next generation devices at the nanoscale. (paper)

  13. On-line monitoring of wear and/or corrosion processes by thin layer activation technique

    International Nuclear Information System (INIS)

    Alexandreanu, B.; Popa-Simil, L.; Voiculescu, D.; Racolta, P.M.

    1995-01-01

    The Thin Layer Activation (TLA) principle consists in creating a radioactive layer by ion beam irradiation of a machine part subjected to wear. The method is based on the determination of the increasing radioactivity in the lubricant due to suspended wear particles and has a sensitivity threshold of about 40 μ g / cm 2 . The most used radioactive markers are 56 Co, 57 Co, 65 Zn, 51 Cr, 48 V, 124 Sb. In this paper, we have chosen to present an on-line wear level determination experiment performed for a thermal engine. The study of possible influence of a SR3 added lubricant upon the wear level of a Dacia 1410 car engine is presented, illustrating the on-line TLA based monitoring of wear for industrial uses. The examples presented outline the advantages of this method over the conventional one, like the fast response and the high sensitivity, while no dismantling of the engine is implied. (author)

  14. Electronic structure evolution in doping of fullerene (C{sub 60}) by ultra-thin layer molybdenum trioxide

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Chenggong; Wang, Congcong; Kauppi, John [Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627 (United States); Liu, Xiaoliang [Institute for Super-microstructure and Ultrafast Process in Advanced Materials (ISUPAM), Central South University, Changsha, Hunan 410083 (China); Gao, Yongli, E-mail: ygao@pas.rochester.edu [Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627 (United States); Institute for Super-microstructure and Ultrafast Process in Advanced Materials (ISUPAM), Central South University, Changsha, Hunan 410083 (China)

    2015-08-28

    Ultra-thin layer molybdenum oxide doping of fullerene has been investigated using ultraviolet photoemission spectroscopy (UPS) and X-ray photoemission spectroscopy (XPS). The highest occupied molecular orbital (HOMO) can be observed directly with UPS. It is observed that the Fermi level position in fullerene is modified by ultra-thin-layer molybdenum oxide doping, and the HOMO onset is shifted to less than 1.3 eV below the Fermi level. The XPS results indicate that charge transfer was observed from the C{sub 60} to MoO{sub x} and Mo{sup 6+} oxides is the basis as hole dopants.

  15. Thin-layer boilover in diesel-oil fires: Determining the increase of thermal hazards and safety distances

    International Nuclear Information System (INIS)

    Ferrero, Fabio; Munoz, Miguel; Arnaldos, Josep

    2007-01-01

    A study of the effects of thin-layer boilover on large hydrocarbon fires was carried out. In the experiments, diesel-oil was burned in pools with diameters ranging from 1.5 to 6 m. Previous models used to predict emissive power during the stationary state were analysed and successively modified in order to accurately predict thermal hazard during the water ebullition phase. It was discovered that the increase in emissive power during thin-layer boilover is greater when the pool diameter is smaller. Furthermore, the required increases in safety distances in the case of accidents involving this dangerous phenomenon are provided

  16. Experimental study of soil-structure interaction for proving the three dimensional thin layered element method

    International Nuclear Information System (INIS)

    Kuwabara, Y.; Ogiwara, Y.; Suzuki, T.; Tsuchiya, H.; Nakayama, M.

    1981-01-01

    It is generally recognized that the earthquake response of a structure can be significantly affected by the dynamic interaction between the structure and the surrounding soil. Dynamic soil-structure interaction effects are usually analyzed by using a lumped mass model or a finite element model. In the lumped mass model, the soil is represented by springs and dashpots based on the half-space elastic theory. Each model has its advantages and limitations. The Three Dimensional Thin Layered Element Theory has been developed by Dr. Hiroshi Tajimi based on the combined results of the abovementioned lumped mass model and finite element model. The main characteristic of this theory is that, in consideration and can be applied in the analysis of many problems in soil-structure interaction, such as those involving radiation damping, embedded structures, and multi-layered soil deposits. This paper describes test results on a small scale model used to prove the validity of the computer program based on the Thin Layered Element Theory. As a numerical example, the response analysis of a PWR nuclear power plant is carried out using this program. The vibration test model is simplified and the scale is 1/750 for line. The soil layer of the model is made of congealed gelatine. The test soil layer is 80 cm long, 35 cm wide and 10 cm thick. The super structure is a one mass model made of metal sheet spring and solid mass metal. As fixed inputs, sinusoidal waves (10, 20 gal level) are used. The displacements of the top and base of the super structure, and the accelerations and the displacements of the shaking table are measured. The main parameter of the test is the shear wave velocity of the soil layer. (orig./RW)

  17. Evidence for moving of threading dislocations during the VPE growth in GaN thin layers

    Energy Technology Data Exchange (ETDEWEB)

    Kuwano, Noriyuki [Art, Science and Technology Center for Cooperative Research, Kyushu University, Kasuga, Fukuoka 816-8580 (Japan); Department of Applied Science for Electronics and Materials, Kyushu University, Kasuga, Fukuoka 816-8580 (Japan); Miyake, Hideto; Hiramatsu, Kazumasa [Department of Electrical and Electronic Engineering, Mie University, Tsu, Mie 514-8507 (Japan); Amano, Hiroshi [Graduate School of Engineering, Akasaki Research Center, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8603 (Japan); Akasaki, Isamu [Faculty of Science and Technology, Meijo University, 1-501 Shiogamaguchi, Tempaku, Nagoya 468-8502 (Japan)

    2011-05-15

    Cross-sectional transmission electron microscope (TEM) observation was performed in detail to analyze the morphology of threading dislocations (TDs) in GaN thin layers with various thicknesses. The GaN layers were overgrown on an Al{sub 0.28}Ga{sub 0.72}N layer by the metal-organic vapor-phase epitaxy (MOVPE) method. In a GaN layer about 50 nm in thickness, TDs running up in the AlGaN layer pass into the GaN layer and most of them reach the top surface without bending. In thicker GaN layers, on the other hand, many of TDs form a hairpin-configuration on or above the interface of GaN and AlGaN to be annihilated. This difference in morphology of TDs indicates that the TDs have moved down inside the GaN layer. Since the formation of hairpins is attributed to a stress-relief, there should be an extra half-plane between the paired TDs. Therefore, the movement of TDs should be of ''climb motion''. Another example of possible TD movement inside a GaN layer is also described. It is emphasized that the possibility of TD-movements inside the thin film crystal during the growth should be taken into account in analysis of thin-layer growth through the behavior of TDs (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  18. The uranium valence in the Cs-U-O system: crystal structures and thin layers contribution to the physico-chemical study of grain boundaries in irradiated fuel

    International Nuclear Information System (INIS)

    Van Den Berghe, S.

    2002-01-01

    The document is an abstract of a PhD thesis. The PhD thesis investigates the way in which cesium, through its effect on oxygen, modifies the uranium environment and in consequence the valence state of the uranium atom itself. To this end, the crystallographic structure and local uranium environment of several uranium uranates has been determined by Rietveld refinement of neutron and X-ray diffraction data. Thin layers of stoichiometric uranium dioxide were prepared using sputter deposition techniques and used to model interactions on the grain boundaries. They were covered with cesium and exposed to controlled amounts of oxygen, while the uranium valence state was monitored with Ultraviolet Photoelectron Spectroscopy and XPS

  19. Preparative separation of flavonoids from the medicinal plant Davilla elliptica St. Hill. by high-speed counter-current chromatography

    OpenAIRE

    Rinaldo Daniel; Silva Marcelo Aparecido; Rodrigues Clenilson Martins; Calvo Tamara Regina; Sannomiya Miriam; Santos Lourdes Campaner dos; Vilegas Wagner; Kushima Hélio; Hiruma-Lima Clélia Akiko; Brito Alba Regina Monteiro de Souza

    2006-01-01

    High-speed counter-current chromatography (HSCCC) is a major tool for the fast separation of natural products from plants. It was used for the preparative isolation of the flavonoid monoglucosides present in the aerial parts of the Davilla elliptica St. Hill. (Dilleniaceae). This species is used in Brazilian folk medicine for the treatment of gastric disorders. The optimum solvent system used was composed of a mixture of ethyl acetate-n-propanol-water (140:8:80, v/v/v) and led to a successful...

  20. Preparation of [3beta-3H] labeled bile acids and bile alcohols

    International Nuclear Information System (INIS)

    Dayal, B.; Baga, E.; Tint, G.S.; Shefer, S.; Salen, G.

    1979-01-01

    [3beta-3H]-bile acids and bile alcohols may be useful for metabolic studies in man and animals because the 3-position is invulnerable to bacterial attack. A number of tritium labeled bile acids and bile alcohols were prepared by selective oxidation of the hydroxyl group at carbon-3 followed by reduction with NaBT4. In each case, the bile acids and bile alcohols epimeric at carbon-3 were resolved by analytical and preparative thin-layer chromatography and characterized by gas liquid chromatography. The average yield was 60 to 65% and specific activities of the final products were in the range of 7.4 x 10 7 dpm/mg

  1. Effects of Na incorporation and plasma treatment on Bi{sub 2}S{sub 3} ultra-thin layers

    Energy Technology Data Exchange (ETDEWEB)

    Moreno-Garcia, H., E-mail: hamog@ier.unam.mx [Laboratorio de Espectroscopía, Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Apartado Postal 48-3, 62210 Cuernavaca, Morelos (Mexico); Messina, S. [Universidad Autónoma de Nayarit, Ciudad de la Cultura “Amado Nervo” S/N, C.P. 63155 Tepic, Nayarit (Mexico); Calixto-Rodriguez, M. [Universidad Tecnológica Emiliano Zapata del Estado de Morelos, Av. Universidad Tecnológica No. 1, C.P. 62760 Emiliano Zapata, Morelos (Mexico); Martínez, H. [Laboratorio de Espectroscopía, Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Apartado Postal 48-3, 62210 Cuernavaca, Morelos (Mexico)

    2016-04-01

    As-deposited bismuth sulfide thin films prepared by means of a chemical bath deposition were treated with argon AC plasma. In this paper, we present the results on the physical modifications which were observed when a pre-treatment, containing a solution of 1 M sodium hydroxide, was applied to the glass substrates before depositing the bismuth sulfide. The bismuth sulfide thin films were characterized by X-ray diffraction, energy dispersive X-ray spectroscopy, scanning electron microscopy, atomic force microscopy, UV–VIS, and electrical measurements. The XRD analysis demonstrated an enhancement in the crystalline properties, as well as an increment in the crystal size. The energy band gap value was calculated as 1.60 eV. Changes in photoconductivity (σ{sub p}) values were also observed due to the pre-treatment in NaOH. A value of σ{sub p} = 6.2 × 10{sup −6} (Ω cm){sup −1} was found for samples grown on substrates without pre-treatment, and a value of σ{sub p} = 0.28 (Ω cm){sup −1} for samples grown on substrates with pre-treatment. Such σ{sub p} values are optimal for the improvement of solar cells based on Bi{sub 2}S{sub 3} thin films as absorber material. - Highlights: • We report our findings about Na incorporation and plasma treatment on Bi{sub 2}S{sub 3} thin layers. • The Na pre-treatment improves the structural and electrical properties of Bi{sub 2}S{sub 3} films. • The E{sub g} value was 1.60 eV for films with pre-treatment with NaOH and treatment in Ar plasma.

  2. An efficient preparative procedure for main flavonoids from the peel of Trichosanthes kirilowii Maxim. using polyamide resin followed by semi-preparative high performance liquid chromatography.

    Science.gov (United States)

    Li, Aifeng; Sun, Ailing; Liu, Renmin; Zhang, Yongqing; Cui, Jichun

    2014-08-15

    In this study, a simple and efficient preparative procedure was developed for preparation of seven flavonoids from the peel of Trichosanthes kirilowii Maxim. using polyamide resin followed by semi-preparative high performance liquid chromatography (SPHPLC). First, the ethyl acetate fraction from the peel of T. kirilowii Maxim. obtained "prefractionation" using polyamide resin, which yielded two subfractions. And then the two subfractions were isolated by SPHPLC with an isocratic elution of methanol-water. Finally, seven known flavonoids were purified from 35 g of ethyl acetate extract including quercetin-3-O-[α-l-rhamnose (1→2)-β-d-glucopyranosyl]-5-O-β-d-glucopyranoside (19 mg), quercetin-3-O-rutinoside (24 mg), apigenin-7-O-β-d-glucopyranoside (10mg), diosmetin-7-O-β-d-glucopyranoside (45 mg), luteolin (21 mg), apigenin (15 mg), and diosmetin (56 mg). The purities of the compounds were determined by HPLC and the chemical structures were confirmed by UV and NMR analysis. In the present study, a simple, effective, and rapid procedure was established for preparative separation of multiple components from the peel of T. kirilowii Maxim. Furthermore, it was scalable and economical, so it was a promising basis for large-scale preparation of flavonoids from other plant extracts. Copyright © 2014. Published by Elsevier B.V.

  3. Use of laminar chromatographic methods for determination of separation conditions in column extraction chromatography

    International Nuclear Information System (INIS)

    Ghersini, G.; Cerrai, E.

    1978-01-01

    Possibilities of using laminar chromatographic methods (paper and thin-layer chromatography) to determine optimal separation conditions in column extraction chromatography are analysed. Most of the given laminar methods are presented as Rf-spectra, i.e. as dependences of Rf found experimentally on eluating solution component concentration. Interrelation between Rf and distribution coefficients of corresponding liquid extraction systems and retention volumes of chromatographic columns is considered. Literature data on extraction paper and thin-layer chromatography of elements with various immovable phases are presented

  4. A simple liquid extraction protocol for overcoming the ion suppression of triacylglycerols by phospholipids in liquid chromatography mass spectrometry studies.

    Science.gov (United States)

    Araujo, Pedro; Tilahun, Ephrem; Breivik, Joar Fjørtoft; Abdulkader, Bashir M; Frøyland, Livar; Zeng, Yingxu

    2016-02-01

    It is well-known that triacylglycerol (TAG) ions are suppressed by phospholipid (PL) ions in regiospecific analysis of TAG by mass spectrometry (MS). Hence, it is essential to remove the PL during sample preparation prior to MS analysis. The present article proposes a cost-effective liquid-liquid extraction (LLE) method to remove PL from TAG in different kinds of biological samples by using methanol, hexane and water. High performance thin layer chromatography confirmed the lack of PL in krill oil and salmon liver samples, submitted to the proposed LLE protocol, and liquid chromatography tandem MS confirmed that the identified TAG ions were highly enhanced after implementing the LLE procedure. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Preparative Separation of Six Rhynchophylla Alkaloids from Uncaria macrophylla Wall by pH-Zone Refining Counter-Current Chromatography

    Directory of Open Access Journals (Sweden)

    Qinghai Zhang

    2013-12-01

    Full Text Available pH-Zone refining counter-current chromatography was successfully applied to the preparative isolation and purification of six alkaloids from the ethanol extracts of Uncaria macrophylla Wall. Because of the low content of alkaloids (about 0.2%, w/w in U. macrophylla Wall, the target compounds were enriched by pH-zone refining counter-current chromatography using a two-phase solvent system composed of petroleum ether–ethyl acetate–isopropanol–water (2:6:3:9, v/v, adding 10 mM triethylamine in organic stationary phase and 5 mM hydrochloric acid in aqueous mobile phase. Then pH-zone refining counter-current chromatography using the other two-phase solvent system was used for final purification. Six target compounds were finally isolated and purified by following two-phase solvent system composed of methyl tert-butyl ether (MTBE–acetonitrile–water (4:0.5:5, v/v, adding triethylamine (TEA (10 mM to the organic phase and HCl (5 mM to aqueous mobile phase. The separation of 2.8 g enriched total alkaloids yielded 36 mg hirsutine, 48 mg hirsuteine, 82 mg uncarine C, 73 mg uncarine E, 163 mg rhynchophylline, and 149 mg corynoxeine, all with purities above 96% as verified by HPLC Their structures were identified by electrospray ionization-mass spectrometry (ESI-MS and 1H-NMR spectroscopy.

  6. Preparation and evaluation of surface-bonded tricationic ionic liquid silica as stationary phases for high-performance liquid chromatography.

    Science.gov (United States)

    Qiao, Lizhen; Shi, Xianzhe; Lu, Xin; Xu, Guowang

    2015-05-29

    Two tricationic ionic liquids were prepared and then bonded onto the surface of supporting silica materials through "thiol-ene" click chemistry as new stationary phases for high-performance liquid chromatography. The obtained columns of tricationic ionic liquids were evaluated respectively in the reversed-phase liquid chromatography (RPLC) mode and hydrophilic interaction liquid chromatography (HILIC) mode, and possess ideal column efficiency of 80,000 plates/m in the RPLC mode with naphthalene as the test solute. The tricationic ionic liquid stationary phases exhibit good hydrophobic and shape selectivity to hydrophobic compounds, and RPLC retention behavior with multiple interactions. In the HILIC mode, the retention and selectivity were evaluated through the efficient separation of nucleosides and bases as well as flavonoids, and the typical HILIC retention behavior was demonstrated by investigating retention changes of hydrophilic solutes with water volume fraction in mobile phase. The results show that the tricationic ionic liquid columns possess great prospect for applications in analysis of hydrophobic and hydrophilic samples. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Preparative separation of six rhynchophylla alkaloids from Uncaria macrophylla wall by pH-zone refining counter-current chromatography.

    Science.gov (United States)

    Zhang, Qinghai; Lin, Changhu; Duan, Wenjuan; Wang, Xiao; Luo, Aiqin

    2013-12-12

    pH-Zone refining counter-current chromatography was successfully applied to the preparative isolation and purification of six alkaloids from the ethanol extracts of Uncaria macrophylla Wall. Because of the low content of alkaloids (about 0.2%, w/w) in U. macrophylla Wall, the target compounds were enriched by pH-zone refining counter-current chromatography using a two-phase solvent system composed of petroleum ether-ethyl acetate-isopropanol-water (2:6:3:9, v/v), adding 10 mM triethylamine in organic stationary phase and 5 mM hydrochloric acid in aqueous mobile phase. Then pH-zone refining counter-current chromatography using the other two-phase solvent system was used for final purification. Six target compounds were finally isolated and purified by following two-phase solvent system composed of methyl tert-butyl ether (MTBE)-acetonitrile-water (4:0.5:5, v/v), adding triethylamine (TEA) (10 mM) to the organic phase and HCl (5 mM) to aqueous mobile phase. The separation of 2.8 g enriched total alkaloids yielded 36 mg hirsutine, 48 mg hirsuteine, 82 mg uncarine C, 73 mg uncarine E, 163 mg rhynchophylline, and 149 mg corynoxeine, all with purities above 96% as verified by HPLC Their structures were identified by electrospray ionization-mass spectrometry (ESI-MS) and 1H-NMR spectroscopy.

  8. Studies concerning the preparation of the 153Sm complex with EDTMP (ethylenediaminetetra methylenephosphonic acid) and other 153Sm complexes with other phosphonates, at room temperature

    International Nuclear Information System (INIS)

    Gasiglia, Haroldo Taurian

    2000-01-01

    This work presents a study on the preparation of the complexes 1 53S m - EDTMP, 153 Sm - HEDP, 153 Sm - NTMP, 153 Sm - DTPMP and 153 Sm - HDTMP at room temperature. The preparation of the complex 153 Sm - HDTMP, under heating (70 - 72 deg C), was also studied. Several factors affecting the 153 Sm - EDTMP complexing yields were studied, due to its importance for use in Nuclear Medicine. These factors were: the molar ratio [ligand] / [metal], the ligand concentration and the incubation time of the mixture ligand-metal. The preparation of this complex, in low molar ratios, was also investigated. A study of the 153 Sm - EDTMP concerning the 'in vitro' stability, when this complex was prepared in low radioactive concentrations was performed. A study on the temperature influence on its degradation, when this complex was obtained in higher radioactive concentrations, was also performed. The preparation of the complexes 153 Sm - HEDP, 153 Sm - NTMP, 153 Sm - DTPMP and 153 Sm - HDTMP was investigated by preparing the complexes in two situations: high molar ratio and ligand concentration and low molar ratio and ligand concentration. The 'in vitro' stability of each complex, obtained in low radioactive concentration was studied. In the specific case of the complex 153 Sm - HDTMP, its biological distribution in mice was performed. All the complexes were investigated by high performance liquid chromatography (HPLC) and its complexing yields were determined by other three chromatographic processes: ionic exchange, thin layer chromatography (TLC - SG) and paper chromatography. The chromatographic processes were performed by association with specific radiochemical techniques. This work also presents a comparative study on the chromatograms obtained by thin layer chromatography (TLC - SG) and paper chromatography, when evaluated by the technique of cutting the strips into pieces and the chromatograms performed directly on a radiochromatography. The shape of the chromatograms and R

  9. Hydroxylapatite chromatography.

    Science.gov (United States)

    Broadhurst, A V

    2001-05-01

    Hydroxylapatite (also called hydroxyapatite), a form of calcium phosphate, can be used as a matrix for the chromatography of both proteins and nucleic acids. Protocols are provided for both standard low-pressure chromatography of a protein mixture using a hydroxylapatite column prepared in the laboratory, and an HPLC method, applicable to proteins and nucleic acids, that uses a commercially available column. Alternate protocols describe column chromatography using a step gradient or batch binding and step-gradient elution.

  10. Ligand exchange chromatography for analysis and preparative separation of tritium-labelled amino acids

    International Nuclear Information System (INIS)

    Zolotarev, Yu.A.; Zaitsev, D.A.; Penkina, V.I.; Dostavalov, I.N.; Myasoedov, N.F.

    1988-01-01

    Racemic tritium-labelled amino acids were separated into optical isomers by chromatography on a chiral polyacrylamide sorbent filled with copper ions. The polyacrylamide sorbent is synthesized by Mannich's reaction through the action of formaldehyde and L-phenylalanine upon polyacrylamide Biogel P-4 in an alkali phosphate buffer. Tritium-labelled amino acids are eluted by a weak alkali solution of ammonium carbonate. Data are presented on the ligand exchange chromatography of amino acids depending on the degree to which the sorbent is filled with copper ions and on the eluent concentration. Amino acids are isolated from the eluent on short columns filled with sulfonated cation exchanger in the H + form. HPLC on modified silica gel sorbents is also used for the analysis of tritium-labelled optically active amino acids. Amino acids are eluted by a weakly acidic water-methanol solution containing ammonium acetate. UV and scintillation flow type detectors are used. (author) 7 refs.; 8 figs

  11. Preparation of factor VII concentrate using CNBr-activated Sepharose 4B immunoaffinity chromatography

    OpenAIRE

    Mousavi Hosseini, Kamran; Nasiri, Saleh

    2015-01-01

    Background: Factor VII concentrates are used in patients with congenital or acquired factor VII deficiency or treatment of hemophilia patients with inhibitors. In this research, immunoaffinity chromatography was used to purify factor VII from prothrombin complex (Prothrombin- Proconvertin-Stuart Factor-Antihemophilic Factor B or PPSB) which contains coagulation factors II, VII, IX and X. The aim of this study was to improve purity, safety and tolerability as a highly purified factor VII conce...

  12. Separation of the potential G-quadruplex ligands from the butanol extract of Zanthoxylum ailanthoides Sieb. & Zucc. by countercurrent chromatography and preparative high performance liquid chromatography.

    Science.gov (United States)

    Han, Tian; Cao, Xueli; Xu, Jing; Pei, Hairun; Zhang, Hong; Tang, Yalin

    2017-07-21

    G-quadruplex DNA structure is considered to be a very attractive target for antitumor drug design due to its unique role in maintaining telomerase activities. Therefore, discovering ligands with high stability of G-quadruplex structure is of great interest. In this paper, pH-zone refining counter current chromatography (CCC) and preparative high performance liquid chromatography (HPLC) were employed for the separation of potent G-quadruplex ligands from the n-butanol fraction of the crude extract of Zanthoxylum ailanthoides, which is a traditional Chinese medicine recently found to display high inhibitory activity against several human cancer cells. The 75% aqueous ethanol extract of the stem bark of Z. ailanthoides and its fractions with petroleum ether, ethyl acetate and n-butanol displayed almost the same G-quadruplex stabilization ability. Here, pH-zone refining CCC was used for the separation of the alkaloids from the n-butanol fraction by a seldom used solvent system composed of dichloromethane-methanol-water (4:1:2.5) with 10mM TEA in the organic stationary phase as retainer and 10mM HCl in the aqueous mobile phase as eluter. Compounds I, II and III were obtained, with purity greater than 95%, in the quantities of 31.2, 94.0, and 26.4mg respectively from 300mg of lipophilic fraction within 80min, which were identified as three tetrahydroprotoberberines isolated for the first time in this plant. In addition, a phenylpropanoid glycoside compound IV (Syringin), an isoquinoline (Magnoflorine, V), and two lignin isomers (+)-lyoniresiol-3α-O-β-d-glucopyranoside (VI) and (-)-lyoniresinol -3α-O-β-D -glucopyranoside (VII) were isolated by traditional CCC together with preparative HPLC. Compounds IV, V, VI and VII were obtained, with purity greater than 95%, in the quantities of 4.0, 13.2, 6.7, and 6.5mg respectively from 960mg of hydrophilic fraction. Among the seven isolated compounds, tetrahydroprotoberberine I, II and III were found to display remarkable

  13. Rapid preparative separation of monoclonal antibody charge variants using laterally-fed membrane chromatography.

    Science.gov (United States)

    Sadavarte, Rahul; Madadkar, Pedram; Filipe, Carlos Dm; Ghosh, Raja

    2018-01-15

    Monoclonal antibodies undergo various forms of chemical transformation which have been shown to cause loss in efficacy and alteration in pharmacokinetic properties of these molecules. Such modified antibody molecules are known as variants. They also display physical properties such as charge that are different from intact antibody molecules. However, the difference in charge is very subtle and separation based on it is quite challenging. Charge variants are usually separated using ion-exchange column chromatography or isoelectric focusing. In this paper, we report a rapid and scalable method for fractionating monoclonal antibody charge variants, based on the use of cation exchange laterally-fed membrane chromatography (LFMC). Starting with a sample of monoclonal antibody hIgG1-CD4, three well-resolved fractions were obtained using either pH or salt gradient. These fractions were identified as acidic, neutral and basic variants. Each of these fractions contained intact heavy and light chains and so antibody fragmentation had no role in variant generation. The separation was comparable to that using column chromatography but was an order of magnitude faster. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. A chip-type thin-layer electrochemical cell coupled with capillary electrophoresis for online separation of electrode reaction products

    Energy Technology Data Exchange (ETDEWEB)

    He, Jian-Bo, E-mail: jbhe@hfut.edu.cn; Cui, Ting; Zhang, Wen-Wen; Deng, Ning

    2013-07-05

    Graphical abstract: -- Highlights: •A new coupling of thin-layer electrolysis with capillary electrophoresis (CE). •Rapid electrolysis, direct sampling followed by online CE separation. •At least 13 products of quercetin oxidation were separated. •Thermodynamic and kinetic parameters were determined from CE peak areas. -- Abstract: A coupling technique of thin-layer electrolysis with high-performance capillary electrophoresis/UV–vis technique(EC/HPCE/UV–vis) is developed for online separation and determination of electrode reaction products. A chip-type thin-layer electrolytic (CTE) cell was designed and fabricated, which contains a capillary channel and a background electrolyte reservoir, allowing rapid electrolysis, direct sampling and online electrophoretic separation. This chip-type setup was characterized based on an electrophoresis expression of Nernst equation that was applied to the redox equilibrium of o-tolidine at different potentials. The utility of the method was demonstrated by separating and determining the electro-oxidation products of quercetin in different pH media. Two main products were always found in the studied time, potential and pH ranges. The variety of products increased not only with increasing potential but also with increasing pH value, and in total, at least 13 products were observed in the electropherograms. This work illustrates a novel example of capillary electrophoresis used online with thin-layer electrolysis to separate and detect electrode reaction products.

  15. A chip-type thin-layer electrochemical cell coupled with capillary electrophoresis for online separation of electrode reaction products

    International Nuclear Information System (INIS)

    He, Jian-Bo; Cui, Ting; Zhang, Wen-Wen; Deng, Ning

    2013-01-01

    Graphical abstract: -- Highlights: •A new coupling of thin-layer electrolysis with capillary electrophoresis (CE). •Rapid electrolysis, direct sampling followed by online CE separation. •At least 13 products of quercetin oxidation were separated. •Thermodynamic and kinetic parameters were determined from CE peak areas. -- Abstract: A coupling technique of thin-layer electrolysis with high-performance capillary electrophoresis/UV–vis technique(EC/HPCE/UV–vis) is developed for online separation and determination of electrode reaction products. A chip-type thin-layer electrolytic (CTE) cell was designed and fabricated, which contains a capillary channel and a background electrolyte reservoir, allowing rapid electrolysis, direct sampling and online electrophoretic separation. This chip-type setup was characterized based on an electrophoresis expression of Nernst equation that was applied to the redox equilibrium of o-tolidine at different potentials. The utility of the method was demonstrated by separating and determining the electro-oxidation products of quercetin in different pH media. Two main products were always found in the studied time, potential and pH ranges. The variety of products increased not only with increasing potential but also with increasing pH value, and in total, at least 13 products were observed in the electropherograms. This work illustrates a novel example of capillary electrophoresis used online with thin-layer electrolysis to separate and detect electrode reaction products

  16. [Thin layer agar represents a cost-effective alternative for the rapid diagnosis of multi-drug resistant tuberculosis].

    Science.gov (United States)

    Hernández-Sarmiento, José M; Martínez-Negrete, Milton A; Castrillón-Velilla, Diana M; Mejía-Espinosa, Sergio A; Mejía-Mesa, Gloria I; Zapata-Fernández, Elsa M; Rojas-Jiménez, Sara; Marín-Castro, Andrés E; Robledo-Restrepo, Jaime A

    2014-01-01

    Using cost-benefit analysis for comparing the thin-layer agar culture method to the standard multiple proportion method used in diagnosing multidrug-resistant tuberculosis (MDR TB). A cost-benefit evaluation of two diagnostic tests was made at the Corporación para Investigaciones Biológicas (CIB) in Medellín, Colombia. 100 patients were evaluated; 10.8% rifampicin resistance and 14.3% isoniazid resistance were found. A computer-based decision tree model was used for cost-effectiveness analysis (Treeage Pro); the thin-layer agar culture method was most cost-effective, having 100% sensitivity, specificity and predictive values for detecting rifampicin and isoniazid resistance. The multiple proportion method value was calculated as being US$ 71 having an average 49 day report time compared to US$ 18 and 14 days for the thin-layer agar culture method. New technologies have been developed for diagnosing tuberculosis which are apparently faster and more effective; their operating characteristics must be evaluated as must their effectiveness in terms of cost-benefit. The present study established that using thin-layer agar culture was cheaper, equally effective and could provide results more quickly than the traditional method. This implies that a patient could receive MDR TB treatment more quickly.

  17. VIII All-Russian symposium on molecular liquid chromatography and capillary electrophoresis. Program. Summary of reports

    International Nuclear Information System (INIS)

    2001-01-01

    Program and summary of reports of the VIII All-Russian symposium on molecular liquid chromatography and capillary electrophoresis are performed. The meeting took place 15-19 October, 2001 in Moscow. Many problems of liquid and ion exchange chromatography, capillary electrophoresis, thin-layer chromatography have been discussed extensively. Reports covering properties of sorbents and devices for chromatography are incorporated in the collection [ru

  18. On-line Automated Sample Preparation-Capillary Gas Chromatography for the Analysis of Plasma Samples.

    NARCIS (Netherlands)

    Louter, A.J.H.; van der Wagt, R.A.C.A.; Brinkman, U.A.T.

    1995-01-01

    An automated sample preparation module, (the automated sample preparation with extraction columns, ASPEC), was interfaced with a capillary gas chromatograph (GC) by means of an on-column interface. The system was optimised for the determination of the antidepressant trazodone in plasma. The clean-up

  19. Facile preparation of organic-silica hybrid monolith for capillary hydrophilic liquid chromatography based on "thiol-ene" click chemistry.

    Science.gov (United States)

    Chen, Ming-Luan; Zhang, Jun; Zhang, Zheng; Yuan, Bi-Feng; Yu, Qiong-Wei; Feng, Yu-Qi

    2013-04-05

    In this work, a one-step approach to facile preparation of organic-inorganic hybrid monoliths was successfully developed. After vinyl-end organic monomers and azobisisobutyronitrile (AIBN) were mixed with hydrolyzed tetramethoxysilane (TMOS) and 3-mercaptopropyltrimethoxysilane (MPTMS), the homogeneous mixture was introduced into a fused-silica capillary for simultaneous polycondensation and "thiol-ene" click reaction to form the organic-silica hybrid monoliths. By employing this strategy, two types of organic-silica hybrid monoliths with positively charged quaternary ammonium and amide groups were prepared, respectively. The functional groups were successfully introduced onto the monoliths during the sol-gel process with "thiol-ene" click reaction, which was demonstrated by ζ-potential assessment, energy dispersive X-ray spectroscopy (EDX), and Fourier transform infrared (FT-IR) spectroscopy. The porous structure of the prepared monolithic columns was examined by scanning electron microscopy (SEM), nitrogen adsorption-desorption measurement, and mercury intrusion porosimetry. These results indicate the prepared organic-silica hybrid monoliths possess homogeneous column bed, large specific surface area, good mechanical stability, and excellent permeability. The prepared monolithic columns were then applied for anion-exchange/hydrophilic interaction liquid chromatography. Different types of analytes, including benzoic acids, inorganic ions, nucleosides, and nucleotides, were well separated with high column efficiency around 80,000-130,000 plates/m. Taken together, we present a facile and universal strategy to prepare organic-silica hybrid monoliths with a variety of organic monomers using one-step approach. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. Forensic examination of ink by high-performance thin layer chromatography--the United States Secret Service Digital Ink Library.

    Science.gov (United States)

    Neumann, Cedric; Ramotowski, Robert; Genessay, Thibault

    2011-05-13

    Forensic examinations of ink have been performed since the beginning of the 20th century. Since the 1960s, the International Ink Library, maintained by the United States Secret Service, has supported those analyses. Until 2009, the search and identification of inks were essentially performed manually. This paper describes the results of a project designed to improve ink samples' analytical and search processes. The project focused on the development of improved standardization procedures to ensure the best possible reproducibility between analyses run on different HPTLC plates. The successful implementation of this new calibration method enabled the development of mathematical algorithms and of a software package to complement the existing ink library. Copyright © 2010 Elsevier B.V. All rights reserved.

  1. Thin-Layer Chromatography of 2-Imino-3-(Substituted Aryl)-1-Thiazolidin- 4-Ones and Their Intermediates, Chloroacetanilides

    OpenAIRE

    Minbale Aschale

    2014-01-01

    International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computa...

  2. Quantitative Determination of Flavonoids and Chlorogenic Acid in the Leaves of Arbutus unedo L. Using Thin Layer Chromatography

    Directory of Open Access Journals (Sweden)

    Željan Maleš

    2013-01-01

    Full Text Available The plant species Arbutus unedo shows numerous beneficial pharmacological effects (antiseptic, antidiabetic, antidiarrheal, astringent, depurative, antioxidant, antihypertensive, antithrombotic, and anti-inflammatory. For the medicinal use, standardization of extracts is a necessity, as different compounds are responsible for different biological activities. In this paper, we analyze monthly changes in the content of quercitrin, isoquercitrin, hyperoside, and chlorogenic acid. Methanolic extracts of the leaves are analyzed by HPTLC for the identification and quantification of individual polyphenol, and DPPH test is used to determine antioxidant activity. Based on the results obtained, the leaves should be collected in January to obtain the highest concentrations of hyperoside and quercitrin (0.35 mg/g and 1.94 mg/g, resp., in June, July, and October for chlorogenic acid (1.45–1.46 mg/g, and for the fraction of quercitrin and isoquercitrin in November (1.98 mg/g and 0.33 mg/g, resp.. Optimal months for the collection of leaves with the maximum recovery of individual polyphenol suggested in this work could direct the pharmacological usage of the polyvalent herbal drugs.

  3. Quantitative Determination of Flavonoids and Chlorogenic Acid in the Leaves of Arbutus unedo L. Using Thin Layer Chromatography.

    Science.gov (United States)

    Maleš, Zeljan; Sarić, Darija; Bojić, Mirza

    2013-01-01

    The plant species Arbutus unedo shows numerous beneficial pharmacological effects (antiseptic, antidiabetic, antidiarrheal, astringent, depurative, antioxidant, antihypertensive, antithrombotic, and anti-inflammatory). For the medicinal use, standardization of extracts is a necessity, as different compounds are responsible for different biological activities. In this paper, we analyze monthly changes in the content of quercitrin, isoquercitrin, hyperoside, and chlorogenic acid. Methanolic extracts of the leaves are analyzed by HPTLC for the identification and quantification of individual polyphenol, and DPPH test is used to determine antioxidant activity. Based on the results obtained, the leaves should be collected in January to obtain the highest concentrations of hyperoside and quercitrin (0.35 mg/g and 1.94 mg/g, resp.), in June, July, and October for chlorogenic acid (1.45-1.46 mg/g), and for the fraction of quercitrin and isoquercitrin in November (1.98 mg/g and 0.33 mg/g, resp.). Optimal months for the collection of leaves with the maximum recovery of individual polyphenol suggested in this work could direct the pharmacological usage of the polyvalent herbal drugs.

  4. Interaction of surfactants with homologous series of peptides studied by reversed-phase thin-layer chromatography

    Czech Academy of Sciences Publication Activity Database

    Cserháti, T.; Forgács, E.; Deyl, Zdeněk; Mikšík, Ivan; Eckhardt, Adam

    2001-01-01

    Roč. 910, č. 1 (2001), s. 137-145 ISSN 0021-9673 R&D Projects: GA ČR GV203/96/K128; GA ČR GA203/99/0191; GA ČR GA203/00/D032 Institutional research plan: CEZ:AV0Z5011922 Keywords : peptides * sodium dodecylsulfate * octaethoxy oleyl alcohol Subject RIV: BH - Optics, Masers, Lasers Impact factor: 2.793, year: 2001

  5. Interaction of hydroxypropyl-beta-cyclodextrin with peptides, studied by reversed-phase thin-layer chromatography

    Czech Academy of Sciences Publication Activity Database

    Gere-Pászti, E.; Cserháti, T.; Forgács, E.; Deyl, Zdeněk; Mikšík, Ivan; Eckhardt, Adam; Illés, Z.

    2005-01-01

    Roč. 28, č. 16 (2005), s. 2619-2632 ISSN 1082-6076 Grant - others:CZ-HU(CZ) Cooperation program Institutional research plan: CEZ:AV0Z50110509 Keywords : cyclodextrin * peptides * nonlinear map Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 0.814, year: 2005

  6. Identification of common horsetail (Equisetum arvense L.; Equisetaceae) using Thin Layer Chromatography versus DNA barcoding

    DEFF Research Database (Denmark)

    Saslis Lagoudakis, Haris; Bruun-Lund, Sam; Iwanycki, Natalie Eva

    2015-01-01

    collections and commercial herbal products. We find that both methods can discriminate between the two species and positively identify E. arvense. The TLC-test is more cost- and time-efficient, but DNA barcoding is more powerful in determining the identity of adulterant species. Our study shows that, although....... palustre L. that can produce toxic alkaloids. As morphology-based identification is often difficult or impossible, the identification of processed material can be aided by molecular techniques. In this study, we explore two molecular identification techniques as methods of testing the purity these products...

  7. The Development of a Tool for Measuring Graduate Students' Topic Specific Pedagogical Content Knowledge of Thin Layer Chromatography

    Science.gov (United States)

    Hale, L. V. A.; Lutter, J. C.; Shultz, G. V.

    2016-01-01

    Graduate students play a critical role in undergraduate education at doctorate granting institutions; but generally have minimal opportunity to develop teaching expertise. Furthermore, little is known about how graduate students develop teaching expertise in this context. We investigated the development of topic-specific pedagogical content…

  8. Use of thin layer chromatography and x-ray fluorescence analysis to evaluation of Leng 3 mobility in soil

    International Nuclear Information System (INIS)

    Tornisielo, Valdemar L.; Furlan, Gilberto R.; Regitano, Jussara B.; Costa, Maria A.; Nascimento Filho, Virgilio L.; Navarro, Angela A.; Simabuco, Silvana M.

    1996-01-01

    'Leng 3' is a product used for wood preservation and its formulation contain a water solution of copper sulfate, boric acid, sulfuric acid and sodium dichromate. The 'Leng 3' mobility in soil was evaluated using TLC coated with soil film and eluted with distilled water. Three different soils of Sao Paulo state, a Sandy Soil (AQ), a Dark red Latossol (LE) and a Latossol Roxo (LR) were evaluated ed. The products were applied on TLC-soil plates then eluted, dried at room temperature, divide in 10 parts of 1.0 cm wide from the application point to the top scratching the soil out to analysis. The determination of chrome and copper were done by energy dispersive X-ray fluorescence technique (ED-XRF) with 238 Pu radioisotopic excitation (3,61 GBq). Boron was determine by conventional chemical method (hot water extraction) of analysis. The results shown that the three elements chrome, copper and boron were mobile in all soils. Copper had the least mobility in the three soils, but boron and chrome showed a high mobility in all soils. The chrome front rate (Rf) in the soil AQ, LE and LR were 0.85, 0.95 while o.85, 0.35, 0.45 for copper. The element boron had a Rf 1.0 for all soils. (author)

  9. Thin-layer chromatography with stationary phase gradient as a method for separation of water-soluble vitamins.

    Science.gov (United States)

    Cimpoiu, Claudia; Hosu, Anamaria; Puscas, Anitta

    2012-02-03

    The group of hydrophilic vitamins play an important role in human health, and their lack or excess produces specific diseases. Therefore, the analysis of these compounds is indispensable for monitoring their content in pharmaceuticals and food in order to prevent some human diseases. TLC was successfully applied in the analysis of hydrophilic vitamins, but the most difficult problem in the simultaneous analysis of all these compounds is to find an optimum stationary phase-mobile phase system due to different chemical characteristics of analytes. Unfortunately structural analogues are difficult to separate in one chromatographic run, and this is the case in hydrophilic vitamins investigations. TLC gives the possibility to perform two-dimensional separations by using stationary phase gradient achieving the highest resolution by combining two systems with different selectivity. The goal of this work was to develop a method of analysis enabling separation of hydrophilic vitamins using TLC with adsorbent gradient. The developed method was used for identifying the water-soluble vitamins in alcoholic extracts of Hippophae rhamnoides and of Ribes nigrum. Copyright © 2011 Elsevier B.V. All rights reserved.

  10. Analytical Method Validation and Determination of Pyridoxine, Nicotinamide, and Caffeine in Energy Drinks Using Thin Layer Chromatography-Densitometry

    Directory of Open Access Journals (Sweden)

    Florentinus Dika Octa Riswanto

    2015-03-01

    Full Text Available Food supplement which contains vitamins and stimulants such as caffeine were classified as energy drink. TLC-densitometry method was chosen to determine the pyridoxine, nicotinamide, and caffeine in the energy drink sample. TLC plates of silica gel 60 F254 was used as the stationary phase and methanol : ethyl acetate : ammonia 25% (134:77:10 was used as the mobile phase. The correlation coefficient for each pyridoxine, nicotinamide, and caffeine were 0.9982, 0.9997, and 0.9966, respectively. Detection and quantitation limits of from the three analytes were 4.05 and 13.51 µg/mL; 13.15 and 43.83 µg/mL; 5.43 and 18.11 µg/mL, respectively. The recovery of pyridoxine, nicotinamide, and caffeine were within the required limit range of 95-105%. The percent of RSD were below the limit value of 5.7% for caffeine and nicotinamide and 8% for pyridoxine. The content amount of pyridoxine in the sample 1 and 2 were 33.59 ± 0.981 and 30.29 ± 2.061 µg/mL, respectively. The content amount of nicotinamide in the sample 1 and 2 were 106.53 ± 3.521 and 98.20 ± 3.648 µg/mL, respectively. The content amount of caffeine in the sample 1 and 2 were 249.50 ± 5.080 and 252.80 ± 2.640 µg/mL, respectively. Robustness test results showed that the most optimal method conditions should be applied for the analysis.

  11. IMPACT OF TROPICAL CONDITIONS ON THIN-LAYER CHROMATOGRAPHY IN ANALYTICAL TOXICOLOGY - HIGH-TEMPERATURES AND MODERATE HUMIDITIES

    NARCIS (Netherlands)

    DEZEEUW, RA; FRANKE, JP; DIK, E; TENDOLLE, W; KAM, BL

    The impact of high temperatures (24 to 39-degrees-C) and low to moderately high humidities (20 to 70%) on the applicability of TLC systems for drug identification was studied during a 6 month climatologic cycle in Burkina Faso (West Africa). In general, the Rf values as observed on the plates were

  12. Phospholipid composition of cell-derived microparticles determined by one-dimensional high-performance thin-layer chromatography

    NARCIS (Netherlands)

    Weerheim, A. M.; Kolb, A. M.; Sturk, A.; Nieuwland, R.

    2002-01-01

    Microparticles in the circulation activate the coagulation system and may activate the complement system via C-reactive protein upon conversion of membrane phospholipids by phospholipases. We developed a sensitive and reproducible method to determine the phospholipid composition of microparticles.

  13. A technique for extraction and Thin Layer Chromatography visualization of fecal bile acids applied to neotropical felid scats

    Directory of Open Access Journals (Sweden)

    Ada Virginia Cazón Narvaez

    1999-06-01

    Full Text Available Fecal bile acid patterns have been used successfully to identify scats. Neotropical felid scats are capable of this biochemical identification because they present low concentrations of plant pigments that would interfere in fecal bile acids detection. However, neotropical felid scats have poor quantities of bile acids, so we developed in this work a proper technique for their extraction, visualization and determination. Twenty eighth feces of seven different felid species, collected from Zoological and Wildlife Parks, were dried and pulverized. The procedure for analyzing feces is : Take one g of pulverized feces and shake for 3 hr at room temperature in 20 ml benzene : methanol; filter and evaporate to 5 ml. Spot on TLC plate and develop in toluene :acetic acid:water. Dry and visualize with anisaldehyde. Field collected scats could be identified by the bile acids pattern revealed by this specific technique and ,then, used as a source of information for distribution, density and food habits studies.Los patrones de ácidos biliares fecales han sido utilizados satisfactoriamente para identificar heces. Las heces de félidos neotropicales son propicias para ser identificadas bioquímicamente, ya que contienen baja concentración de pigmentos vegetales que pudieran interferir en la detección de ácidos biliares. Sin embargo los ácidos biliares se encuentran en bajas concentraciones en las heces, por lo cual desarrollamos en este trabajo una técnica apropiada para su extracción, visualización y determinación. Veintiocho heces de diferentes félidos recolectadas de Zoológicos y Estaciones de Fauna Silvestre fueron secadas y pulverizadas. El procedimiento para analizar las heces es : Tomar un gramo de feca pulverizada y agitar en 20 ml de benceno :metanol a temperatura ambiente durante 3 hr ; luego filtrar y evaporar hasta 5 ml. Sembrar en placa de TLC y desarrollar en tolueno :ác. acético :agua. Secar y revelar con anisaldehído. Las heces recolectadas en el campo podrían ser identificadas a través de los patrones de ácidos biliares evidenciados con esta técnica específica, y ser entonces utilizadas como fuente de información en estudios sobre distribución, densidad y hábito alimenticio.

  14. Micelle Enhanced Fluorimetric and Thin Layer Chromatography Densitometric Methods for the Determination of (± Citalopram and its S - Enantiomer Escitalopram

    Directory of Open Access Journals (Sweden)

    Elham A. Taha

    2009-01-01

    Full Text Available Two sensitive and validated methods were developed for determination of a racemic mixture citalopram and its enantiomer s -(+escitalopram. The first method was based on direct measurement of the intrinsic fluorescence of escitalopram using sodium dodecyl sulfate as micelle enhancer. This was further applied to determine escitalopram in spiked human plasma, as well as in the presence of common and co-administerated drugs. The second method was TLC densitometric based on various chiral selectors was investigated. The optimum TLC conditions were found to be sensitive and selective for identification and quantitative determination of enantiomeric purity of escitalopram in drug substance and drug products. The method can be useful to investigate adulteration of pure isomer with the cheap racemic form.

  15. Ultrasound extraction and thin layer chromatography-flame ionization detection analysis of the lipid fraction in marine mucilage samples.

    Science.gov (United States)

    Mecozzi, M; Amici, M; Romanelli, G; Pietrantonio, E; Deluca, A

    2002-07-19

    This paper reports an analytical procedure based on ultrasound to extract lipids in marine mucilage samples. The experimental conditions of the ultrasound procedure (solvent and time) were identified by a FT-IR study performed on different standard samples of lipids and of a standard humic sample, before and after the sonication treatment. This study showed that diethyl ether was a more suitable solvent than methanol for the ultrasonic extraction of lipids from environmental samples because it allowed to minimize the possible oxidative modifications of lipids due to the acoustic cavitation phenomena. The optimized conditions were applied to the extraction of total lipid amount in marine mucilage samples and TLC-flame ionization detection analysis was used to identify the relevant lipid sub-fractions present in samples.

  16. Preparative separation and purification of bufadienolides from ChanSu by high-speed counter-current chromatography combined with preparative HPLC

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jialian; Zhang, Yongqing, E-mail: fleiv@163.com [College of Pharmacy, Shandong University of Traditional Chinese Medicine, Jinan, Shandong (China); Lin, Yunliang; Wang, Xiao; Fang, Lei; Geng, Yanling [Shandong Analysis and Test Center, Shandong Academy of Sciences, Jinan, Shandong (China); Zhang, Qinde [Shandong College of Traditional Chinese Medicine, Laiyang, Shandong (China)

    2013-09-01

    Eight bufadienolides were successfully isolated and purified from ChanSu by high-speed counter-current chromatography (HSCCC) combined with preparative HPLC (prep-HPLC). First, a stepwise elution mode of HSCCC with the solvent system composed of petroleum ether-ethyl acetate-methanol-water (4:6:4:6, 4:6:5:5, v/v) was employed and four bufadienolides, two partially purified fractions were obtained from 200 mg of crude extract. The partially purified fractions III and VI were then further separated by prepHPLC, respectively, and another four bufadienolides were recovered. Their structures were confirmed by ESI-MS and {sup 1}H-NMR spectra. (author)

  17. Preparative separation and purification of bufadienolides from ChanSu by high-speed counter-current chromatography combined with preparative HPLC

    International Nuclear Information System (INIS)

    Li, Jialian; Zhang, Yongqing; Lin, Yunliang; Wang, Xiao; Fang, Lei; Geng, Yanling; Zhang, Qinde

    2013-01-01

    Eight bufadienolides were successfully isolated and purified from ChanSu by high-speed counter-current chromatography (HSCCC) combined with preparative HPLC (prep-HPLC). First, a stepwise elution mode of HSCCC with the solvent system composed of petroleum ether–ethyl acetate–methanol–water (4:6:4:6, 4:6:5:5, v/v) was employed and four bufadienolides, two partially purified fractions were obtained from 200 mg of crude extract. The partially purified fractions III and VI were then further separated by prepHPLC, respectively, and another four bufadienolides were recovered. Their structures were confirmed by ESI-MS and 1 H-NMR spectra. (author)

  18. Outdoor corrosion of zinc coated carbon steel, determined by thin layer activation

    International Nuclear Information System (INIS)

    Agostini, M.L.; Laguzzi, G.; De Cristofaro, N.; Stroosnijder, M.F.

    2001-01-01

    Thin Layer Activation was applied in the frame of a European programme addressed to the evaluation of the corrosion the behaviour of different steels. This included outdoor exposure of zinc coated carbon steel in a rural-marine climatic environment, for a period of several months. The zinc layer of specimens was 10 micrometers thick. For the TLA studies 65Zn radio nuclides were produced along the full depth of the coating, by a cyclotron accelerated deuteron beam. For quantification of the material release, activity versus depth was determined using different thickness of Zn coatings on top the carbon steel. After exposure corrosion product were removed from the surface using a pickling solution and the residual activity was determined by gamma spectrometry. The high sensitivity of the method allowed the evaluation of relatively small thickness losses (i.e. 1.2 micrometer). Thickness loss results, obtained by the TLA method, were compared with those arising from the Atomic Absorption analysis of zinc detected in the pickling solutions. A good agreement was observed between the different methods

  19. Investigation of Thin Layered Cobalt Oxide Nano-Islands on Gold

    Science.gov (United States)

    Bajdich, Michal; Walton, Alex S.; Fester, Jakob; Arman, Mohammad A.; Osiecki, Jacek; Knudsen, Jan; Vojvodic, Aleksandra; Lauritsen, Jeppe V.

    2015-03-01

    Layered cobalt oxides have been shown to be highly active catalysts for the oxygen evolution reaction (OER), but the synergistic effect of contact with gold is yet to be fully understood. The synthesis of three distinct types of thin-layered cobalt oxide nano-islands supported on a single crystal gold (111) substrate is confirmed by combination of STM and XAS methods. In this work, we present DFT+U theoretical investigation of above nano-islands using several previously known structural models. Our calculations confirm stability of two low-oxygen pressure phases: (a) rock-salt Co-O bilayer and (b) wurtzite Co-O quadlayer and single high-oxygen pressure phase: (c) O-Co-O trilayer. The optimized geometries agree with STM structures and calculated oxidation states confirm the conversion from Co2+ to Co3+ found experimentally in XAS. The O-Co-O trilayer islands have the structure of a single layer of CoOOH proposed to be the true active phase for OER catalyst. For that reason, the effect of water on the Pourbaix stabilities of basal planes and edge sites is fully investigated. Lastly, we also present the corresponding OER theoretical overpotentials.

  20. Thin layer convective solar drying and mathematical modeling of prickly pear peel (Opuntia ficus indica)

    International Nuclear Information System (INIS)

    Lahsasni, Siham; Kouhila, Mohammed; Mahrouz, Mostafa; Idlimam, Ali; Jamali, Abdelkrim

    2004-01-01

    This paper presents the thin layer convective solar drying and mathematical modeling of prickly pear peel. For these purposes, an indirect forced convection solar dryer consisting of a solar air collector, an auxiliary heater, a circulation fan and a drying cabinet is used for drying experiments. Moreover, the prickly pear peel is sufficiently dried in the ranges of 32 to 36 deg. C of ambient air temperature, 50 to 60 deg. C of drying air temperature, 23 to 34% of relative humidity, 0.0277 to 0.0833 m 3 /s of drying air flow rate and 200 to 950 W/m 2 of daily solar radiation. The experimental drying curves show only a falling drying rate period. The main factor in controlling the drying rate was found to be the drying air temperature. The drying rate equation is determined empirically from the characteristic drying curve. Also, the experimental drying curves obtained were fitted to a number of mathematical models. The Midilli-Kucuk drying model was found to satisfactorily describe the solar drying curves of prickly pear peel with a correlation coefficient (r) of 0.9998 and chi-square (χ 2 ) of 4.6572 10 -5

  1. Thin layer convective solar drying and mathematical modeling of prickly pear peel (Opuntia ficus indica)

    Energy Technology Data Exchange (ETDEWEB)

    Lahsasni, S.; Mahrouz, M. [Unite de Chimie Agroalimentaire (LCOA), Faculte des Sciences Semlalia, Marrakech (Morocco); Kouhila, M.; Idlimam, A.; Jamali, A. [Ecole Normale Superieure, Marrakech (Morocco). Lab. d' Energie Solaire et Plantes Aromatiques et Medicinales

    2004-02-01

    This paper presents the thin layer convective solar drying and mathematical modeling of prickly pear peel. For these purposes, an indirect forced convection solar dryer consisting of a solar air collector, an auxiliary heater, a circulation fan and a drying cabinet is used for drying experiments. Moreover, the prickly pear peel is sufficiently dried in the ranges of 32 to 36 {sup o} C of ambient air temperature, 50 to 60 {sup o}C of drying air temperature, 23 to 34% of relative humidity, 0.0277 to 0.0833 m{sup 3}/s of drying air flow rate and 200 to 950 W/m{sup 2} of daily solar radiation. The experimental drying curves show only a falling drying rate period. The main factor in controlling the drying rate was found to be the drying air temperature. The drying rate equation is determined empirically from the characteristic drying curve. Also, the experimental drying curves obtained were fitted to a number of mathematical models. The Midilli-Kucuk drying model was found to satisfactorily describe the solar drying curves of prickly pear peel with a correlation coefficient (r) of 0.9998 and chi-square ({chi}{sup 2}) of 4.6572 10{sup -5}. (Author)

  2. Interfacial Microstructure and Its Influence on Resistivity of Thin Layers Copper Cladding Steel Wires

    Science.gov (United States)

    Li, Hongjuan; Ding, Zhimin; Zhao, Ruirong

    2018-04-01

    The interfacial microstructure and resistivity of cold-drawn and annealed thin layers copper cladding steel (CCS) wires have been systematically investigated by the methods of scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), and resistivity testing. The results showed that the Cu and Fe atoms near interface diffused into each other matrixes. The Fe atoms diffused into Cu matrixes and formed a solid solution. The mechanism of solid solution is of substitution type. When the quantity of Fe atoms exceeds the maximum solubility, the supersaturated solid solution would form Fe clusters and decompose into base Cu and α-Fe precipitated phases under certain conditions. A few of α-Fe precipitates was observed in the copper near Cu/Fe interfaces of cold-drawn CCS wires, with 1-5 nm in size. A number of α-Fe precipitates of 1-20 nm in size can be detected in copper near Cu/Fe interfaces of CCS wires annealed at 850°C. When annealing temperature was less than 750°C, the resistivity of CCS wires annealed was lower than that of cold-drawn CCS wires. However, when annealing temperature was above 750°C, the resistivity of CCS wires was greater than that of cold-drawn CCS wires and increased with rising the annealing temperature. The relationship between nanoscale α-Fe precipitation and resistivity of CCS wires has been well discussed.

  3. Application of thin layer activation technique for monitoring corrosion of carbon steel in hydrocarbon processing environment.

    Science.gov (United States)

    Saxena, R C; Biswal, Jayashree; Pant, H J; Samantray, J S; Sharma, S C; Gupta, A K; Ray, S S

    2018-05-01

    Acidic crude oil transportation and processing in petroleum refining and petrochemical operations cause corrosion in the pipelines and associated components. Corrosion monitoring is invariably required to test and prove operational reliability. Thin Layer Activation (TLA) technique is a nuclear technique used for measurement of corrosion and erosion of materials. The technique involves irradiation of material with high energy ion beam from an accelerator and measurement of loss of radioactivity after the material is subjected to corrosive environment. In the present study, TLA technique has been used to monitor corrosion of carbon steel (CS) in crude oil environment at high temperature. Different CS coupons were irradiated with a 13 MeV proton beam to produce Cobalt-56 radioisotope on the surface of the coupons. The corrosion studies were carried out by subjecting the irradiated coupons to a corrosive environment, i.e, uninhibited straight run gas oil (SRGO) containing known amount of naphthenic acid (NA) at high temperature. The effects of different parameters, such as, concentration of NA, temperature and fluid velocity (rpm) on corrosion behaviour of CS were studied. Copyright © 2018 Elsevier Ltd. All rights reserved.

  4. Electrografting of carboxyphenyl thin layer onto gold for DNA and enzyme immobilization

    International Nuclear Information System (INIS)

    Nowicka, Anna M.; Fau, Michal; Kowalczyk, Agata; Strawski, Marcin; Stojek, Zbigniew

    2014-01-01

    The convenient functionalization of metal surfaces by carboxyphenyl groups in aprotic media is not possible for two reasons. First, carboxy derivatives of diazonium salts are very unstable and, second, the electroreduction product is soluble in the solvent. So, the optimization of the conditions of the electrografting of the metal surfaces by applying aqueous solutions is much needed. Compared to earlier cyclic voltammetry approaches we have shown that the chronoamperometric deposition is more convenient. The constant potential equal to the voltammetric peak potential and the molar ratio 1:1 for the substrates: 4-aminobenzoic acid and NaNO 2 as the diazotization agent, in 0.5 M HCl, appeared to be very satisfying conditions for the deposition of a thin layer of deposit of perpendicularly oriented carboxyphenyl groups at the Au surface and for maximal elimination of the influence of the side-reactions products. Under the determined conditions the immobilization of DNA strands was optimal and the deposited laccase layer was tightly packed and very efficient toward the electroreduction of oxygen. Electrochemical impedance spectroscopy, electrochemical quartz crystal microbalance, cyclic voltammetry, chronocoulometry, atomic force microscopy, contact angle measurements and UV–Vis spectroscopy of the solution were used to characterize the electrografted carboxyphenyl layers and subsequent oligonucleotide and enzyme immobilization process

  5. Development of counting system for wear measurements using Thin Layer Activation and the Wearing Apparatus

    Energy Technology Data Exchange (ETDEWEB)

    França, Michel de A.; Suita, Julio C.; Salgado, César M., E-mail: mchldante@gmail.com, E-mail: suita@ien.gov.br, E-mail: otero@ien.gov.br [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2017-07-01

    This paper focus on developing a counting system for the Wearing Apparatus, which is a device previously built to generate measurable wear on a given surface (Main Source) and to carry the fillings from it to a filter (second source). The Thin Layer Activation is a technique used to produce activity on one of the Wearing Apparatus' piece, this activity is proportional to the amount of material worn, or scrapped, from the piece's surface. Thus, by measuring the activity on those two points it is possible to measure the produced wear. The methodology used in this work is based on simulations through MCNP-X Code to nd the best specifications for shielding, solid angles, detectors dimensions and collimation for the Counting System. By simulating several scenarios, each one different from the other, and analyzing the results in the form of Counts Per Second, the ideal counting system's specifications and geometry to measure the activity in the Main Source and the Filter (second source) is chosen. After that, a set of previously activated stainless steel foils were used to reproduce the real experiments' conditions, this real experiment consists of using TLA and the Wearing Apparatus, the results demonstrate that the counting system and methodology are adequate for such experiments. (author)

  6. Electroluminescence of organic light-emitting diodes with an ultra-thin layer of dopant

    Energy Technology Data Exchange (ETDEWEB)

    Li Weizhi [State Key Lab of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China); Yu Junsheng [State Key Lab of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China)], E-mail: jsyu@uestc.edu.cn; Wang, Tao [State Key Lab of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China); Jiang, Yadong [State Key Lab of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China)], E-mail: jiangyd@uestc.edu.cn; Wei, Bangxiong [State Key Lab of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China)

    2008-03-15

    Conventional fluorescent dyes, i.e., 4-(dicyanomethylene)-2-t-butyl-6(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB), 5,12-dihydro-5,12-dimethylquino [2,3-b]acridine-7,14-dione (DMQA) and 5,6,11,12-tetraphenylnaphthacene (Rubrene), were used to investigate the performance of organic light-emitting diodes (OLEDs) based on indium tin oxide (ITO)/N,N'-bis-(1-naphthyl)-N,N'-diphenyl-1,1'-biphenyl-4,4'-diamine (NPB)/tris-(8-hydroxyquinolate)-aluminum (Alq{sub 3})/MgAg. The dyes were either inserted into devices as an ultra-thin film at the NPB/Alq{sub 3} interface by sequential evaporation, or doped into the Alq{sub 3} emission layer by co-evaporation with the doping ratio about 2%. Electroluminescence (EL) spectra of devices indicated that concentration quenching effect (CQE) of the dye-dopant was slightly bigger in the former than in the latter, while the degrees of CQE for three dopants are in the order of DMQA > DCJTB > Rubrene suggested by the difference in EL spectra and performances of devices. In addition, EL process of device with an ultra-thin layer of dopant is dominated by direct carrier trapping (DCT) process due to almost no holes recombine with electrons in Alq{sub 3}-host layer.

  7. Investigation of anti-wear performance of automobile lubricants using thin layer activation analysis technique

    Energy Technology Data Exchange (ETDEWEB)

    Biswal, Jayashree [Isotope and Radiation Application Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Thakre, G.D. [Tribology and Combustion Division, Indian Institute of Petroleum, Dehradun 248005, Uttarakhand (India); Pant, H.J., E-mail: hjpant@barc.gov.in [Isotope and Radiation Application Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Samantray, J.S. [Isotope and Radiation Application Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Arya, P.K. [Tribology and Combustion Division, Indian Institute of Petroleum, Dehradun 248005, Uttarakhand (India); Sharma, S.C.; Gupta, A.K. [Nuclear Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)

    2017-05-15

    An investigation was carried out to examine the anti-wear behavior of automobile lubricants using thin layer activation analysis technique. For this study disc gears made of EN 31 steel were labeled with a small amount of radioactivity by irradiating with 13 MeV proton beam from a particle accelerator. Experiments on wear rate measurement of the gear were carried out by mounting the irradiated disc gear on a twin-disc tribometer under lubricated condition. The activity loss was monitored by using a NaI(Tl) scintillation detector integrated with a multichannel analyzer. The relative remnant activity was correlated with thickness loss by generating a calibration curve. The wear measurements were carried out for four different types of lubricants, named as, L1, L2, L3 and L4. At lower load L1 and L4 were found to exhibit better anti-wear properties than L2 and L3, whereas, L4 exhibited the best anti-wear performance behavior than other three lubricants at all the loads and speeds investigated.

  8. Thin layer drying kinetics of by-products from olive oil processing.

    Science.gov (United States)

    Montero, Irene; Miranda, Teresa; Arranz, Jose Ignacio; Rojas, Carmen Victoria

    2011-01-01

    The thin-layer behavior of by-products from olive oil production was determined in a solar dryer in passive and active operation modes for a temperature range of 20-50 °C. The increase in the air temperature reduced the drying time of olive pomace, sludge and olive mill wastewater. Moisture ratio was analyzed to obtain effective diffusivity values, varying in the oil mill by-products from 9.136 × 10(-11) to 1.406 × 10(-9) m(2)/s in forced convection (m(a) = 0.22 kg/s), and from 9.296 × 10(-11) to 6.277 × 10(-10) m(2)/s in natural convection (m(a) = 0.042 kg/s). Diffusivity values at each temperature were obtained using the Fick's diffusion model and, regardless of the convection, they increased with the air temperature. The temperature dependence on the effective diffusivity was determined by an Arrhenius type relationship. The activation energies were found to be 38.64 kJ/mol, 30.44 kJ/mol and 47.64 kJ/mol for the olive pomace, the sludge and the olive mill wastewater in active mode, respectively, and 91.35 kJ/mol, 14.04 kJ/mol and 77.15 kJ/mol in natural mode, in that order.

  9. Calanoid Copepod Behavior in Thin Layer Shear Flows: Freshwater Versus Marine

    Science.gov (United States)

    Skipper, A. N.; Webster, D. R.; Yen, J.

    2015-11-01

    Marine copepods have been shown to behaviorally respond to vertical gradients of horizontal velocity and aggregate around thin layers. The current study addresses whether a freshwater copepod from an alpine lake demonstrates similar behavior response. Hesperodiaptomus shoshone is often the greatest biomass in alpine lakes and is the dominant zooplankton predator within its environment. The hypothesis is that H. shoshone responds to vertical gradients of horizontal velocity, which are associated with river outflows from alpine lakes, with fine-scale changes in swimming kinematics. The two calanoid copepods studied here, H. shoshone (freshwater) and Calanus finmarchicus(marine), are of similar size (2 - 4 mm), have similar morphologies, and utilize cruising as their primary swimming mode. The two animals differ not only in environment, but also in diet; H. shoshone is a carnivore, whereas C. finmarchicusis an herbivore. A laminar, planar jet (Bickley) was used in the laboratory to simulate a free shear flow. Particle image velocimetry (PIV) quantified the flow field. The marine species changed its swimming behavior significantly (increased swimming speed and turning frequency) and spent more time in the layer (40% vs. 70%) from control to treatment. In contrast, the freshwater species exhibited very few changes in either swimming behavior or residence time. Swimming kinematics and residence time results were also similar between males and females. Unlike the marine copepod, the results suggest the environmental flow structure is unimportant to the freshwater species.

  10. Moessbauer and XRD study of pulse plated Fe-P and Fe-Ni thin layers

    Energy Technology Data Exchange (ETDEWEB)

    Miko, Annamaria [Bay Zoltan Institute for Material Science (Hungary); Kuzmann, Erno, E-mail: kuzmann@para.chem.elte.hu [Eoetvoes Lorand University, Research Group for Nuclear Methods in Structural Chemistry, Hungarian Academy of Sciences, Department of Nuclear Chemistry (Hungary); Lakatos-Varsanyi, Magda [Bay Zoltan Institute for Material Science (Hungary); Kakay, Attila [Research Institute for Solid State Physics and Optics (Hungary); Nagy, Ferenc [Eoetvoes Lorand University, Research Group for Nuclear Methods in Structural Chemistry, Hungarian Academy of Sciences, Department of Nuclear Chemistry (Hungary); Varga, Lajos Karoly [Research Institute for Solid State Physics and Optics (Hungary)

    2005-09-15

    {sup 57}Fe conversion electron Moessbauer spectroscopy, X-ray diffraction, electrochemical and magnetic measurements were used to study pulse electroplated Fe-P and Ni-Fe coatings. XRD and {sup 57}Fe CEMS measurements revealed the amorphous character of the novel pulse plated Fe-P alloys. CEM spectra indicated significant differences in the short range order and in the magnetic anisotropy between the Fe-P deposits pulse plated at medium long deposition time (t{sub on} = 2 ms), with short relaxation time (t{sub off} = 9 ms) and low current density (I{sub p} = 0.05 Acm{sup -2}) or at short deposition time (t{sub on} = 1 ms) with long relaxation time (t{sub off} = 250 ms) and high current density (I{sub p} = 1.0 Acm{sup -2}). The broad peaks centred around the fcc reflections in XRD of the pulse plated Ni-22 wt.% Fe deposit reflected a microcrystalline Ni-Fe alloy with a very fine, 5-8 nm, grain size. The CEM spectrum of the pulse plated Ni-22 wt.% Fe coating corresponded to a highly disordered solid solution alloy containing a minute amount of ferrihydrite. Extreme favourable soft magnetic properties were observed with these Ni-Fe and Fe-P pulse plated thin layers.

  11. Moessbauer and XRD study of pulse plated Fe-P and Fe-Ni thin layers

    International Nuclear Information System (INIS)

    Miko, Annamaria; Kuzmann, Erno; Lakatos-Varsanyi, Magda; Kakay, Attila; Nagy, Ferenc; Varga, Lajos Karoly

    2005-01-01

    57 Fe conversion electron Moessbauer spectroscopy, X-ray diffraction, electrochemical and magnetic measurements were used to study pulse electroplated Fe-P and Ni-Fe coatings. XRD and 57 Fe CEMS measurements revealed the amorphous character of the novel pulse plated Fe-P alloys. CEM spectra indicated significant differences in the short range order and in the magnetic anisotropy between the Fe-P deposits pulse plated at medium long deposition time (t on = 2 ms), with short relaxation time (t off = 9 ms) and low current density (I p = 0.05 Acm -2 ) or at short deposition time (t on = 1 ms) with long relaxation time (t off = 250 ms) and high current density (I p = 1.0 Acm -2 ). The broad peaks centred around the fcc reflections in XRD of the pulse plated Ni-22 wt.% Fe deposit reflected a microcrystalline Ni-Fe alloy with a very fine, 5-8 nm, grain size. The CEM spectrum of the pulse plated Ni-22 wt.% Fe coating corresponded to a highly disordered solid solution alloy containing a minute amount of ferrihydrite. Extreme favourable soft magnetic properties were observed with these Ni-Fe and Fe-P pulse plated thin layers.

  12. Supercritical fluid chromatography for separation and preparation of tautomeric 7-epimeric spiro oxindole alkaloids from Uncaria macrophylla.

    Science.gov (United States)

    Yang, Wenzhi; Zhang, Yibei; Pan, Huiqin; Yao, Changliang; Hou, Jinjun; Yao, Shuai; Cai, Luying; Feng, Ruihong; Wu, Wanying; Guo, Dean

    2017-02-05

    Increasing challenge arising from configurational interconversion in aqueous solvent renders it rather difficult to isolate high-purity tautomeric reference standards and thus largely hinders the holistic quality control of traditional Chinese medicine (TCM). Spiro oxindole alkaloids (SOAs), as the markers for the medicinal Uncaria herbs, can easily isomerize in polar or aqueous solvent via a retro-Mannich reaction. In the present study, supercritical fluid chromatography (SFC) is utilized to separate and isolate two pairs of 7-epimeric SOAs, including rhynchophylline (R) and isorhynchophylline (IR), corynoxine (C) and corynoxine B (CB), from Uncaria macrophylla. Initially, the solvent that can stabilize SOA epimers was systematically screened, and acetonitrile was used to dissolve and as the modifier in SFC. Then, key parameters of ultra-high performance SFC (ultra-performance convergence chromatography, UPC 2 ), comprising stationary phase, additive in modifier, column temperature, ABPR pressure, and flow rate, were optimized in sequence. Two isocratic UPC 2 methods were developed on the achiral Torus 1-AA and Torus Diol columns, suitable for UV and MS detection, respectively. MCI gel column chromatography fractionated the U. macrophylla extract into two mixtures (R/IR and C/CB). Preparative SFC, using a Viridis Prep Silica 2-EP OBD column and acetonitrile-0.2% diethylamine in CO 2 as the mobile phase, was finally employed for compound purification. As a result, the purity of four SOA compounds was all higher than 95%. Different from reversed-phase HPLC, SFC, by use of water-free mobile phase (inert CO 2 and aprotic modifier), provides a solution to rapid analysis and isolation of tautomeric reference standards for quality control of TCM. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Perfusion chromatography separation of the tomato fruit-specific pectin methylesterase from a semipurified commercial enzyme preparation.

    Science.gov (United States)

    Savary, B J

    2001-08-01

    A rapid and simple method was developed, using perfusion chromatography media, to separate the fruit-specific pectin methylesterase (PME) isoform from the depolymerizing enzyme polygalacturonase (PG) and other contaminating pectinases present in a commercial tomato enzyme preparation. Pectinase activities were adsorbed onto a Poros HS (a strong cation exchanger) column in 20 M HEPES buffer at pH 7.5. The fruit-specific PME was eluted from the column with 80 mM NaCl, followed by a step to 300 mM NaCl to elute PG activity. Rechromatography of the PME activity peak with a linear gradient further resolved two PME isoenzymes and removed residual traces of PG activity. The PG activity peak was further treated with lectin affinity chromatography to provide purified PG enzyme, which was separated from a salt-dependent PME (tentatively identified as a "ubiquitous-type" isoform), and a pectin acetylesterase. The later enzyme has not been reported previously in tomato. This method provides monocomponent enzymes that will be useful for studying enzyme mechanisms and for modifying pectin structure and functional properties.

  14. Simultaneous determination of artificial sweeteners, preservatives, caffeine, theobromine and theophylline in food and pharmaceutical preparations by ion chromatography.

    Science.gov (United States)

    Chen, Q C; Wang, J

    2001-12-07

    A novel ion chromatographic method was proposed for the simultaneous determination of artificial sweeteners (sodium saccharin, aspartame, acesulfame-K), preservatives (benzoic acid, sorbic acid), caffeine, theobromine and theophylline. The separation was performed on an anion-exchange analytical column operated at 40 degrees C within 45 min by an isocratic elution with 5 mM aqueous NaH2PO4 (pH 8.20) solution containing 4% (v/v) acetonitrile as eluent, and the determination by wavelength-switching ultraviolet absorbance detection. The detection limits (signal-to-noise ratio 3:1) for all analytes were below the sub-microg/ml level. Under the experimental conditions, several organic acids, including citric acid, malic acid, tartaric acid and ascorbic acid, did not interfere with the determination. The method has been successfully applied to the analysis of various food and pharmaceutical preparations, and the average recoveries for real samples ranged from 85 to 104%. The levels of all analytes determined by this method were in good agreement with those obtained by the high-performance liquid chromatographic procedure. The results also indicated that ion chromatography would be possibly a beneficial alternative to conventional high-performance liquid chromatography for the separation and determination of these compounds.

  15. Isolation of Flavonoids From Wild Aquilaria sinensis Leaves by an Improved Preparative High-Speed Counter-Current Chromatography Apparatus.

    Science.gov (United States)

    Yang, Mao-Xun; Liang, Yao-Guang; Chen, He-Ru; Huang, Yong-Fang; Gong, Hai-Guang; Zhang, Tian-You; Ito, Yoichiro

    2018-01-01

    Four flavonoids including apigenin-7,4'-dimethylether, genkwanin, quercetin, and kaempferol were isolated in a preparative or semi-preparative scale from the leaves of wild Aquilaria sinensis using an improved preparative high-speed counter-current chromatography apparatus. The separations were performed with a two-phase solvent system composed of hexane-ethyl acetate, methanol-water at suitable volume ratios. The obtained fractions were analyzed by HPLC, and the identification of each target compound was carried out by ESI-MS and NMR. The yields of the above four target flavonoids were 4.7, 10.0, 11.0 and 4.4%, respectively. All these four flavonoids exhibited nitrite scavenging activities with the clearance rate of 12.40 ± 0.20%, 5.84 ± 0.03%, 28.10 ± 0.17% and 5.19 ± 0.11%, respectively. Quercetin was originally isolated from the Thymelaeaceae family, while kaempferol was isolated from the Aquilaria genus for the first time. In cytotoxicity test these two flavonoids exhibited moderate inhibitory activities against HepG2 cells with the IC50 values of 12.54 ± 1.37 and 38.63 ± 4.05 μM, respectively. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  16. Preparative isolation by high performance liquid chromatography of human insulin B chain produced in escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

    Cruz, N.; Antonio, S.; De Anda, R.; Gosset, G.; Bolivar, F. (Centro de Investigacion sobre Ingenieria Genetica y Biotecnologia, Universidad Nacional Autonoma de Mexico, Apdo. Postal 510-3 Cuernavaca, Mor. 62271 (MX))

    1990-01-01

    This paper reports on a simple method developed for the analytical and preparative purification of human insulin B chain from recombinant origin. Three solvent systems: acetonitrile, isopropanol and methanol, were studied to determine their capacity to resolve the insulin B chain from a mixture of cyanogen bromide generated bacterial peptides. Using a {mu}Bondapak C18 column, it was possible to resolve the insulin B chain in all three systems. On a preparative scale, using a PrePak 500 C18 column with the isopropanol system, it was possible to purify insulin B chain and to obtain a 95% protein recovery.

  17. Ascorbic acid surface modified TiO₂-thin layers as a fully integrated analysis system for visual simultaneous detection of organophosphorus pesticides.

    Science.gov (United States)

    Li, Shunxing; Liang, Wenjie; Zheng, Fengying; Lin, Xiaofeng; Cai, Jiabai

    2014-11-06

    TiO₂ photocatalysis and colorimetric detection are coupled with thin layer chromatography (TLC) for the first time to develop a fully integrated analysis system. Titania@polystyrene hybrid microspheres were surface modified with ascorbic acid, denoted AA-TiO₂@PS, and used as the stationary phase for TLC. Because the affinity between AA-TiO₂@PS and organophosphorus pesticides (OPs) was different for different species of OPs (including chlopyrifos, malathion, parathion, parathion-methyl, and methamidophos), OPs could be separated simultaneously by the mobile phase in 12.0 min with different Rf values. After surface modification, the UV-vis wavelength response range of AA-TiO₂@PS was expanded to 650 nm. Under visible-light irradiation, all of the OPs could be photodegraded to PO₄(3-) in 25.0 min. Based on the chromogenic reaction between PO₄(3-) and chromogenic agents (ammonium molybdate and ascorbic acid), OPs were quantified from color intensity images using a scanner in conjunction with image processing software. So, AA-TiO₂@PS was respectively used as the stationary phase of TLC for efficient separation of OPs, as a photocatalyst for species transformation of phosphorus, and as a colorimetric probe for on-field simultaneous visual detection of OPs in natural water. Linear calibration curves for each OP ranged from 19.3 nmol P L(-1) to 2.30 μmol P L(-1). This integrated analysis system was simple, inexpensive, easy to operate, and sensitive.

  18. Thin Layer Chromatographic Resolution of Some β-adrenolytics and a β2-Agonist Using Bovine Serum Albumin as Chiral Additive in Stationary Phase.

    Science.gov (United States)

    Malik, Poonam; Bhushan, Ravi

    2018-01-01

    Direct enantiomeric resolution of commonly used five racemic β-adrenolytics, namely, bisoprolol, atenolol, propranolol, salbutamol and carvedilol has been achieved by thin layer chromatography using bovine serum albumin (BSA) as chiral additive in stationary phase. Successful resolution of the enantiomers of all racemic β-adrenolytics was achieved by use of different composition of simple organic solvents having no buffer or inorganic ions. The effect of variation in pH, temperature, amount of BSA as the additive, and composition of mobile phase on resolution was systematically studied. Spots were visualized in iodine vapors. Native enantiomers for each of the five analytes were isolated and identified and their elution order was determined. The limit of detection was found to be 0.7, 1.2, 0.84, 1.6 and 0.9 μg (per spot) for each enantiomer of bisoprolol, atenolol, propranolol, salbutamol and carvedilol, respectively. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  19. Examples of the use of preparative gas-phase chromatography for producing marked molecules; Exemples d'emploi de la chromatographie gazeuse preparative dans la fabrication des molecules marquees

    Energy Technology Data Exchange (ETDEWEB)

    Pichat, L; Baret, Ch; Guermont, J P; Audinot, M [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1960-07-01

    Gas chromatography is most wildly used in the analysis of volatile products. Certain works mention its use for preparatory purposes. Organic labelled molecule preparations are usually made in respect of quantities of the order of 1-10 mmol. It has thus been possible to use gas chromatography with very little alteration for the purification of C-14 labelled molecules and their separation from complex reaction mixtures. The apparatus employed may be briefly described as follows. The chromatography columns used (diameter: 9-12 mm, length: approximately 4-6 m) made it possible to separate labelled products with boiling-points of up to 180 deg. C and in quantities of approximately 100 mg to 1 g. The fractions detected by a conventional conductivity cell device were condensed in traps cooled by liquid nitrogen. The radioactivity was not measured at the same time, as an ionization chamber capable of operating at up to 100 deg. C is still only at the research stage. In all cases, the vector gas was helium and the stationary phase support was usually 80 mesh 'celite 545'. The acetone-2-C{sup 14} produced by pyrolysis of barium acetate was purified on a 'polyglycol 200' column. The water and any unidentified impurities are readily eliminated. The benzene C{sub 6}{sup 14} produced by cyclizing polymerization of the acetylene-C{sup 14} in acetonitril was quantitatively separated from the complex reaction mixture on a nonyl phthalate column at 80 deg. C. The methyl or ethyl acrylates formed, according to Reppe, by the action of radioactive acetylene on a mixture of methanol or ethanol, water an hydrochloric acid, in the presence of nickel carbonyl, are difficult to separate by distillation in small quantities. Two columns were used in series: one consisted of a 'Linde 5 A' molecular sieve having a triple purpose: fixation of the water, fixation of the methanol and neutralization of the hydrochloric acid; the second column composed of nonyl phthalate brought about separation of

  20. Simple preparation of new N-aryl-N-(3-indolmethyl acetamides and their spectroscopic analysis

    Directory of Open Access Journals (Sweden)

    José A. Henao

    2009-12-01

    Full Text Available To prepare new indolic molecules and characterize them by spectroscopic methods. Materials and methods: All reagentswere purchased from Aldrich, commercial grade. The purity of the products and the composition of the reaction mixtures were monitoredby thin layer chromatography over Silufol UV254 0.25 mm-thick chromatoplates. Product isolation and purification were performed bycolumn chromatography (SiO2, using ethyl acetate-petroleum ether mixtures as eluents. Results. The synthesis of new N-aryl-N-(3-indolmethyl acetamides based on first step iminization reaction of indol-3-carbaldehyde is accomplished. The structures of the C-3substituted indoles were confirmed by 1H-NMR and 13C-NMR studies supported by inverse-detected 2D NMR experiments and alsothrough monocrystal X-ray diffraction. Conclusions. An efficient, economic, and fast synthetic route was designed to the construction ofthe N-aryl-N-(3-indolmethyl acetamides, structural analogues of some alkaloids.

  1. Preparation, quality control and physico-chemical properties of 99mTc-BAT-AV-45

    International Nuclear Information System (INIS)

    Jiankang Zhang; Xingqin Zhou; Xiaofeng Qin

    2012-01-01

    One novel styrylpyridine derivatives(AV-45) coupled with 99m Tc complex was synthesized. 99m Tc-BAT-AV-45 was prepared by a ligand exchange reaction employing sodium glucoheptonate, and effects of the amount of ligand, stannous chloride, sodium glucoheptonate and pH value of reaction mixture on the radiolabeling yield were studied in details. Quality control was performed by thin layer chromatography and high performance liquid chromatography. Besides the stability, partition coefficient and electrophoresis of 99m Tc-BAT-AV-45 were also investigated. The results showed that the average radiolabeling yield was (95 ± 1%) and 99m Tc-BAT-AV-45 with suitable lipophilicity was stable and uncharged at physiological pH. (author)

  2. Preparation and bioevaluation of 99mTc-carbonyl complex of guanine

    International Nuclear Information System (INIS)

    Cigdem Ichedef; Serap Teksoez; Kamile Senocak; Eser Ucar; Ayfer Yurt Kilcar

    2011-01-01

    The aim of this study is to prepare radiolabeled guanine with 99m Tc(CO) 3 + core. For this purpose, guanine has been radiolabeled with 99m Tc(CO) 3 + core. Quality control study of radiolabeled guanine molecule with 99m Tc(CO) 3 + core was performed by thin layer radio chromatography (TLRC) and high performance liquid radio chromatography (HPLRC). The results showed that the radiolabeling yield was quite high (94 ± 3%). Beside that 99m Tc(CO) 3 -Gua complex has showed good in vitro stability during the 24 h period. Radiopharmaceutical potential of this complex was evaluated in Wistar Albino Rats. It was concluded that 99m Tc(CO) 3 -Gua could be used as a nucleotide radiopharmaceutical for in vivo applications. (author)

  3. Preparation and characterization of 125I labeled progesterone derivatives for the development of a radioimmunoassay for progesterone

    International Nuclear Information System (INIS)

    Kothari, K.; Pillai, M.R.A.

    1994-01-01

    Preparation and purification of radioiodinated progesterone derivatives for the development of a radioimmunoassay of progesterone is described. Two procedures have been standardized for preparing radioiodinated progesterone conjugate. In the first procedure 125 I labeled histamine was conjugated to progesterone 11 α hemisuccinate by the mixed anhydride method. In the second procedure, tyrosyl methyl ester was conjugated to progesterone 11 α hemisuccinate and iodination of the conjugate was carried out. Purification of the iodinated products was carried out by solvent extraction and thin layer chromatography techniques. The radiochemical purity of the tracers prepared by both methods were more than 95%. Labeled progesterone derivatives prepared were used for developing a radioimmunoassay procedure. The non-specific binding of the tracer was about 2-3%, while up to 80% binding could be obtained in the presence of excess antibody. The radioiodinated tracer could be used up to four months in the assay. (author) 12 refs.; 2 figs.; 2 tabs

  4. Preparative isolation and purification of theaflavins and catechins by high-speed countercurrent chromatography.

    Science.gov (United States)

    Wang, Kunbo; Liu, Zhonghua; Huang, Jian-an; Dong, Xinrong; Song, Lubing; Pan, Yu; liu, Fang

    2008-05-15

    High-speed countercurrent chromatography (HSCCC) has been applied for the separation of theaflavins and catechins. The HSCCC run was carried out with a two-phase solvent system composed of hexane-ethyl acetate-methanol-water-acetic acid (1:5:1:5:0.25, v/v) by eluting the lower aqueous phase at 2 ml/min at 700 rpm. The results indicated that pure theaflavin, theaflavins-3-gallate, theaflavins-3'-gallate and theaflavin-3,3'-digallate could be obtained from crude theaflavins sample and black tea. The structures of the isolated compounds were positively confirmed by (1)H NMR and (13)C NMR, MS analysis, HPLC data and TLC data. Meanwhile, catechins including epigallocatechin gallate, gallocatechin gallate, epicatechin gallate and epigallocatechin were isolated from the aqueous extract of green tea by using the same solvent system. This study developed a modified method combined with enrichment theaflavins method by using HSCCC for separation of four individual theaflavins, especially for better separation of theaflavins monogallates.

  5. Sample Preparation for Determination of Biological Thiols by Liquid Chromatography and Electromigration Techniques

    OpenAIRE

    Bald, Edward

    2004-01-01

    Wydrukowano z dostarczonych Wydawnictwu UŁ gotowych materiałów Majority of the bioanalytical or environmental methods do not use just one chromatografie or electrophoretic step, but rather involve several sample pretreatment steps which simplfy the matrix, and often preconcentrate and chemically modify the analytes. This work surveys typical procedures for sample preparation for most commonly analyzed biofluids with particular emphasis placed on chemical derivatization of su...

  6. Recent trends in sorption-based sample preparation and liquid chromatography techniques for food analysis.

    Science.gov (United States)

    V Soares Maciel, Edvaldo; de Toffoli, Ana Lúcia; Lanças, Fernando Mauro

    2018-04-20

    The accelerated rising of the world's population increased the consumption of food, thus demanding more rigors in the control of residue and contaminants in food-based products marketed for human consumption. In view of the complexity of most food matrices, including fruits, vegetables, different types of meat, beverages, among others, a sample preparation step is important to provide more reliable results when combined with HPLC separations. An adequate sample preparation step before the chromatographic analysis is mandatory in obtaining higher precision and accuracy in order to improve the extraction of the target analytes, one of the priorities in analytical chemistry. The recent discovery of new materials such as ionic liquids, graphene-derived materials, molecularly imprinted polymers, restricted access media, magnetic nanoparticles, and carbonaceous nanomaterials, provided high sensitivity and selectivity results in an extensive variety of applications. These materials, as well as their several possible combinations, have been demonstrated to be highly appropriate for the extraction of different analytes in complex samples such as food products. The main characteristics and application of these new materials in food analysis will be presented and discussed in this paper. Another topic discussed in this review covers the main advantages and limitations of sample preparation microtechniques, as well as their off-line and on-line combination with HPLC for food analysis. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Cleaning of conveyor belt materials using ultrasound in a thin layer of water.

    Science.gov (United States)

    Axelsson, L; Holck, A; Rud, I; Samah, D; Tierce, P; Favre, M; Kure, C F

    2013-08-01

    Cleaning of conveyor belts in the food industry is imperative for preventing the buildup of microorganisms that can contaminate food. New technologies for decreasing water and energy consumption of cleaning systems are desired. Ultrasound can be used for cleaning a wide range of materials. Most commonly, baths containing fairly large amounts of water are used. One possibility to reduce water consumption is to use ultrasonic cavitation in a thin water film on a flat surface, like a conveyor belt. In order to test this possibility, a model system was set up, consisting of an ultrasound transducer/probe with a 70-mm-diameter flat bottom, operating at 19.8 kHz, and contaminated conveyor belt materials in the form of coupons covered with a thin layer of water or water with detergent. Ultrasound was then applied on the water surface at different power levels (from 46 to 260 W), exposure times (10 and 20 s), and distances (2 to 20 mm). The model was used to test two different belt materials with various contamination types, such as biofilms formed by bacteria in carbohydrate- or protein-fat-based soils, dried microorganisms (bacteria, yeasts, and mold spores), and allergens. Ultrasound treatment increased the reduction of bacteria and yeast by 1 to 2 log CFU under the most favorable conditions compared with water or water-detergent controls. The effect was dependent on the type of belt material, the power applied, the exposure time, and the distance between the probe and the belt coupon. Generally, dried microorganisms were more easily removed than biofilms. The effect on mold spores was variable and appeared to be species and material dependent. Spiked allergens were also efficiently removed by using ultrasound. The results in this study pave the way for new cleaning designs for flat conveyor belts, with possibilities for savings of water, detergent, and energy consumption.

  8. An empirical model to predict infield thin layer drying rate of cut switchgrass

    International Nuclear Information System (INIS)

    Khanchi, A.; Jones, C.L.; Sharma, B.; Huhnke, R.L.; Weckler, P.; Maness, N.O.

    2013-01-01

    A series of 62 thin layer drying experiments were conducted to evaluate the effect of solar radiation, vapor pressure deficit and wind speed on drying rate of switchgrass. An environmental chamber was fabricated that can simulate field drying conditions. An empirical drying model based on maturity stage of switchgrass was also developed during the study. It was observed that solar radiation was the most significant factor in improving the drying rate of switchgrass at seed shattering and seed shattered maturity stage. Therefore, drying switchgrass in wide swath to intercept the maximum amount of radiation at these stages of maturity is recommended. Moreover, it was observed that under low radiation intensity conditions, wind speed helps to improve the drying rate of switchgrass. Field operations such as raking or turning of the windrows are recommended to improve air circulation within a swath on cloudy days. Additionally, it was found that the effect of individual weather parameters on the drying rate of switchgrass was dependent on maturity stage. Vapor pressure deficit was strongly correlated with the drying rate during seed development stage whereas, vapor pressure deficit was weakly correlated during seed shattering and seed shattered stage. These findings suggest the importance of using separate drying rate models for each maturity stage of switchgrass. The empirical models developed in this study can predict the drying time of switchgrass based on the forecasted weather conditions so that the appropriate decisions can be made. -- Highlights: • An environmental chamber was developed in the present study to simulate field drying conditions. • An empirical model was developed that can estimate drying rate of switchgrass based on forecasted weather conditions. • Separate equations were developed based on maturity stage of switchgrass. • Designed environmental chamber can be used to evaluate the effect of other parameters that affect drying of crops

  9. Evaluation of some thin-layer drying models of persimmon slices (Diospyros kaki L.)

    International Nuclear Information System (INIS)

    Doymaz, İbrahim

    2012-01-01

    Highlights: ► In this study, convective drying (50–70 °C) was applied as a preservation technology for persimmon slices. ► The highest drying and rehydration rates obtained with blanched slices. ► The Midilli et al., Page and Weibull models were determined as the suitable models. ► Effective moisture diffusivity, diffusivity constant and activation energy for drying process were determined. - Abstract: The effect of blanching and drying temperature (50, 60 and 70 °C) on drying kinetics and rehydration ratio of persimmons under hot-air drying was investigated. It was observed that both the drying temperature and blanching affected the drying time. The shortest drying times and highest rehydration ratios were obtained from blanched samples. Six thin-layer drying models were evaluated in the kinetics research. The fit quality of the proposed models was evaluated by using the determination of coefficient (R 2 ), reduced chi-square (χ 2 ) and root means square error (RMSE). The Midilli et al., Page and Weibull models showed a better fit to experimental drying data as compared to other models. Effective moisture diffusivity (D eff ) ranged from 7.05 × 10 −11 to 2.34 × 10 −10 m 2 /s calculated using the Fick’s second law. The activation energies of blanched and control samples determined from slope of the Arrhenius plot, ln(D eff ) versus 1/(T + 273.15), was 30.64 and 43.26 kJ/mol, respectively.

  10. Assessment of doses caused by electrons in thin layers of tissue-equivalent materials, using MCNP.

    Science.gov (United States)

    Heide, Bernd

    2013-10-01

    Absorbed doses caused by electron irradiation were calculated with Monte Carlo N-Particle transport code (MCNP) for thin layers of tissue-equivalent materials. The layers were so thin that the calculation of energy deposition was on the border of the scope of MCNP. Therefore, in this article application of three different methods of calculation of energy deposition is discussed. This was done by means of two scenarios: in the first one, electrons were emitted from the centre of a sphere of water and also recorded in that sphere; and in the second, an irradiation with the PTB Secondary Standard BSS2 was modelled, where electrons were emitted from an (90)Sr/(90)Y area source and recorded inside a cuboid phantom made of tissue-equivalent material. The speed and accuracy of the different methods were of interest. While a significant difference in accuracy was visible for one method in the first scenario, the difference in accuracy of the three methods was insignificant for the second one. Considerable differences in speed were found for both scenarios. In order to demonstrate the need for calculating the dose in thin small zones, a third scenario was constructed and simulated as well. The third scenario was nearly equal to the second one, but a pike of lead was assumed to be inside the phantom in addition. A dose enhancement (caused by the pike of lead) of ∼113 % was recorded for a thin hollow cylinder at a depth of 0.007 cm, which the basal-skin layer is referred to in particular. Dose enhancements between 68 and 88 % were found for a slab with a radius of 0.09 cm for all depths. All dose enhancements were hardly noticeable for a slab with a cross-sectional area of 1 cm(2), which is usually applied to operational radiation protection.

  11. Amino Acid Composition, Urease Activity and Trypsin Inhibitor Activity after Toasting of Soybean in Thick and Thin Layer

    OpenAIRE

    Krička, Tajana; Jurišić, Vanja; Voća, Neven; Ćurić, Duška; Brlek Savić, Tea; Matin, Ana

    2009-01-01

    The objective of this study was to determine amino acid content, urease activity and trypsin inhibitor activity in soybean grain for polygastric animals’ feed aft er toasting with the aim to introduce thick layer in toasting technology. Hence, soybean was toasted both in thick and thin layer at 130 oC during 10 minutes. In order to properly monitor the technological process of soybean thermal processing, it was necessary to study crude protein content, urease activity, trypsin inhibitor activ...

  12. Electrochemical studies of iron/carbonates system applied to the formation of thin layers of siderite on inert substrates

    International Nuclear Information System (INIS)

    Ithurbide, A.; Peulon, S.; Mandin, Ph.; Beaucaire, C.; Chausse, A.

    2007-01-01

    In order to understand the complex mechanisms of the reactions occurring, a methodology is developed. It is based on the use of compounds electrodeposited under the form of thin layers and which are used then as electrodes to study their interactions with the toxic species. It is in this framework that is studied the electrodeposition of siderite on inert substrates. At first, have been studied iron electrochemical systems in carbonated solutions. These studies have been carried out with classical electrochemical methods (cyclic voltametry, amperometry) coupled to in-situ measurements: quartz microbalance, pH. Different compounds have been obtained under the form of homogeneous and adherent thin layers. The analyses of these depositions, by different ex-situ characterizations (XRD, IR, SEM, EDS..) have revealed particularly the presence of siderite. Then, the influence of several experimental parameters (substrate, potential, medium composition, temperature) on the characteristics of siderite thin layers has been studied. From these experimental results, models have been proposed. (O.M.)

  13. A method of sample preparation for N15 determination in amino acids separated by paper chromatography

    International Nuclear Information System (INIS)

    Secer, M.

    1988-01-01

    The amino acids separated with two dimensional paper chromatography were isolated in two ways which make their 15 N determination possible 1) After developing the spots of chromatograms with ninhydrin they were cut out and shaken 30' with 2 ml dist. H 2 O. To destroy the ninhydrin-NH 3 colour complex, the extraction solution was heated in boiling waterbath for 10' and then 0.5 ml 2 N HCl was added to the solution and continued to heat for further 10'. For the 15 N determination of amino acids by emissionspectrometer this colour complex must be destroyed completely. It was reached with adding 2 ml 30% H 2 O 2 to the solution and heating it 5' in 100 0 C waterbath. After the evaporation of colourless solution under IR-lamp at 70 0 C, the white powder was dissolved with 50 ul dist. H 2 O and centrifuged 10'. The clear supernatant was used to gain N 2 gas by the CuO/CaO combustion. N 2 gas is necessary for the 15 N/ 14 N ratio determination by emissionsspectrometer. 2) In the second way, the destroying of ninhydrin-NH 3 colour complex was easier and quicker this way the spots were eluted (extracted) with 50% alcohol and 30% H 2O2 with 1:1 ratio. After shaking the solution 30', it turns quite colourless. It means that the ninhydrin-NH 3 colour complex was completely destroyed. Further works have been done as described in the first way. We have found out that one amino acid should have 10-20 ug N in it to assess the 15 N enrichment. In order to attain this quantity of N for certain amino acids, the spots of three separately run chromatograms were combined

  14. Preparation of organic monolithic columns in polytetrafluoroethylene tubes for reversed-phase liquid chromatography

    International Nuclear Information System (INIS)

    Catalá-Icardo, M.; Torres-Cartas, S.; Meseguer-Lloret, S.; Gómez-Benito, C.; Carrasco-Correa, E.; Simó-Alfonso, E.F.; Ramis-Ramos, G.; Herrero-Martínez, J.M.

    2017-01-01

    In this work, a method for the preparation and anchoring of polymeric monoliths in a polytetrafluoroethylene (PTFE) tubing as a column housing for microbore HPLC is described. In order to assure a covalent attachment of the monolith to the inner wall of the PTFE tube, a two-step procedure was developed. Two surface etching reagents, a commercial sodium naphthalene solution (Fluoroetch"®), or mixtures of H_2O_2 and H_2SO_4, were tried and compared. Then, the obtained hydroxyl groups on the PTFE surface were modified by methacryloylation. Attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy and scanning electron microscopy (SEM) confirmed the successful modification of the tubing wall and the stable anchorage of monolith to the wall, respectively. Special emphasis was also put on the reduction of the unwanted effects of shrinking of monolith during polymerization, by using an external proper mold and by selecting the adequate monomers in order to increase the flexibility of the polymer. Poly(glycidyl methacrylate-co-divinylbenzene) monoliths were in situ synthesized by thermal polymerization within the confines of surface-vinylized PTFE tubes. The modified PTFE tubing tightly held the monolith, and the monolithic column exhibited good pressure resistance up to 20 MPa. The column performance was also evaluated via the isocratic separation of a series of alkylbenzenes in the reversed-phase mode. The optimized monolithic columns gave plate heights ranged between 70 and 80 μm. The resulting monoliths were also satisfactorily applied to the separation of proteins. - Highlights: • Successful surface etching of PTFE inner wall tubing was done. • The modified PTFE support was next methacryloylated with GMA. • Organic polymeric monolith was in situ prepared in the functionalized PTFE tube. • The monolithic columns gave suitable pressure resistance and separation of proteins.

  15. Preparation of organic monolithic columns in polytetrafluoroethylene tubes for reversed-phase liquid chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Catalá-Icardo, M., E-mail: mocaic@qim.upv.es [Research Institute for Integrated Management of Coastal Areas, Universitat Politècnica de València, Paranimf 1, 46730, Grao de Gandía, Valencia (Spain); Torres-Cartas, S.; Meseguer-Lloret, S.; Gómez-Benito, C. [Research Institute for Integrated Management of Coastal Areas, Universitat Politècnica de València, Paranimf 1, 46730, Grao de Gandía, Valencia (Spain); Carrasco-Correa, E.; Simó-Alfonso, E.F.; Ramis-Ramos, G. [Department of Analytical Chemistry, Universitat de València, Dr. Moliner 50, 46100, Burjassot, Valencia (Spain); Herrero-Martínez, J.M., E-mail: jmherrer@uv.es [Department of Analytical Chemistry, Universitat de València, Dr. Moliner 50, 46100, Burjassot, Valencia (Spain)

    2017-04-01

    In this work, a method for the preparation and anchoring of polymeric monoliths in a polytetrafluoroethylene (PTFE) tubing as a column housing for microbore HPLC is described. In order to assure a covalent attachment of the monolith to the inner wall of the PTFE tube, a two-step procedure was developed. Two surface etching reagents, a commercial sodium naphthalene solution (Fluoroetch{sup ®}), or mixtures of H{sub 2}O{sub 2} and H{sub 2}SO{sub 4}, were tried and compared. Then, the obtained hydroxyl groups on the PTFE surface were modified by methacryloylation. Attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy and scanning electron microscopy (SEM) confirmed the successful modification of the tubing wall and the stable anchorage of monolith to the wall, respectively. Special emphasis was also put on the reduction of the unwanted effects of shrinking of monolith during polymerization, by using an external proper mold and by selecting the adequate monomers in order to increase the flexibility of the polymer. Poly(glycidyl methacrylate-co-divinylbenzene) monoliths were in situ synthesized by thermal polymerization within the confines of surface-vinylized PTFE tubes. The modified PTFE tubing tightly held the monolith, and the monolithic column exhibited good pressure resistance up to 20 MPa. The column performance was also evaluated via the isocratic separation of a series of alkylbenzenes in the reversed-phase mode. The optimized monolithic columns gave plate heights ranged between 70 and 80 μm. The resulting monoliths were also satisfactorily applied to the separation of proteins. - Highlights: • Successful surface etching of PTFE inner wall tubing was done. • The modified PTFE support was next methacryloylated with GMA. • Organic polymeric monolith was in situ prepared in the functionalized PTFE tube. • The monolithic columns gave suitable pressure resistance and separation of proteins.

  16. Transesterification double step process for biodiesel preparation and its chromatographic characterization: oils and fats in practical organic chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Diogo Mueller de; Ongaratto, Diego Paulo; Fontoura, Luiz Antonio Mazzini; Naciuk, Fabricio Fredo; Santos, Vinicius Oliveira Batista dos; Kunz, Jessica Danieli; Marques, Marcelo Volpatto, E-mail: lmazzini@uol.com.br [Departamento de Engenharia de Processos, Fundacao de Ciencia e Tecnologia, Porto Alegre, RS (Brazil); Curso de Quimica, Universidade Luterana do Brasil, Canoas RS (Brazil); Souza, Alexander Ossanes de; Pereira, Claudio Martin Pereira de [Centro de Ciencias Quimicas, Farmaceuticas e de Alimentos, Universidade Federal de Pelotas, RS (Brazil); Samios, Dimitrios [Departamento de Fisico-Quimica, Instituto de Quimica, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS (Brazil)

    2013-09-01

    Methanolic transesterification of oils and fats was carried out in a two steps procedure, under basic and acidic catalysis. Palm, soybean, canola, corn, rice, grape seed, sunflower, peanut, pequi and olive oils, besides tallow and lard were used as feedstock. Specific gravity, relative viscosity, thin layer chromatography and gas chromatography were used to characterize the biodiesel. Biodiesel was obtained in high yield and purity. Results were used to discuss the following key-concepts: 1 - triglycerides, composition and properties; 2 - nucleophilic acyl substitution under basic and acid conditions, 3 - thin layer chromatography, 4 - as chromatography and its quantitative methods. (author)

  17. Transesterification double step process for biodiesel preparation and its chromatographic characterization: oils and fats in practical organic chemistry

    International Nuclear Information System (INIS)

    Oliveira, Diogo Müller de; Ongaratto, Diego Paulo; Fontoura, Luiz Antonio Mazzini; Naciuk, Fabrício Fredo; Santos, Vinícius Oliveira Batista dos; Kunz, Jéssica Danieli; Marques, Marcelo Volpatto; Souza, Alexander Ossanes de; Pereira, Claudio Martin Pereira de; Samios, Dimitrios

    2013-01-01

    Methanolic transesterification of oils and fats was carried out in a two steps procedure, under basic and acidic catalysis. Palm, soybean, canola, corn, rice, grape seed, sunflower, peanut, pequi and olive oils, besides tallow and lard were used as feedstock. Specific gravity, relative viscosity, thin layer chromatography and gas chromatography were used to characterize the biodiesel. Biodiesel was obtained in high yield and purity. Results were used to discuss the following key-concepts: 1 – triglycerides, composition and properties; 2 – nucleophilic acyl substitution under basic and acid conditions, 3 – thin layer chromatography, 4 – as chromatography and its quantitative methods. (author)

  18. The effect of selected preparation variables on the radiochemical purity of 99mTc-EDDA-HYNIC-TOC

    International Nuclear Information System (INIS)

    Betuel Tasdelen

    2011-01-01

    [ 99m Tc-EDDA-HYNIC-D-Phe 1 , Tyr 3 ]-Ocreotide ( 99m Tc-EDDA-HYNIC-TOC) increasingly emerges to be an alternative tool for somatostatin receptor (SSTR) scintigraphy of neuroendocrine tumours. The high quality of this radiopharmaceutical and its uniformity are very important facts for application of this preparation in clinical practice. Various factors may influence the radiochemical purity (RCP) of certain reagent kits. Some of these include the amount of activity added to the reagent kit, heating time and the age of the formulated kit. The effect of these factors on RCP of 99m Tc-EDDA-HYNIC-TOC has been investigated using high performance liquid chromatography (HPLC) and instant thin layer chromatography (ITLC). (author)

  19. Microfabrication, separations, and detection by mass spectrometry on ultrathin-layer chromatography plates prepared via the low-pressure chemical vapor deposition of silicon nitride onto carbon nanotube templates.

    Science.gov (United States)

    Kanyal, Supriya S; Häbe, Tim T; Cushman, Cody V; Dhunna, Manan; Roychowdhury, Tuhin; Farnsworth, Paul B; Morlock, Gertrud E; Linford, Matthew R

    2015-07-24

    Microfabrication of ultrathin-layer chromatography (UTLC) plates via conformal deposition of silicon nitride by low-pressure chemical vapor deposition onto patterned carbon nanotube (CNT) scaffolds was demonstrated. After removal of the CNTs and hydroxylation, the resulting UTLC phase showed no expansion or distortion of their microfeatures and the absence/reduction of remaining nitrogenic species. Developing time of a mixture of lipophilic dyes on this UTLC plates was 86% shorter than on high-performance thin-layer chromatography (HPTLC) plates. A water-soluble food dye mixture was also separated resulting in low band broadening and reduced developing time compared to HPTLC. For the latter example, mobile phase optimization on a single UTLC plate consisted of 14 developments with different mobile phases, each preceded by a plate prewashing step. The same plate was again reused for additional 11 separations under varying conditions resulting in a development procedure with a mean separation efficiency of 233,000theoretical plates/m and a reduced mobile phase consumption of only 400μL. This repeated use proved the physical robustness of the ultrathin layer and its resistance to damage. The layer was highly suited for hyphenation to ambient mass spectrometry, including desorption electrospray ionization (DESI) mass spectrometry imaging and direct analysis in real time (DART) mass spectrometry. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. [Preparation and evaluation of stationary phase of high performance liquid chromatography for the separation of basic solutes].

    Science.gov (United States)

    Wang, P; Wang, J; Cong, R; Dong, B

    1997-05-01

    A bonded phase for high performance liquid chromatography (HPLC) has been prepared by the new reaction between silica and silicon ether. The ether was synthesized from alkylchlorosilane and pentane-2,4-dione in the presence of imidazole under inert conditions by using anhydrous tetrahydrofuran as solvent. The bonded phase thus obtained was characterized by elemental analysis, diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy and HPLC evaluation. The carbon content was 9.4% and the surface coverage almost attained 3.0micromol/m2 without end-capping. The silanol absorption peaks of the product cannot be observed from the DRIFT spectrum, which revealed that the silanization reaction proceeded thoroughly. The basic solutes, such as aniline, o-toluidine, p-toluidine, N,N-dimethylaniline and pyridine were used as the probe solutes to examine their interaction with the residual silanols on the surface of the products. No buffer or salt was used in the mobile phase for these experiments. In comparison with an acidic solute, such as, phenol, basic aniline eluted in front of phenol, and the ratio of asymmetry of aniline peak to that of the phenol peak was 1.1. Furthermore the relative k' value of p-toluidine to that of o-toluidine was also 1.1. All the results showed that the stationary phase has better quality and reproducibility and can be used for the separation of basic solutes efficiently.

  1. Food Sample Preparation for the Determination of Sulfonamides by High-Performance Liquid Chromatography: State-of-the-Art

    Directory of Open Access Journals (Sweden)

    Dimitrios Bitas

    2018-06-01

    Full Text Available Antibiotics are a common practice in veterinary medicine, mainly for therapeutic purposes. Sectors of application include livestock farming, aquacultures, and bee-keeping, where bacterial infections are frequent and can be economically damaging. However, antibiotics are usually administered in sub-therapeutic doses as prophylactic and growth promoting agents. Due to their excessive use, antibiotic residues can be present in foods of animal origin, which include meat, fish, milk, eggs, and honey, posing health risks to consumers. For this reason, authorities have set maximum residue limits (MRLs of certain antibiotics in food matrices, while analytical methods for their determination have been developed. This work focuses on antibiotic extraction and determination, part of which was presented at the “1st Conference in Chemistry for Graduate, Postgraduate Students and PhD Candidates at the Aristotle University of Thessaloniki”. Taking a step further, this paper is a review of the most recent sample preparation protocols applied for the extraction of sulfonamide antibiotics from food samples and their determination with high-performance liquid chromatography (HPLC, covering a five-year period.

  2. Isolation of Methoxyfuranocoumarins From Ammi majus by Centrifugal Partition Chromatography.

    Science.gov (United States)

    Bartnik, Magdalena; Mazurek, Anna Katarzyna

    2016-01-01

    Pure methoxyfuranocoumarins were isolated from Ammi majus L. by use of low-pressure column chromatography (LPCC) followed by centrifugal partition chromatography (CPC). The concentrated petroleum ether extract from fruits of A. majus was fractionated on a silica gel column using a gradient of ethyl acetate in dichloromethane (0-80%, v/v). Coumarin-rich fractions were analyzed by thin-layer chromatography (TLC) and high-performance liquid chromatography with diode array detection (HPLC/DAD). Xanthotoxin (8-MOP) and isopimpinellin (isoP), structurally similar compounds, were isolated in one fraction (FR6). To avoid multistep and long-lasting TLC preparation, optimization of CPC conditions has been performed. In one run, an effective separation of 8-MOP and isoP was achieved. The two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water (10 : 8 : 10 : 9; v/v) in an ascending mode (the aqueous phase was a stationary phase, and the organic phase was a mobile phase), with flow rate 3 mL/min and rotation speed 1,600 r.p.m., was used. The identification and high purities of isolated 8-MOP (98.7%) and isoP (100%) were confirmed by HPLC/DAD assay, when compared with standards. The developed CPC method could be applied to the effective isolation of 8-MOP and isoP from plant extracts. The high purity of obtained compounds makes possible further exploitation of these components in biological studies. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  3. Ascorbic acid surface modified TiO2-thin layers as a fully integrated analysis system for visual simultaneous detection of organophosphorus pesticides

    Science.gov (United States)

    Li, Shunxing; Liang, Wenjie; Zheng, Fengying; Lin, Xiaofeng; Cai, Jiabai

    2014-11-01

    TiO2 photocatalysis and colorimetric detection are coupled with thin layer chromatography (TLC) for the first time to develop a fully integrated analysis system. Titania@polystyrene hybrid microspheres were surface modified with ascorbic acid, denoted AA-TiO2@PS, and used as the stationary phase for TLC. Because the affinity between AA-TiO2@PS and organophosphorus pesticides (OPs) was different for different species of OPs (including chlopyrifos, malathion, parathion, parathion-methyl, and methamidophos), OPs could be separated simultaneously by the mobile phase in 12.0 min with different Rf values. After surface modification, the UV-vis wavelength response range of AA-TiO2@PS was expanded to 650 nm. Under visible-light irradiation, all of the OPs could be photodegraded to PO43- in 25.0 min. Based on the chromogenic reaction between PO43- and chromogenic agents (ammonium molybdate and ascorbic acid), OPs were quantified from color intensity images using a scanner in conjunction with image processing software. So, AA-TiO2@PS was respectively used as the stationary phase of TLC for efficient separation of OPs, as a photocatalyst for species transformation of phosphorus, and as a colorimetric probe for on-field simultaneous visual detection of OPs in natural water. Linear calibration curves for each OP ranged from 19.3 nmol P L-1 to 2.30 μmol P L-1. This integrated analysis system was simple, inexpensive, easy to operate, and sensitive.TiO2 photocatalysis and colorimetric detection are coupled with thin layer chromatography (TLC) for the first time to develop a fully integrated analysis system. Titania@polystyrene hybrid microspheres were surface modified with ascorbic acid, denoted AA-TiO2@PS, and used as the stationary phase for TLC. Because the affinity between AA-TiO2@PS and organophosphorus pesticides (OPs) was different for different species of OPs (including chlopyrifos, malathion, parathion, parathion-methyl, and methamidophos), OPs could be separated

  4. Preparation of a novel dual-function strong cation exchange/hydrophobic interaction chromatography stationary phase for protein separation.

    Science.gov (United States)

    Zhao, Kailou; Yang, Li; Wang, Xuejiao; Bai, Quan; Yang, Fan; Wang, Fei

    2012-08-30

    We have explored a novel dual-function stationary phase which combines both strong cation exchange (SCX) and hydrophobic interaction chromatography (HIC) characteristics. The novel dual-function stationary phase is based on porous and spherical silica gel functionalized with ligand containing sulfonic and benzyl groups capable of electrostatic and hydrophobic interaction functionalities, which displays HIC character in a high salt concentration, and IEC character in a low salt concentration in mobile phase employed. As a result, it can be employed to separate proteins with SCX and HIC modes, respectively. The resolution and selectivity of the dual-function stationary phase were evaluated under both HIC and SCX modes with standard proteins and can be comparable to that of conventional IEC and HIC columns. More than 96% of mass and bioactivity recoveries of proteins can be achieved in both HIC and SCX modes, respectively. The results indicated that the novel dual-function column could replace two individual SCX and HIC columns for protein separation. Mixed retention mechanism of proteins on this dual-function column based on stoichiometric displacement theory (SDT) in LC was investigated to find the optimal balance of the magnitude of electrostatic and hydrophobic interactions between protein and the ligand on the silica surface in order to obtain high resolution and selectivity for protein separation. In addition, the effects of the hydrophobicity of the ligand of the dual-function packings and pH of the mobile phase used on protein separation were also investigated in detail. The results show that the ligand with suitable hydrophobicity to match the electrostatic interaction is very important to prepare the dual-function stationary phase, and a better resolution and selectivity can be obtained at pH 6.5 in SCX mode. Therefore, the dual-function column can replace two individual SCX and HIC columns for protein separation and be used to set up two-dimensional liquid

  5. Controlled Zn-mediated grafting of thin layers of bipodal diazonium salt on gold and carbon substrates.

    Science.gov (United States)

    Torréns, Mabel; Ortiz, Mayreli; Turner, Anthony P F; Beni, Valerio; O'Sullivan, Ciara K

    2015-01-07

    A controlled, rapid, and potentiostat-free method has been developed for grafting the diazonium salt (3,5-bis(4-diazophenoxy)benzoic acid tetrafluoroborate (DCOOH)) on gold and carbon substrates, based on a Zn-mediated chemical dediazonation. The highly stable thin layer organic platforms obtained were characterized by cyclic voltammetry, AFM, impedance, XP, and Raman spectroscopies. A dediazonation mechanism based on radical formation is proposed. Finally, DCOOH was proved as a linker to an aminated electroactive probe. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Thin layer convective air drying of wild edible plant (Allium roseum) leaves: experimental kinetics, modeling and quality

    OpenAIRE

    Ben Haj Said, Leila; Najjaa, Hanen; Farhat, Abdelhamid; Neffati, Mohamed; Bellagha, Sihem

    2014-01-01

    The present study deals with the valorization of an edible spontaneous plant of the Tunisian arid areas: Allium roseum. This plant is traditionally used for therapeutic and culinary uses. Thin-layer drying behavior of Allium roseum leaves was investigated at 40, 50 and 60 °C drying air temperatures and 1 and l.5 m/s air velocity, in a convective dryer. The increase in air temperature significantly affected the moisture loss and reduced the drying time while air velocity was an insignificant f...

  7. Recent developments in wear measurements with the thin layer activation technique. Neuere Entwicklungen der Verschleissmesstechnik mit dem Verfahren der Duennschichtaktivierung

    Energy Technology Data Exchange (ETDEWEB)

    Kleinrahm, A.; Fehsenfeld, P. (Kernforschungszentrum Karlsruhe GmbH (Germany, F.R.). Inst. fuer Kernphysik 3)

    1989-01-01

    At the KfK's compact cyclotron an efficient serial radiation plant for the thin-layer activation of machine and plant components for industry and research was provided. By means of this fully automatic plant it is possible to carry out wear measurements on ceramic compositions, cermets and related hard materials. The further developed RTM activation and measuring technique was used for the investigation of the erosive and corrosive wear behaviour of pipelines and pump parts in liquid mediums with solid matter proportions, in the field of textile technology (knitting machines) and for the detection of material dislocations in the bearing surface of wheel-rail-tribo-systems. (DG).

  8. Diurnal changes of photosynthesis and growth of Arthrospira platensis cultured in a thin-layer cascade and an open pond

    Czech Academy of Sciences Publication Activity Database

    Benavides, A.M.S.; Ranglová, Karolína; Malapascua, José R.; Masojídek, Jiří; Torzillo, G.

    2017-01-01

    Roč. 28, DEC (2017), s. 48-56 ISSN 2211-9264 R&D Projects: GA MŠk(CZ) LO1416; GA MŠk EE2.3.30.0059 Grant - others:AV ČR(CZ) CNR-16-29 Program:Bilaterální spolupráce Institutional support: RVO:61388971 Keywords : Arthrospira platensis * Pond * Thin-layer cascade Subject RIV: EE - Microbiology, Virology OBOR OECD: Microbiology Impact factor: 3.994, year: 2016

  9. New on-line separation workflow of microbial metabolites via hyphenation of analytical and preparative comprehensive two-dimensional liquid chromatography.

    Science.gov (United States)

    Yan, Xia; Wang, Li-Juan; Wu, Zhen; Wu, Yun-Long; Liu, Xiu-Xiu; Chang, Fang-Rong; Fang, Mei-Juan; Qiu, Ying-Kun

    2016-10-15

    Microbial metabolites represent an important source of bioactive natural products, but always exhibit diverse of chemical structures or complicated chemical composition with low active ingredients content. Traditional separation methods rely mainly on off-line combination of open-column chromatography and preparative high performance liquid chromatography (HPLC). However, the multi-step and prolonged separation procedure might lead to exposure to oxygen and structural transformation of metabolites. In the present work, a new two-dimensional separation workflow for fast isolation and analysis of microbial metabolites from Chaetomium globosum SNSHI-5, a cytotoxic fungus derived from extreme environment. The advantage of this analytical comprehensive two-dimensional liquid chromatography (2D-LC) lies on its ability to analyze the composition of the metabolites, and to optimize the separation conditions for the preparative 2D-LC. Furthermore, gram scale preparative 2D-LC separation of the crude fungus extract could be performed on a medium-pressure liquid chromatograph×preparative high-performance liquid chromatography system, under the optimized condition. Interestingly, 12 cytochalasan derivatives, including two new compounds named cytoglobosin Ab (3) and isochaetoglobosin Db (8), were successfully obtained with high purity in a short period of time. The structures of the isolated metabolites were comprehensively characterized by HR ESI-MS and NMR. To be highlighted, this is the first report on the combination of analytical and preparative 2D-LC for the separation of microbial metabolites. The new workflow exhibited apparent advantages in separation efficiency and sample treatment capacity compared with conventional methods. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Combinative application of pH-zone-refining and conventional high-speed counter-current chromatography for preparative separation of caged polyprenylated xanthones from gamboge.

    Science.gov (United States)

    Xu, Min; Fu, Wenwei; Zhang, Baojun; Tan, Hongsheng; Xiu, Yanfeng; Xu, Hongxi

    2016-02-01

    An efficient method for the preparative separation of four structurally similar caged xanthones from the crude extracts of gamboge was established, which involves the combination of pH-zone-refining counter-current chromatography and conventional high-speed counter-current chromatography for the first time. pH-zone-refining counter-current chromatography was performed with the solvent system composed of n-hexane/ethyl acetate/methanol/water (7:3:8:2, v/v/v/v), where 0.1% trifluoroacetic acid was added to the upper organic stationary phase as a retainer and 0.03% triethylamine was added to the aqueous mobile phase as an eluter. From 3.157 g of the crude extract, 1.134 g of gambogic acid, 180.5 mg of gambogenic acid and 572.9 mg of a mixture of two other caged polyprenylated xanthones were obtained. The mixture was further separated by conventional high-speed counter-current chromatography with a solvent system composed of n-hexane/ethyl acetate/methanol/water (5:5:10:5, v/v/v/v) and n-hexane/methyl tert-butyl ether/acetonitrile/water (8:2:6:4,v/v/v/v), yielding 11.6 mg of isogambogenic acid and 10.4 mg of β-morellic acid from 218.0 mg of the mixture, respectively. The purities of all four of the compounds were over 95%, as determined by high-performance liquid chromatography, and the chemical structures of the four compounds were confirmed by electrospray ionization mass spectrometry and NMR spectroscopy. The combinative application of pH-zone-refining counter-current chromatography and conventional high-speed counter-current chromatography shows great advantages in isolating and enriching the caged polyprenylated xanthones. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Preparative isolation and purification of hainanmurpanin, meranzin, and phebalosin from leaves of Murraya exotica L. using supercritical fluid extraction combined with consecutive high-speed countercurrent chromatography.

    Science.gov (United States)

    Yan, Rongwei; Shen, Jie; Liu, Xiaojing; Zou, Yong; Xu, Xinjun

    2018-05-01

    The objective of this study was to develop a consecutive preparation method for the isolation and purification of hainanmurpanin, meranzin, and phebalosin from leaves of Murraya exotica L. The process involved supercritical fluid extraction with CO 2 , solvent extraction, and two-step high-speed countercurrent chromatography. Pressure, temperature, and the volume of entrainer were optimized as 27 MPa, 52°C, and 60 mL by response surface methodology in supercritical fluid extraction with CO 2 , and the yield of the crude extracts was 7.91 g from 100 g of leaves. Subsequently, 80% methanol/water was used to extract and condense the three compounds from the crude extracts, and 4.23 g of methanol/water extracts was obtained. Then, a two-step high-speed countercurrent chromatography procedure was developed for the isolation of the three target compounds from methanol/water extracts, including conventional high-speed countercurrent chromatography for further enrichment and consecutive high-speed countercurrent chromatography for purification. The yield of concentrates from high-speed countercurrent chromatography was 2.50 g from 4.23 g of methanol/water extracts. Finally, the consecutive high-speed countercurrent chromatography produced 103.2 mg of hainanmurpanin, 244.7 mg of meranzin, and 255.4 mg of phebalosin with purities up to 97.66, 99.36, and 98.64%, respectively, from 900 mg of high-speed countercurrent chromatography concentrates in one run of three consecutive sample loadings without exchanging a solvent system. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Depth profiling of fluorine-doped diamond-like carbon (F-DLC) film: Localized fluorine in the top-most thin layer can enhance the non-thrombogenic properties of F-DLC

    Energy Technology Data Exchange (ETDEWEB)

    Hasebe, Terumitsu [Center for Science of Environment, Resources and Energy, Keio University Faculty of Science and Technology, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522 (Japan); Department of Radiology, Tachikawa Hospital, 4-2-22, Nishiki-cho, Tachikawa, Tokyo 190-8531 (Japan)], E-mail: teru_hasebe@hotmail.com; Nagashima, So [Center for Science of Environment, Resources and Energy, Keio University Faculty of Science and Technology, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522 (Japan); Kamijo, Aki [Department of Transfusion Medicine, the University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655 (Japan); Yoshimura, Taichi; Ishimaru, Tetsuya; Yoshimoto, Yukihiro; Yohena, Satoshi; Kodama, Hideyuki; Hotta, Atsushi [Center for Science of Environment, Resources and Energy, Keio University Faculty of Science and Technology, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522 (Japan); Takahashi, Koki [Department of Transfusion Medicine, the University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655 (Japan); Suzuki, Tetsuya [Center for Science of Environment, Resources and Energy, Keio University Faculty of Science and Technology, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522 (Japan)

    2007-12-03

    Fluorine-doped diamond-like carbon (F-DLC) has recently drawn a great deal of attention as a more non-thrombogenic coating than conventional DLC for blood-contacting medical devices. We conducted quantitative depth profiling of F-DLC film by X-ray photoelectron spectroscopy (XPS) in order to elucidate the effects of fluorine and fluorine distribution in F-DLC film in connection with the prevention of surface blood adhesion. F-DLC films were prepared on silicon substrates using the radio frequency plasma enhanced chemical vapor deposition method, and the thickness of films was {approx} 50 nm. 50-nm-thick F-DLC film samples were etched at 10-nm thickness intervals using argon plasma, and each surface was examined by XPS. Thereafter, each etched film layer was incubated with platelet-rich plasma isolated from human whole blood, and the platelet-covered area per unit area was evaluated for each surface. XPS spectra showed the localization of doped fluorine in the top-most thin layer of the film. Platelet-covered areas represented progressively larger portions of the surfaces of deeper etched layers, corresponding to the decreasing fluorine content in such sample surfaces. These results indicate that the localized fluorine in the top-most thin layer is one of the key factors in the promotion of the non-thrombogenicity of F-DLC film.

  13. Preparation and Characterization of a Polymeric Monolithic Column for Use in High-Performance Liquid Chromatography (HPLC)

    Science.gov (United States)

    Bindis, Michael P.; Bretz, Stacey Lowery; Danielson, Neil D.

    2011-01-01

    The high-performance liquid chromatography (HPLC) experiment, most often done in the undergraduate analytical instrumentation laboratory course, generally illustrates reversed-phase chromatography using a commercial C[subscript]18 silica column. To avoid the expense of periodic column replacement and introduce a choice of columns with different…

  14. Preparation and high-performance liquid chromatography of 3'-phosphoadenosine-5'-phospho[35S]sulfate with a predetermined specific activity

    International Nuclear Information System (INIS)

    Delfert, D.M.; Conrad, H.E.

    1985-01-01

    3'-Phosphoadenosine-5'-phospho[35S]sulfate (PAP 35 S) was prepared by incubating ATP and carrier-free H 2 ( 35 )SO 4 with a 100,000g supernatant fraction prepared from chick embryo chondrocytes. The product was partially purified by paper electrophoresis and mixed with unlabeled PAPS to give a solution of PAP 35 S with a specific activity and a concentration approximating those required for the desired metabolic studies. The product was analyzed by high-performance liquid chromatography on an anion-exchange column to determine the proportion of the 35 SO 4 cpm and A260 material found in the PAPS and other contaminating nucleotides. The PAP 35 S was purified further by preparative high-performance liquid chromatography. The exact specific activity of the PAP 35 S was then determined by using this PAP 35 S preparation as the SO 4 donor in a sulfotransferase reaction using a microsomal preparation from the chick embryo chondrocytes as the enzyme and an 3 H-labeled oligosaccharide as the SO 4 acceptor. The sulfated oligosaccharide was then isolated and the number of 3 H and 35 SO 4 counts per minute in this product were used to calculate the specific activity of the donor. The features of this generally useful approach for preparing PAP 35 S of any desired specific activity and concentration are discussed

  15. Simultaneous determination of atorvastatin calcium and ramipril in capsule dosage forms by high-performance liquid chromatography and high-performance thin layer chromatography.

    Science.gov (United States)

    Panchal, Hiral J; Suhagia, Bhanubhai N

    2010-01-01

    Two simple and accurate methods to determine atorvastatin calcium and ramipril in capsule dosage forms were developed and validated using HPLC and HPTLC. The HPLC separation was achieved on a Phenomenex Luna C18 column (250 x 4.6 mm id, 5 microm) in the isocratic mode using 0.1% phosphoric acid-acetonitrile (38 + 62, v/v), pH 3.5 +/- 0.05, mobile phase at a flow rate of 1 ml/min. The retention times were 6.42 and 2.86 min for atorvastatin calcium and ramipril, respectively. Quantification was achieved with a photodiode array detector set at 210 nm over the concentration range of 0.5-5 microg/mL for each, with mean recoveries (at three concentration levels) of 100.06 +/- 0.49% and 99.95 +/- 0.63% RSD for atorvastatin calcium and ramipril, respectively. The HPTLC separation was achieved on silica gel 60 F254 HPTLC plates using methanol-benzene-glacial acetic acid (19.6 + 80.0 + 0.4, v/v/v) as the mobile phase. The Rf values were 0.40 and 0.20 for atorvastatin calcium and ramipril, respectively. Quantification was achieved with UV densitometry at 210 nm over the concentration range of 50-500 ng/spot for each, with mean recoveries (at three concentration levels) of 99.98 +/- 0.75% and 99.87 +/- 0.83% RSD for atorvastatin calcium and ramipril, respectively. Both methods were validated according to International Conference on Harmonization guidelines and found to be simple, specific, accurate, precise, and robust. The mean assay percentages for atorvastatin calcium and ramipril were 99.90 and 99.55% for HPLC and 99.91 and 99.47% for HPTLC, respectively. The methods were successfully applied for the determination of atorvastatin calcium and ramipril in capsule dosage forms without any interference from common excipients.

  16. Determination of piroxicam in pharmaceutical preparations by ultraviolet direct spectrophotometry, ultraviolet difference spectrophotometry and high performance liquid chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Hackmann, E.R.M.; Santos Gianotto, E.A. dos; Miritello Santoro, M.I.R. (Universidade de Sao Paulo (Brazil))

    1993-02-01

    Piroxicam in pharmaceutical preparations (capsules (C), tablets (T), oral drops (OD), suppositories (S) and simulated sample (SS)) was determined by UV direct spectrophotometry (UVS) at 333 nm, by UV difference spectrophotometry (UVDS) at 327 nm, and in C and T, by high performance liquid chromatography (HPLC). For UVS, Beer's law was obeyed in the range 3.0-8.5 [mu]g/mL. The coefficient of correlation (CC), absolute precision (AP) and relative precision (RP) were 0.9999, 0.02 and 0.33%, respectively. The coefficient of variation (CV) for C, T, OD, S and SS were 0.48%, 0.35%, 0.48% and 0.19%, respectively. The recovery average (RA) was 100.22%. For UVDS, Beer's law was obeyed in the range 5.0-15.0 [mu]g/mL. The CC, AP and RP were respectively 0.9999, 0.05 and 0.47%. The CV for C, T, OD, S and SS were 0.64%, 0.84%, 0.62%, 0.54% and 0.15%, respectively. The RA was 99.02%. In HPLC determination, a LiChrospher[reg sign] 100 RP-18 (5 [mu]m) in LiChroCART[reg sign] 125-4 column at ambient temperature with a mobile phase consisting of methanol: (buffer solution citric acid-dibasic sodium phosphate pH 3.0) (55:45) and UV detection at 254 nm enabled the determination of piroxicam in C and T. The response peak area versus concentration presented linearity in the range 10.0-100.0 [mu]g/mL. The CC, AP and RP were 0.9997, 0.45 and 0.90%, respectively. The CV was 0.51%-0.82% and the RA, 97.13%. 14 refs., 1 fig., 5 tabs.

  17. PREPARATIVE ISOLATION AND PURIFICATION OF THREE GLYCINE-CONJUGATED CHOLIC ACIDS FROM PULVIS FELLIS SUIS BY HIGH-SPEED COUNTERCURRENT CHROMATOGRAPHY COUPLED WITH ELSD DETECTION

    OpenAIRE

    He, Jiao; Li, Jing; Sun, Wenji; Zhang, Tianyou; Ito, Yoichiro

    2012-01-01

    Coupled with evaporative light scattering detection, a high-speed counter-current chromatography (HSCCC) method was developed for preparative isolation and purification of three glycine-conjugated cholic acids, glycochenodeoxycholic acid (GCDCA), glycohyodeoxycholic acid (GHDCA) and glycohyocholic acid (GHCA) from Pulvis Fellis Suis (Pig gallbladder bile) for the first time. The separation was performed with a two-phase solvent system consisted of chloroform-methanol-water-acetic acid (65:30:...

  18. Analysis of the Constituents in “Zhu She Yong Xue Shuan Tong” by Ultra High Performance Liquid Chromatography with Quadrupole Time-of-Flight Mass Spectrometry Combined with Preparative High Performance Liquid Chromatography

    Directory of Open Access Journals (Sweden)

    Lin-Lin Wang

    2015-11-01

    Full Text Available “Zhu She Yong Xue Shuan Tong” lyophilized powder (ZSYXST, consists of a series of saponins extracted from Panax notoginseng, which has been widely used in China for the treatment of strokes. In this study, an ultra-high performance liquid chromatography with quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF/MS combined with preparative high performance liquid chromatography (PHPLC method was developed to rapidly identify both major and minor saponins in ZSYXST. Some high content components were removed through PHPLC in order to increase the sensitivity of the trace saponins. Then, specific characteristic fragment ions in both positive and negative mode were utilized to determine the types of aglycone, saccharide, as well as the saccharide chain linkages. As a result, 94 saponins, including 20 pairs of isomers and ten new compounds, which could represent higher than 98% components in ZSYXST, were identified or tentatively identified in commercial ZSYXST samples.

  19. On-line and precise measurement of iron wear using thin layer activation reactions by proton beam

    International Nuclear Information System (INIS)

    Kosako, Toshiso; Nishimura, Kazuo.

    1990-01-01

    For the purpose of the on-line measurement of iron wear, thin layer activation (TLA) method or surface layer activation (SLA) method has been carried out since early 1970s. This method uses the irradiation of charged particle beam like protons from an accelerator onto a metal surface to produce a thin activated layer of several tens μm. The wear of this activated layer is measured by nondestructive on-line method with a radiation detector. There are two methods of the measurement. One is the activity loss measurement on the surface, and the other is the activity measurement of the metal debris collected in a filter. The former method is considered here. The purpose it to measure the wear of engine cam noses to help the development of good engine oil. Proton beam irradiation with a tandem van de Graaff accelerator, wear calibration using a gamma ray spectrometer, on-line wear measurement of cam noses of car engines by TLA method and so on are reported. The 7.00 MeV proton beam from a van de Graaff accelerator was used for activation, and Co-56, Co-57 and Co-58 were obtained in thin layers. (K.I.)

  20. High-Performance Thin-Layer Chromatographic Quantification of Rosmarinic Acid and Rutin in Abnormal Savda Munziq

    Directory of Open Access Journals (Sweden)

    S. G. Tian

    2013-01-01

    Full Text Available A high-performance thin-layer chromatographic (HPTLC method has been established for simultaneous analysis of rosmarinic acid and rutin in Abnormal Savda Munziq (ASMq. A methanol extract of ASMq was used for quantification. The compounds were separated on silica gel H thin layer plate with ethyl acetate-formic acid-acetic acid-water 15 : 1 : 1 : 1.5 (v/v as a developer, trichloroethanol as the color reagent. The plates were scanned at 365 nm. The linear calibration data of rosmarinic acid and rutin were in the range of 0.0508 to 0.2540 μg (r=0.9964, 0.2707 to 1.35354 μg (r=0.9981, respectively. The recovery rate of rosmarinic acid was 99.17% (RSD = 2.92% and rutin was 95.24% (RSD = 2.38%. The method enables rapid screening, precise, selective, and sensitive quantification for pharmaceutical analysis.

  1. Short term changes in hydroperiod after thin layer sediment placement on a New Jersey salt marsh and implications for design

    Science.gov (United States)

    Piercy, C.; Carrillo, C. C.; VanZomeren, C. M.; Berkowitz, J.; Chasten, M. A.; Golden, D.; Jahn, J.; Welp, T. L.; Yepsen, M.

    2017-12-01

    Over the winter of 2015-2016, the U.S. Army Corps of Engineers Philadelphia District partnered with New Jersey Department of Environmental Protection, The Nature Conservancy, Green Trust Alliance, Green Vest, and Princeton Hydro to implement a wetland thin layer placement on a salt marsh to the west of Avalon, New Jersey using dredged sediments removed from the Federal navigation channel in response to impacts from Hurricane Sandy. Prior to sediment placement, the marsh exhibited signs of degradation, including fragmentation of the marsh plain. The marsh is characterized by large, open water areas ( 1 m deep) fringed with overhanging banks and punctuated by small remnant ( 1-5 m) islands of intact marsh. The objective of the placement effort was to increase the elevation of degraded marsh areas to a level commensurate with the growth of low marsh vegetation dominated by Spartina alterniflora Loisel and to provide a small ( 5-15 cm) elevation boost to vegetated marsh areas surrounding the open water pools. We examine changes in inundation and tidal exchange resulting from the thin layer placement immediately after placement and a year later. Changes in sediment grain size and other factors are also considered. Coupling hydrologic measurements with observed vegetation recovery, we identify target elevations and sediment depths relative to mean sea level and mean high water consistent with rapid recovery in initially vegetated and open water areas.

  2. Separation and preparation of xanthochymol and guttiferone E by high performance liquid chromatography and high speed counter-current chromatography combined with silver nitrate coordination reaction.

    Science.gov (United States)

    Li, Jun; Gao, Ruixi; Zhao, Dan; Huang, Xianju; Chen, Yu; Gan, Fei; Liu, Hui; Yang, Guangzhong

    2017-08-18

    Xanthochymol (XCM) and guttiferone E (GFE), a pair of π bond benzophenone isomers from Garcinia xanthochymus, were once reported to be difficult or impossible to separate. The present study reports the successful separation of these two isomers through high performance liquid chromatography (HPLC), as well as their effective isolation using high speed counter-current chromatography (HSCCC) based on the silver nitrate (AgNO 3 ) coordination reaction. First, an effective HPLC separation system was developed, achieving a successful baseline separation with resolution of 2.0. Based on the partition coefficient (K) resolved by HPLC, the two-phase solvent system was determined as n-hexane, methanol and water with the uncommon volume ratio of 4:6:1. A crude extract of Garcinia xanthochymus (0.2g) was purified by normal HSCCC and refined with AgNO 3 -HSCCC. Monomers of XCM and GFE were identified by HPLC, mass spectrometry (MS) and nuclear magnetic resonance (NMR). The results demonstrate the separation and isolation of π bond benzophenone isomers using ordinary octadecyl silane (C 18 ) columns and HSCCC. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Preparation of labelled antituberculotics for clarifying specific problems in therapy optimization. 2. Preparation of tritiated rifampicin and an orally administrable pharmaceutical, investigation of the stability of labelling

    Energy Technology Data Exchange (ETDEWEB)

    Winsel, K.; Iwainsky, H. (Forschungsinstitut fuer Lungenkrankheiten und Tuberkulose, Berlin-Buch (German Democratic Republic)); Mittag, E.; Kiessling, M. (Zentralinstitut fuer Kernforschung, Rossendorf bei Dresden (German Democratic Republic)); Koehler, H. (Zentralklinik fuer Herz- und Lungenkrankheiten, Bad Berka (German Democratic Republic))

    1985-09-01

    Labelling of RMP according to the Wilzbach method results in a fragmentation of the molecule. The synthesis of (/sup 3/H)-RMP is possible by the reaction of 1-amino-4-(/sup 3/H)-methylpiperazine with 3-formylrifamycin SV. It consists of the following steps: 1 nitrosopiperazine, 1-aminopiperazine, 1-benzalaminopiperazine, 1-benzalamino-4-(/sup 3/H)-methylpiperazine, 1-amino-4-(/sup 3/H)methylpiperazinedihydrochloride. The base was liberated from the hydrochloride directly in the reaction mixture in the presence of 3-formylrifamycin SV. Excluding oxygen and light the reaction is nearly quantitative. The product was purified by preparative thin-layer chromatography. After oral administration measurements of the (/sup 3/H) activity reflect with good approximation the antimycobacterial activity, although to a small degree the labelled group is eliminated by metabolic processes.

  4. Separation of four flavonol glycosides from Solanum rostratum Dunal using aqueous two-phase flotation followed by preparative high-performance liquid chromatography.

    Science.gov (United States)

    Chang, Lin; Shao, Qian; Xi, Xingjun; Chu, Qiao; Wei, Yun

    2017-02-01

    Aqueous two-phase flotation followed by preparative high-performance liquid chromatography was used to separate four flavonol glycosides from Solanum rostratum Dunal. In the aqueous two-phase flotation section, the effects of sublation solvent, solution pH, (NH 4 ) 2 SO 4 concentration in aqueous solution, cosolvent, N 2 flow rate, flotation time, and volumes of the polyethylene glycol phase on the recovery were investigated in detail, and the optimal conditions were selected: 50 wt% polyethylene glycol 1000 ethanol solvent as the flotation solvent, pH 4, 350 g/L of (NH 4 ) 2 SO 4 concentration in aqueous phase, 40 mL/min of N 2 flow rate, 30 min of flotation time, 10.0 mL of flotation solvent volume, and two times. After aqueous two-phase flotation concentration, the flotation products were purified by preparative high-performance liquid chromatography. The purities of the final products A and B were 98.1 and 99.0%. Product B was the mixture of three compounds based on the analysis of high-performance liquid chromatography at the temperature of 10°C, while product A was hyperoside after the identification by nuclear magnetic resonance. Astragalin, 3'-O-methylquercetin 3-O-β-d-galactopyranoside, and 3'-O-methylquercetin 3-O-β-d-glucopyranoside were obtained with the purity of 93.8, 97.1, and 99.2%, respectively, after the further separation of product B using preparative high-performance liquid chromatography. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Electrochemical synthesis, structure and phase composition of nano structured amorphous thin layers of NiW and Ni-Mo

    International Nuclear Information System (INIS)

    Vitina, I.; Lubane, M.; Belmane, V.; Rubene, V.; Krumina, A.

    2006-01-01

    Full text: Nano structured Ni-W thin layers containing W 6-37 wt.% were electrodeposited on a copper substratum. The W content in the layer changes, and it is determined by the electrolyte pH in the range 8.0-9.6 and the cathode current density in the range 1.0-10.0 A/dm 2 . The atomic composition and thermal stability of structure of the electrodeposited thin layers depend for the most part on the conditions of the electrodeposition and less on the W content in the layer. Cracking of the Ni-W layers electrodeposited at the electrolyte pH 8.5 and containing 34-37 wt.% W and 8.5 wt.% W was observed. The cracking increases at heating at 400 deg C for 50 h. On the contrary, no cracking of the Ni-W layer electrodeposited at the electrolyte pH 9.0 and containing 25 wt.% W was observed. The atomic composition of the layer remains practically unchanged at heating at 400 deg C for 50 h. The layer binds oxygen up to 7 wt.%. According to X-ray diffraction, in spite of the W content 35-37 wt.% in the layer, nano structured layers rather than amorphous layers were obtained which at heating at 400 deg C depending on the W content crystallises as Ni or intermetallic compounds Ni x W y if the W content is approx. 25 wt.%. Amorphous Ni-Mo alloys containing 35-52 wt.% Mo was electrodeposited on copper substratum at the cathode current densities of 0.5-1.5 A/dm2 and the electrolyte pH 6.8-8.6. Formation of thin layer (∼1-2μm) of X-ray amorphous Ni-Mo alloy, the Mo content, the characteristics of structure depend on the electrodeposition process, the electrolyte pH, and the cathode current density. The Ni-Mo layer deposited at the electrolyte pH above 8.6 and below average 6.8 had a nanocrystalline structure rather than characteristics of amorphous structure. Ni- W and Ni-Mo alloys were electrodeposited from citrate electrolyte not containing ammonium ions

  6. Pore pressure propagation in a permeable thin-layer coal seam based on a dual porosity model: A case of risk prediction of water inrush in coalmines

    Science.gov (United States)

    Zhu, B.; Gao, F.; Yang, J. W.; Zhou, G. Q.

    2016-08-01

    Thin-layer coal seams, a type of filling coal rock body, are considered aquifer systems made up of dual porosity medium with immediate floor. A numerical simulation for the pore pressure propagation along a thin-layer coal seam was carried out for the case of the Zhaogezhuang coalmine in China. By valuing the permeability (Kf ) of the thin-layer coal seam, pore pressure variation with time was simulated and compared to the analytical solutions of a dual porosity model (DPM). The main conclusions were drawn as follow: (1) Seepage in the thin-layer coal seam was predominant in the whole process, and the distance of seepage was lengthened and the pore pressure decreased with increased Kf , (2) A series of simulated hydraulic graphs demonstrated that the pore pressure characteristics of peak-occurring and time-lag effects agreed with the analytical solutions of DPM; (3) By adjusting the parameters of DPM, two results of analytical solutions and numerical solutions fit well, particularly in the thin-layer coal seam, (4) The power law relationship between the peak-values and lag time of pore pressure were derived statistically under consideration of the Kf parameter in the range of 10-8 to 10-10 m2/pa-s orders, and it was reasonable that the Kf of the thin-layer coal seam was in the range of 10-8 m2/pa-s orders. The results were significantly helpful in decision-making for mining water prevention and prediction in practice.

  7. Enhancement of grain size and crystallinity of thin layers of pentacene grown under magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Tabata, Kenichi [Division of Materials Science, Faculty of pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573 (Japan); Yamamoto, Yohei, E-mail: yamamoto@ims.tsukuba.ac.jp [Division of Materials Science, Faculty of pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573 (Japan); Tsukuba Research Center for Interdisciplinary Materials Science (TIMS), Faculty of pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573 (Japan); Center for Integrated Research in Fundamental Science and Technology (CiRfSE), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8571 (Japan)

    2016-03-31

    Field-effect mobilities (μ) of pentacene films, prepared by a thermal deposition under a magnetic field (H-field), were largely enhanced, in comparison with that prepared without an H-field. Under a perpendicular H-field with respect to the substrate surface, the crystallinity of the edge-on pentacene orientation is enhanced, resulting in the 9-fold enhancement of μ. Furthermore, under parallel H-field with respect to the substrate surface, μ of the pentacene films were 23-fold greater than that prepared without the H-field. The surface morphology studies by atomic force microscopy of the ultra thin films of pentacene clarified that the grain size of the pentacene at the interface with the substrate is larger for films under parallel H-field than that prepared without an H-field. The simple and effective method for enhancing the semiconducting properties of the organic thin films gives high technological impact in its application to organic electronics. - Highlights: • Magnetic-field effect on the crystallinity of pentacene thin films • Magnetic-field effect on the morphology of pentacene thin films • Enhanced field-effect charge carrier mobility of pentacene thin films.

  8. Enhancement of grain size and crystallinity of thin layers of pentacene grown under magnetic field

    International Nuclear Information System (INIS)

    Tabata, Kenichi; Yamamoto, Yohei

    2016-01-01

    Field-effect mobilities (μ) of pentacene films, prepared by a thermal deposition under a magnetic field (H-field), were largely enhanced, in comparison with that prepared without an H-field. Under a perpendicular H-field with respect to the substrate surface, the crystallinity of the edge-on pentacene orientation is enhanced, resulting in the 9-fold enhancement of μ. Furthermore, under parallel H-field with respect to the substrate surface, μ of the pentacene films were 23-fold greater than that prepared without the H-field. The surface morphology studies by atomic force microscopy of the ultra thin films of pentacene clarified that the grain size of the pentacene at the interface with the substrate is larger for films under parallel H-field than that prepared without an H-field. The simple and effective method for enhancing the semiconducting properties of the organic thin films gives high technological impact in its application to organic electronics. - Highlights: • Magnetic-field effect on the crystallinity of pentacene thin films • Magnetic-field effect on the morphology of pentacene thin films • Enhanced field-effect charge carrier mobility of pentacene thin films

  9. Identification of bound alcohols in soil humic acids by gas chromatography-mass spectrometry

    OpenAIRE

    Berthier , Gersende; Dou , Sen; Peakman , Torren; Lichtfouse , Eric

    2000-01-01

    International audience; Humic acids are complex, partly macromolecular, yellow-brownish substances occurring in soils, waters and sediments. In order to shed some light on their molecular structure, crop humic acids were cleaved by alkaline hydrolysis (KOH). The products were fractionated by thin layer chromatography to give mono-alcohols which were analysed as acetate derivatives by gas chromatography coupled to mass spectrometry. Linear alcohols, sterols, stanols and plant-derived triterpen...

  10. Preparation of labelled antituberculotics for clarifying specific problems in therapy optimization. 2

    International Nuclear Information System (INIS)

    Winsel, K.; Iwainsky, H.; Mittag, E.; Kiessling, M.; Koehler, H.

    1985-01-01

    Labelling of RMP according to the Wilzbach method results in a fragmentation of the molecule. The synthesis of [ 3 H]-RMP is possible by the reaction of 1-amino-4-[ 3 H]-methylpiperazine with 3-formylrifamycin SV. It consists of the following steps: 1 nitrosopiperazine, 1-aminopiperazine, 1-benzalaminopiperazine, 1-benzalamino-4-[ 3 H]-methylpiperazine, 1-amino-4-[ 3 H]methylpiperazinedihydrochloride. The base was liberated from the hydrochloride directly in the reaction mixture in the presence of 3-formylrifamycin SV. Excluding oxygen and light the reaction is nearly quantitative. The product was purified by preparative thin-layer chromatography. After oral administration measurements of the [ 3 H] activity reflect with good approximation the antimycobacterial activity, although to a small degree the labelled group is eliminated by metabolic processes. (author)

  11. SPE/TLC/Densitometric Quantification of Selected Synthetic Food Dyes in Liquid Foodstuffs and Pharmaceutical Preparations

    Directory of Open Access Journals (Sweden)

    Anna W. Sobańska

    2017-01-01

    Full Text Available Selected synthetic food dyes (tartrazine, Ponceau 4R, Brilliant Blue, orange yellow, and azorubine were isolated from liquid preparations (mouthwashes and beverages by Solid Phase Extraction on aminopropyl-bonded silica with diluted aqueous sodium hydroxide as an eluent. The extraction step was followed by thin layer chromatography on silica gel 60 with chloroform-isopropanol-25% aq. ammonia 1 : 3 : 1 (v/v/v as mobile phase and the densitometric quantification of dyes was achieved using quadratic calibration plots (R2>0.997; LOQ = 0.04–0.09 μgspot−1. The overall recoveries for all studied dyes were at the average level of over 90% and the repeatability of the proposed procedure (CV ≤ 4.1% was sufficient to recommend it for the routine quantification of the aforementioned dyes in liquid matrices.

  12. HIGH PERFORMANCE THIN LAYER CHROMATOGRAPHIC DETERMINATION OF CAFFEIC ACID AND ROSMARINIC ACID FROM THE LEAVES OF Orthosiphon stamineus

    Directory of Open Access Journals (Sweden)

    M. Amzad Hossain

    2010-06-01

    Full Text Available This paper presents the studies performed on extraction of Orthosiphon stamineus, Benth by using different solvent for the identification and quantification of the caffeic acid derivatives such as caffeic acid  and rosmarinic acid which confers to the leaves of this plant with remarkable pharmaceutical properties. High performance thin-layer chromatographic (HPTLC allows the identification and the quantification of more than 20 samples in the same chromatographic run. The analysis of the samples requires 15-30 min compared with more than 2 h using a typical HPLC method. Using the techniques of the HPTLC and the UV-VIS spectra we have found that the extraction of this herb plant contain, the caffeic acid and rosmarinic acid ranging between 0.029% up to 0.506% and up to 0.24% to 2.24% respectively.     Keywords: Caffice acid derivatives, quantification, Malaysian Orthosiphon stamineus, HPTLC

  13. Specific interface area in a thin layer system of two immiscible liquids with vapour generation at the contact interface

    Science.gov (United States)

    Pimenova, Anastasiya V.; Gazdaliev, Ilias M.; Goldobin, Denis S.

    2017-06-01

    For well-stirred multiphase fluid systems the mean interface area per unit volume, or “specific interface area” SV, is a significant characteristic of the system state. In particular, it is important for the dynamics of systems of immiscible liquids experiencing interfacial boiling. We estimate the value of parameter SV as a function of the heat influx {\\dot{Q}}V to the system or the average system overheat above the interfacial boiling point. The derived results can be reformulated for the case of an endothermic chemical reaction between two liquid reagents with the gaseous form of one of the reaction products. The final results are restricted to the case of thin layers, where the potential gravitational energy of bubbles leaving the contact interface is small compared to their surface tension energy.

  14. Rapid thin-layer chromatographic photodensitometric method for the determination of metoclopramide and clebopride in the presence of some of their metabolic products.

    Science.gov (United States)

    Huizing, G; Beckett, A H; Segura, J

    1979-04-21

    Metoclopramide and its newly developed analogue clebopride, together with some of their metabolic products are quantitated, following extraction from biological tissues and fluids, and subsequent separation on silica gel thin-layer chromatographic plates. Diazotisation, followed by coupling with N-(1-naphthyl)ethylenediammonium dichloride, carried out on the thin-layer plate, is utilised for visualisation. The intensity of the spots is measured by photodensitometric analysis. The effect of variation of various experimental conditions is studied. The method has proven to be satisfactory for the measurement of 20 ng/ml of these compounds in biological material; the results are well within the accepted limits of deviation.

  15. Experimental study of water desorption isotherms and thin-layer convective drying kinetics of bay laurel leaves

    Science.gov (United States)

    Ghnimi, Thouraya; Hassini, Lamine; Bagane, Mohamed

    2016-12-01

    The aim of this work is to determine the desorption isotherms and the drying kinetics of bay laurel leaves ( Laurus Nobilis L.). The desorption isotherms were performed at three temperature levels: 50, 60 and 70 °C and at water activity ranging from 0.057 to 0.88 using the statistic gravimetric method. Five sorption models were used to fit desorption experimental isotherm data. It was found that Kuhn model offers the best fitting of experimental moisture isotherms in the mentioned investigated ranges of temperature and water activity. The Net isosteric heat of water desorption was evaluated using The Clausius-Clapeyron equation and was then best correlated to equilibrium moisture content by the empirical Tsami's equation. Thin layer convective drying curves of bay laurel leaves were obtained for temperatures of 45, 50, 60 and 70 °C, relative humidity of 5, 15, 30 and 45 % and air velocities of 1, 1.5 and 2 m/s. A non linear regression procedure of Levenberg-Marquardt was used to fit drying curves with five semi empirical mathematical models available in the literature, The R2 and χ2 were used to evaluate the goodness of fit of models to data. Based on the experimental drying curves the drying characteristic curve (DCC) has been established and fitted with a third degree polynomial function. It was found that the Midilli Kucuk model was the best semi-empirical model describing thin layer drying kinetics of bay laurel leaves. The bay laurel leaves effective moisture diffusivity and activation energy were also identified.

  16. Thin-layer agar (TL7H11 for rapid isolation of Mycobacterium tuberculosis in sputum specimens

    Directory of Open Access Journals (Sweden)

    Habiba Binte Alam

    2016-08-01

    Full Text Available Background: Tuberculosis (TB remains one of the major causes of death from a single infectious agent worldwide. The early detection of new cases of pulmonary tuberculosis is an important goal in tuberculosis control program.Objective: 1n this study, thin layer agar (TLA culture was compared with Lowenstein-Jensen (LJ culture for rapid detection of pulmonary tuberculosis. Methods: It was a cross sectional study conducted in National Tuberculosis Reference Labora­tory (NTRL of National Institute of Disease of Chest and Hospital (NIDCH, Dhaka, from July 2010 to June 2011. A total of 100 sputum smear positive for acid fast bacilli (AFB by Z-N staining, pulmonary tuberculosis patients were included in this study. Samples were processed by modified Petroff method and then cultured on thin layer 7H11(TL7H11 plates and L-J tubes. TL7H11 plates were observed microscopically for rnicrocolony growth once a week for 6 weeks, and L-J tubes were observed once a week for 8 weeks. Results: The recovery rates of mycobacteria on only TLA, only LJ and on both media were 90%, 97% and 88% respectively. Overall positivity was 99% in both L-J and TLA media. Mean time for detection of mycobacteria on TLA was 9.04±1.66 days compared to 21.78±6.19 days on L-J media. The rate of contamination was higher (6% in L-J media than in TLA media (4%. Conclusion: The TL7H11 media can be used as an alternative to the Lowenstein-Jensen medium for early isolation of mycobacteria in resource constrained settings.

  17. Separation and analysis of phenolic acids from Salvia miltiorrhiza and its related preparations by off-line two-dimensional hydrophilic interaction chromatography×reversed-phase liquid chromatography coupled with ion trap time-of-flight mass spectrometry.

    Science.gov (United States)

    Sun, Wanyang; Tong, Ling; Miao, Jingzhuo; Huang, Jingyi; Li, Dongxiang; Li, Yunfei; Xiao, Hongting; Sun, Henry; Bi, Kaishun

    2016-01-29

    Salvia miltiorrhiza (SM) is one of the most widely used Traditional Chinese Medicine. Active constituents of SM mainly contain hydrophilic phenolic acids (PAs) and lipophilic tanshinones. However, due to the existing of multiple ester bonds and unsaturated bonds in the structures, PAs have numerous chemical conversion products. Many of them are so low-abundant that hard to be separated using conventional methods. In this study, an off-line two-dimensional liquid chromatography (2D-LC) method was developed to separate PAs in SM and its related preparations. In the first dimension, samples were fractionated by hydrophilic interaction chromatography (HILIC) (Acchrom×Amide, 4.6×250mm, 5μm) mainly based on the hydrogen bonding effects. The fractions were then separated on reversed-phase liquid chromatography (RP-LC) (Acquity HSS T3, 2.1×50mm, 1.7μm) according to hydrophobicity. For the selective identification of PAs, diode array detector (DAD) and electrospray ionization tandem ion trap time-of-flight mass spectrometry (ESI-IT-TOF-MS) were employed. Practical and effective peak capacities of all the samples were greater than 2046 and 1130, respectively, with the orthogonalities ranged from 69.7% to 92.8%, which indicated the high efficiency and versatility of this method. By utilizing the data post-processing techniques, including mass defect filter, neutral loss filter and product ion filter, a total of 265 compounds comprising 196 potentially new PAs were tentatively characterized. Twelve kinds of derivatives, mainly including glycosylated compounds, O-alkylated compounds, condensed compounds and hydrolyzed compounds, constituted the novelty of the newly identified PAs. The HILIC×RP-LC/TOF-MS system expanded our understanding on PAs of S. miltiorrhiza and its related preparations, which could also benefit the separation and characterization of polar constituents in complicated herbal extracts. Copyright © 2016. Published by Elsevier B.V.

  18. Investigation of vanadium and nitride alloys thin layers deposited by PVD

    Directory of Open Access Journals (Sweden)

    Nouveau C.

    2012-06-01

    Full Text Available In this work we present the technique of magnetron vapor deposition and the effect of several deposition parameters on the structural and morphological properties of prepared thin films. It was noted that the deposition time has an effect on the crystallinity, mechanical properties such as residual stress, roughness surface and the layer composition from target products. Studies were carried out on layers of vanadium (V and the nitride vanadium (VN.

  19. Preparation of Erbium-169 (169Er) Using Natural Erbium Target

    International Nuclear Information System (INIS)

    Azmairit Aziz; Nana Suherman

    2009-01-01

    The therapeutic radiopharmaceuticals which is labelled by β-particle emission are now increasingly used in nuclear medicine. Erbium-169 ('1 69 Er) is one of radioisotopes that can be used for radiation synovectomy (radio synovectomy) in the treatment of inflammatory joint diseases (arthritis) due to its β- particle emission (T 1/2 =9.4 days, E β maximum =0.34 MeV). The preliminary study on preparation of 169 Er by using natural erbium oxide (Er 2 O 3 ) target irradiated at TRIGA 2000 Bandung reactor has been carried out. The irradiated target was dissolved in hydrochloric acid solution and gentle warming. The optimum condition of 169 Er preparation was obtained by dissolution of 169 Er 2 O 3 by using 1N HCl solution. The radiochemical purity of 169 ErCl 3 was determined by paper chromatography, thin layer chromatography and paper electrophoresis techniques. The solution of 169 ErCl 3 formed was obtained with the pH of 1.5 – 2, clear, with the specific activity of 0.48 – 0.71 MBq/mg Er. The solution has the radiochemical purity of 98.32 ± 1.28% and the radionuclide purity of 99.98%. Study on the stability of 169 ErCl 3 solution showed that the solution was still stable for 4 days at room temperature with the radiochemical purity more than 95%. (author)

  20. Development of method of tritium labeling of pharmacological preparate of drotaverine hydrochloride (NOSPA)

    International Nuclear Information System (INIS)

    Kim, A.A.; Djuraeva, G.T.; Shukurov, B.V.

    2004-01-01

    Full text: The method for tritium labeling of pharmacological preparate of drotaverine hydrochloride (no spa) was developed. Drotaverine hydrochloride was labeled by thermally activated tritium in apparatus for tritium labeling. The optimum regime of labeling was selected. The system of purification of tritium labeled drotaverine hydrochloride by thin layer chromatography (TLC) has been developed. The TLC system of purification of tritium labeled drotaverine hydrochloride was developed. Tritium labeled preparation of drotaverine hydrochloride was purified by TLC on silicagel in system isopropanol: ammonia: water (8:1:1). We found appearance of additional fractions in tritium labeled preparation of drotaverine hydrochloride that testifies to partial transformation of drotaverine hydrochloride during procedure of labeling. Application of TLC for purification of tritium labeled preparation allows to purify completely drotaverine hydrochloride of by-products. The output of purified tritium labeled preparation of drotaverine hydrochloride was about 25 %. The received preparation had specific radioactivity - 3,2 MBq/mg, radiochemical purity of a preparation was 95 %. TLC purification seems inexpensive, fast and suitable for purification of tritium-labeled drotaverine hydrochloride. Thus developed method allows obtain tritium labeled preparation of drotaverine hydrochloride (no - spa), suitable for medical and biologic researches