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Sample records for diphenylcarbazides

  1. Chromium(VI) release from leather and metals can be detected with a diphenylcarbazide spot test

    DEFF Research Database (Denmark)

    Bregnbak, David; Johansen, Jeanne D.; Jellesen, Morten Stendahl

    2015-01-01

    Along with chromium, nickel and cobalt are the clinically most important metal allergens. However, unlike for nickel and cobalt, there is no validated colorimetric spot test that detects chromium. Such a test could help both clinicians and their patients with chromium dermatitis to identify culprit...... exposures. To evaluate the use of diphenylcarbazide (DPC) as a spot test reagent for the identification of chromium(VI) release. A colorimetric chromium(VI) spot test based on DPC was prepared and used on different items from small market surveys. The DPC spot test was able to identify chromium(VI) release...

  2. Chromium(VI) release from leather and metals can be detected with a diphenylcarbazide spot test.

    Science.gov (United States)

    Bregnbak, David; Johansen, Jeanne D; Jellesen, Morten S; Zachariae, Claus; Thyssen, Jacob P

    2015-11-01

    Along with chromium, nickel and cobalt are the clinically most important metal allergens. However, unlike for nickel and cobalt, there is no validated colorimetric spot test that detects chromium. Such a test could help both clinicians and their patients with chromium dermatitis to identify culprit exposures. To evaluate the use of diphenylcarbazide (DPC) as a spot test reagent for the identification of chromium(VI) release. A colorimetric chromium(VI) spot test based on DPC was prepared and used on different items from small market surveys. The DPC spot test was able to identify chromium(VI) release at 0.5 ppm without interference from other pure metals, alloys, or leather. A market survey using the test showed no chromium(VI) release from work tools (0/100). However, chromium(VI) release from metal screws (7/60), one earring (1/50), leather shoes (4/100) and leather gloves (6/11) was observed. We found no false-positive test reactions. Confirmatory testing was performed with X-ray fluorescence (XRF) and spectrophotometrically on extraction fluids. The use of DPC as a colorimetric spot test reagent appears to be a good and valid test method for detecting the release of chromium(VI) ions from leather and metal articles. The spot test has the potential to become a valuable screening tool. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  3. Assessment of chromium(VI) release from 848 jewellery items by use of a diphenylcarbazide spot test

    DEFF Research Database (Denmark)

    Bregnbak, David; Johansen, Jeanne D.; Hamann, Dathan

    2016-01-01

    We recently evaluated and validated a diphenylcarbazide(DPC)-based screening spot test that can detect the release of chromium(VI) ions (≥0.5 ppm) from various metallic items and leather goods (1). We then screened a selection of metal screws, leather shoes, and gloves, as well as 50 earrings......, and identified chromium(VI) release from one earring. In the present study, we used the DPC spot test to assess chromium(VI) release in a much larger sample of jewellery items (n=848), 160 (19%) of which had previously be shown to contain chromium when analysed with X-ray fluorescence spectroscopy (2)....

  4. False-positive result when a diphenylcarbazide spot test is used on trivalent chromium-passivated zinc surfaces

    DEFF Research Database (Denmark)

    Reveko, Valeriia; Lampert, Felix; Din, Rameez Ud

    2018-01-01

    chromium passivation on zinc; however, subsequent analysis by XPS could not confirm the presence of chromium in a hexavalent state. Conclusions Unintended oxidation of DPC induced by atmospheric corrosion is suggested as a possible reason for the false-positive reaction of the DPC test on a trivalent......A colorimetric 1,5-diphenylcarbazide (DPC)-based spot test can be used to identify hexavalent chromium on various metallic and leather surfaces. DPC testing on trivalent chromium-passivated zinc surfaces has unexpectedly given positive results in some cases, apparently indicating the presence...... of hexavalent chromium; however, the presence of hexavalent chromium has never been confirmed with more sensitive and accurate test methods. Objectives To examine the presence of hexavalent chromium on trivalent chromium-passivated zinc surfaces with a DPC-based spot test. Methods A colorimetric DPC spot test...

  5. [Investigation of concentration levels of chromium(VI) in bottled mineral and spring waters by high performance ion chromatography technique with application of postcolumn reaction with 1,5-diphenylcarbazide and VIS detection].

    Science.gov (United States)

    Swiecicka, Dorota; Garboś, Sławomir

    2008-01-01

    The aim of this work was optimization and validation of the method of determination of Cr(VI) existing in the form of chromate(VI) in mineral and spring waters by High Performance Ion Chromatography (HPIC) technique with application of postcolumn reaction with 1,5-diphenylcarbazide and VIS detection. Optimization of the method performed with the use of initial apparatus parameters and chromatographic conditions from the Method 218.6 allowed to lowering detection limit for Cr(VI) from 400 ng/l to 2 ng/l. Thanks to very low detection limit achieved it was possible to determine of Cr(VI) concentrations in 25 mineral and spring waters presented at Polish market. In the cases of four mineral and spring waters analyzed, determined Cr(VI) concentrations were below of quantification limit (waters the concentrations of chromium(VI) were determined in the range of 5.6 - 1281 ng/l. The fact of existence of different Cr(VI) concentrations in investigated waters could be connected with secondary contamination of mineral and spring waters by chromium coming from metal installations and fittings. One should be underlined that even the highest determined concentration level of chromium(VI) was below of the maximum admissible concentration of total chromium presented in Polish Decree of Minister of Health from April 29th 2004. Therefore after taking into account determined in this work concentration of Cr(VI), the consumption of all waters analyzed in this study does not lead to essential human health risk.

  6. Magnesium analysis. Spectrophotometric determination of chromium

    International Nuclear Information System (INIS)

    Anon.

    Chromium determination in magnesium used in uranium fabrication by magnesiothermics, applicable for chromium content between 2 to 10 ppm. Magnesium is dissolved in sulfuric acid, oxidized by potassium permanganate, the excess of permanganate is eliminated by sodium nitride. Spectrophotometry at 540 nm of the chromium (VI)-diphenylcarbazide complex [fr

  7. On-line Speciation of Cr(III) and Cr(VI) by Flow Injection Analysis With Spectrophotometric Detection and Chemometrics

    DEFF Research Database (Denmark)

    Diacu, Elena; Andersen, Jens Enevold Thaulov

    2003-01-01

    A flow injection system has been developed, for on-line speciation. of Cr(III) and Cr(VI) by the Diphenylcarbazide (DPC) method with H2O2 oxidation followed by spectrophotometric detection at the 550 nm wavelength. The data thus obtained were subjected to a chemometric analysis (PLS), which showe...

  8. Determination of tracer quantities of chromium in uranium

    International Nuclear Information System (INIS)

    Huart, A.

    1959-01-01

    A method is described for the photometric determination of chromium in uranium by absorbency at 540 mμ of the Cr(VI) diphenylcarbazide combination. After attack by nitric acid, the solution is made perchloric, and the chromium oxidised at the boiling point by permanganate. Excess oxidant is removed by hydrochloric acid. Study of operating conditions resulted in a method with an accuracy of ± 0,5 ppm for 0,5 to 15 ppm chromium in the metal. (author) [fr

  9. An Investigation on the Extraction and Quantitation of a Hexavalent Chromium in Acrylonitrile Butadiene Styrene Copolymer (ABS) and Printed Circuit Board (PCB) by Ion Chromatography Coupled with Inductively Coupled Plasma Atomic Emission Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Nam, Sang Ho; Kim, Yu Na [Mokpo National University, Muan (Korea, Republic of)

    2012-06-15

    A hexavalent chromium (Cr (VI)) is one of the hazardous substances regulated by the RoHS. The determination of Cr (VI) in various polymers and printed circuit board (PCB) has been very important. In this study, the three different analytical methods were investigated for the determination of a hexavalent chromium in Acrylonitrile Butadiene Styrene copolymer (ABS) and PCB. The results by three analytical methods were obtained and compared. An analytical method by UV-Visible spectrometer has been generally used for the determination of Cr (VI) in a sample, but a hexavalent chromium should complex with diphenylcarbazide for the detection in the method. The complexation did make an adverse effect on the quantitative analysis of Cr (VI) in ABS. The analytical method using diphenylcarbazide was also not applicable to printed circuit board (PCB) because PCB contained lots of irons. The irons interfered with the analysis of hexavalent chromium because those also could complex with diphenylcarbazide. In this study, hexavalent chromiums in PCB have been separated by ion chromatography (IC), then directly and selectively detected by inductively coupled plasma atomic emission spectrometry (ICP-AES). The quantity of Cr (VI) in PCB was 0.1 mg/kg

  10. Myrsinoic A acid and its derivative: in vitro inhibitors of photosynthesis; Acido myrsinoico A e derivado: inibidores da fotossintese in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Burger, Marcela Carmen de M.; Oliveira, Gracielle S. de; Menezes, Antonio Carlos S [Universidade Estadual de Goias, Anapolis, GO (Brazil). Unidade Universitaria de Ciencias Exatas e Tecnologicas; Vieira, Paulo Cezar; Silva, Maria Fatima das G.F. da [Universidade Federal de Sao Carlos (UFSCar), SP (Brazil). Dept. de Quimica; Veiga, Thiago A.M., E-mail: tveiga@unifesp.br [Universidade Federal de Sao Paulo (UNIFESP), SP (Brazil). Inst. de Ciencias Ambientais, Quimicas e Farmaceuticas. Dept. de Ciencias Exatas e da Terra

    2012-07-01

    Myrsinoic A acid, isolated from Myrsine cuneifolia and its hydrogenated derivative had their effect on photosynthesis tested. The compounds inhibited the electron flow (basal, phosphorylating and uncoupled) from water to methyl viologen; therefore, they act as Hill reaction inhibitors in spinach thylakoids. They inhibited partial reactions of PSII electron flow from water to 2,5-dichloro-1,4-benzoquinone, from water to sodium silicomolybdate, and partially electron flow from diphenylcarbazide to 2,6-dichloroindophenol. Their inhibition sites were at the donor and acceptor sides of PSII, between P{sub 680} and Q{sub A}. Chlorophyll {alpha} fluorescence measurements confirmed the behavior of the compounds (pool of quinones). (author)

  11. Myrsinoic A acid and its derivative: in vitro inhibitors of photosynthesis

    International Nuclear Information System (INIS)

    Burger, Marcela Carmen de M.; Oliveira, Gracielle S. de; Menezes, Antonio Carlos S.; Vieira, Paulo Cezar; Silva, Maria Fatima das G.F. da; Veiga, Thiago A.M.

    2012-01-01

    Myrsinoic A acid, isolated from Myrsine cuneifolia and its hydrogenated derivative had their effect on photosynthesis tested. The compounds inhibited the electron flow (basal, phosphorylating and uncoupled) from water to methyl viologen; therefore, they act as Hill reaction inhibitors in spinach thylakoids. They inhibited partial reactions of PSII electron flow from water to 2,5-dichloro-1,4-benzoquinone, from water to sodium silicomolybdate, and partially electron flow from diphenylcarbazide to 2,6-dichloroindophenol. Their inhibition sites were at the donor and acceptor sides of PSII, between P 680 and Q A . Chlorophyll α fluorescence measurements confirmed the behavior of the compounds (pool of quinones). (author)

  12. Determination of tracer quantities of chromium in uranium; Dosage de traces de chrome dans l'uranium

    Energy Technology Data Exchange (ETDEWEB)

    Huart, A [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1959-07-01

    A method is described for the photometric determination of chromium in uranium by absorbency at 540 m{mu} of the Cr(VI) diphenylcarbazide combination. After attack by nitric acid, the solution is made perchloric, and the chromium oxidised at the boiling point by permanganate. Excess oxidant is removed by hydrochloric acid. Study of operating conditions resulted in a method with an accuracy of {+-} 0,5 ppm for 0,5 to 15 ppm chromium in the metal. (author) [French] Le chrome est dose dans l'uranium par photometrie a 540 m{mu} du compose colore Cr(VI) diphenylcarbazide. Apres mise en solution critique et reprise perchlorique a chaud, le chrome est oxyde en milieu acide et a l'ebullition par le permanganate. L'exces d'oxydant est ensuite detruit par l'acide chlorhydrique a l'ebullition. L'etude des conditions experimentales aboutit a un mode operatoire strict. La precision obtenue pour des teneurs comprises entre 0,5 et 15 ppm dans le metal est de 0,5 ppm. (auteur)

  13. Evaluation of herbicidal potential of depsides from Cladosporium uredinicola, an endophytic fungus found in Guava fruit

    International Nuclear Information System (INIS)

    Medeiros, Livia S. de; Sampaio, Olivia M.; Silva, Maria Fatima das G.F. da; Rodrigues Filho, Edson; Veiga, Thiago Andre M.

    2012-01-01

    Two natural products produced by Cladosporium uredinicola, an endophytic fungus isolated from guava fruit, were evaluated for their effects on photosynthesis. Both of them inhibited electron flow (basal, phosphorylating, and uncoupled) from water to methylviologen (MV), acting as Hill reaction inhibitors in freshly lysed spinach thylakoids. These polyketides, belonging to depsides class, inhibited partial reactions of photosystem II (PS II) electron flow from water to 2,5-dichloro-1,4-benzoquinone (DCBQ), from water to sodium silicomolybdate (SiMo Na + ), and partially inhibited electron flow from 1,5-diphenylcarbazide (DPC) to 2,6-dichloroindophenol (DCPIP). These results established that the depsides sites of inhibition are located on the donor and acceptor sides of PS II, between P680 and QA . Chlorophyll a fluorescence measurements corroborated this mechanism of action. None of the tested compounds inhibited photosystem I (PS I) electron transport. (author)

  14. Especiação redox de cromo em solo acidentalmente contaminado com solução sulfocrômica Crhomium redox specification in soil accidentally contamined with sulphochrinuc solution

    Directory of Open Access Journals (Sweden)

    Wladiana Oliveira Matos

    2008-01-01

    Full Text Available Determination of Cr(VI and Cr(III was studied in soil samples accidentally contaminated with sulphochromic solution. Molecular absorption spectrophotometry based on the diphenylcarbazide method was used for the determination of Cr(VI after its alkaline extraction. The total chromium concentration was determined using ICP OES. The quantification of Cr(III was accomplished by subtracting the Cr(VI concentration from the total chromium concentration. Regardless of the known contamination of the soil samples by sulphochromic solution, concentrations of Cr(VI were below the detection limit. Addition and recovery experiments for Cr(VI in soil samples with and without organic matter indicated its influence on the reduction of Cr(VI to Cr(III.

  15. Evaluation of herbicidal potential of depsides from Cladosporium uredinicola, an endophytic fungus found in Guava fruit

    Energy Technology Data Exchange (ETDEWEB)

    Medeiros, Livia S. de; Sampaio, Olivia M.; Silva, Maria Fatima das G.F. da; Rodrigues Filho, Edson [Departamento de Quimica, Universidade Federal de Sao Carlos, SP (Brazil); Veiga, Thiago Andre M., E-mail: tveiga@unifesp.br [Instituto de Ciencias Ambientais, Quimicas e Farmaceuticas, Universidade Federal de Sao Paulo, Diadema, SP (Brazil)

    2012-08-15

    Two natural products produced by Cladosporium uredinicola, an endophytic fungus isolated from guava fruit, were evaluated for their effects on photosynthesis. Both of them inhibited electron flow (basal, phosphorylating, and uncoupled) from water to methylviologen (MV), acting as Hill reaction inhibitors in freshly lysed spinach thylakoids. These polyketides, belonging to depsides class, inhibited partial reactions of photosystem II (PS II) electron flow from water to 2,5-dichloro-1,4-benzoquinone (DCBQ), from water to sodium silicomolybdate (SiMo Na{sup +}), and partially inhibited electron flow from 1,5-diphenylcarbazide (DPC) to 2,6-dichloroindophenol (DCPIP). These results established that the depsides sites of inhibition are located on the donor and acceptor sides of PS II, between P680 and QA . Chlorophyll a fluorescence measurements corroborated this mechanism of action. None of the tested compounds inhibited photosystem I (PS I) electron transport. (author)

  16. Inhibitory effect of some carbazides on corrosion of aluminium in hydrochloric acid and sodium hydroxide solutions

    Energy Technology Data Exchange (ETDEWEB)

    Fouda, A.S. [El-Mansoura Univ. (Egypt). Dept. of Chemistry; Madkour, L.H. [Tanta Univ. (Egypt). Dept. of Chemistry; Elshafei, A.A. [El-Mansoura Univ. (Egypt). Dept. of Chemistry; Elasklany, A.H. [El-Mansoura Univ. (Egypt). Dept. of Chemistry

    1995-06-01

    The dissolution of aluminium in hydrochloric acid and sodium hydroxide solutions in the presence of semicarbazide, thiosemicarbazide and sym.diphenylcarbazide as corrosion inhibitors has been studied using thermometric, weight-loss and polarization methods. The three methods gave consistent results. The higher inhibition efficiency of these compounds in acidic than in alkaline madia may be due to the less negative potential of aluminium in hydrochloric acid solution, favouring adsorption of the additive. The adsorption of these compounds were found to obey Frumkin adsorption isotherm. Cathodic polarization measurements showed that these compounds are cathodic inhibitors and their adsorption in the double layer does not change the mechanism of the hydrogen evolution reaction. The results are analysed in terms of both molecular and cationic adsorption. (orig.)

  17. Microfluidic Paper-based Analytical Device for the Determination of Hexavalent Chromium by Photolithographic Fabrication Using a Photomask Printed with 3D Printer.

    Science.gov (United States)

    Asano, Hitoshi; Shiraishi, Yukihide

    2018-01-01

    This article describes a simple and inexpensive microfluidic paper-based analytical device (μPAD) for the determination of hexavalent chromium (Cr VI ) in water samples. The μPADs were fabricated on paper by photolithography using a photomask printed with a 3D printer and functionalized with reagents for a colorimetric assay. In the μPAD, Cr VI reacts with 1,5-diphenylcarbazide to form a violet-colored complex. Images of μPADs were captured with a digital camera; then the red, green, and blue color intensity of each detection zone were measured using images processing software. The green intensity analysis was the best sensitive among the RGB color. A linear working range (40 - 400 ppm; R 2 = 0.981) between the Cr VI and green intensity was obtained with a detection limit of 30 ppm. All of the recoveries were between 94 and 109% in recovery studies on water samples, and good results were obtained.

  18. Salt-assisted liquid-liquid microextraction of Cr(VI) ion using an ionic liquid for preconcentration prior to its determination by flame atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Majidi, B.; Shemirani, F.

    2012-01-01

    We report on the salt-assisted liquid-liquid microextraction of cationic complexes of Cr(VI) ion using the hydrophilic ionic liquid (IL) 1-butyl-3-methylimidazolium tetrafluoraborate and potassium hydrogen phosphate. This is a novel, simple, non-toxic and effective technique for sample pretreatment technique that displays large extraction efficiency and represents a new platform where Cr(VI) is complexed with 1,5-diphenylcarbazide (DPC) in sulfuric acid medium. It was applied to the extraction of Cr(VI) in the form of the Cr(VI)-DPC complex prior to its determination by flame atomic absorption spectrometry. Cr(III) ion also can be determined by this procedure after oxidation to Cr(VI). Extraction is mainly affected by the amount of water-soluble IL, the kind and quantity of inorganic salts, by pH and the concentration of DPC. Calibration plots are linear in the range from 3 to 150 μg L -1 of Cr(VI), and the limit of detection is 1. 25 μg L -1 . The method was successfully applied to the speciation and determination of trace levels of Cr(III) and Cr(VI) in environmental water samples containing high levels of dissolved salts or food grade salts. (author)

  19. Determination of nanomolar chromate in drinking water with solid phase extraction and a portable spectrophotometer.

    Science.gov (United States)

    Ma, Jian; Yang, Bo; Byrne, Robert H

    2012-06-15

    Determination of chromate at low concentration levels in drinking water is an important analytical objective for both human health and environmental science. Here we report the use of solid phase extraction (SPE) in combination with a custom-made portable light-emitting diode (LED) spectrophotometer to achieve detection of chromate in the field at nanomolar levels. The measurement chemistry is based on a highly selective reaction between 1,5-diphenylcarbazide (DPC) and chromate under acidic conditions. The Cr-DPC complex formed in the reaction can be extracted on a commercial C18 SPE cartridge. Concentrated Cr-DPC is subsequently eluted with methanol and detected by spectrophotometry. Optimization of analytical conditions involved investigation of reagent compositions and concentrations, eluent type, flow rate (sample loading), sample volume, and stability of the SPE cartridge. Under optimized conditions, detection limits are on the order of 3 nM. Only 50 mL of sample is required for an analysis, and total analysis time is around 10 min. The targeted analytical range of 0-500 nM can be easily extended by changing the sample volume. Compared to previous SPE-based spectrophotometric methods, this analytical procedure offers the benefits of improved sensitivity, reduced sample consumption, shorter analysis time, greater operational convenience, and lower cost. Copyright © 2012 Elsevier B.V. All rights reserved.

  20. Spectrophotometric Quantification of Toxicologically Relevant Concentrations of Chromium(VI in Cosmetic Pigments and Eyeshadow Using Synthetic Lachrymal Fluid Extraction

    Directory of Open Access Journals (Sweden)

    Sarah Wurster

    2012-01-01

    Full Text Available Chromium(VI salts are possible contaminants of the chromium(III pigments used as colorants in eyeshadow preparations. The use of products containing these contaminants poses acute risks for sensitization and contact allergies. Chromium(VI compounds are also classified as carcinogenic to humans (IARC group 1. An analytical method to analyse trace levels of chromium(VI in eyeshadow was developed in this study. The method is based on an extraction of the chromium(VI from the sample using a maximum extraction with alkali and additionally with synthetic lachrymal fluid to simulate physiological conditions. Following derivatization with 1,5-diphenylcarbazide, the extracted chromium(VI is then quantified by spectrophotometry (540 nm. Validation tests indicated a method standard deviation (inter- and intraday of 8.7% and a linear range up to 25 mg/kg. The average recovery was 107.9%, and the detection limit was 2.7 mg/kg. The applicability of the procedure was confirmed by the analysis of pigments and authentic eyeshadow matrices.

  1. Groundwater contaminated with hexavalent chromium [Cr (VI]: a health survey and clinical examination of community inhabitants (Kanpur, India.

    Directory of Open Access Journals (Sweden)

    Priti Sharma

    Full Text Available BACKGROUND: We assessed the health effects of hexavalent chromium groundwater contamination (from tanneries and chrome sulfate manufacturing in Kanpur, India. METHODS: The health status of residents living in areas with high Cr (VI groundwater contamination (N = 186 were compared to residents with similar social and demographic features living in communities having no elevated Cr (VI levels (N = 230. Subjects were recruited at health camps in both the areas. Health status was evaluated with health questionnaires, spirometry and blood hematology measures. Cr (VI was measured in groundwater samples by diphenylcarbazide reagent method. RESULTS: Residents from communities with known Cr (VI contamination had more self-reports of digestive and dermatological disorders and hematological abnormalities. GI distress was reported in 39.2% vs. 17.2% males (AOR = 3.1 and 39.3% vs. 21% females (AOR = 2.44; skin abnormalities in 24.5% vs. 9.2% males (AOR = 3.48 and 25% vs. 4.9% females (AOR = 6.57. Residents from affected communities had greater RBCs (among 30.7% males and 46.1% females, lower MCVs (among 62.8% males and less platelets (among 68% males and 72% females than matched controls. There were no differences in leucocytes count and spirometry parameters. CONCLUSIONS: Living in communities with Cr (VI groundwater is associated with gastrointestinal and dermatological complaints and abnormal hematological function. Limitations of this study include small sample size and the lack of long term follow-up.

  2. Groundwater contaminated with hexavalent chromium [Cr (VI)]: a health survey and clinical examination of community inhabitants (Kanpur, India).

    Science.gov (United States)

    Sharma, Priti; Bihari, Vipin; Agarwal, Sudhir K; Verma, Vipin; Kesavachandran, Chandrasekharan N; Pangtey, Balram S; Mathur, Neeraj; Singh, Kunwar Pal; Srivastava, Mithlesh; Goel, Sudhir K

    2012-01-01

    We assessed the health effects of hexavalent chromium groundwater contamination (from tanneries and chrome sulfate manufacturing) in Kanpur, India. The health status of residents living in areas with high Cr (VI) groundwater contamination (N = 186) were compared to residents with similar social and demographic features living in communities having no elevated Cr (VI) levels (N = 230). Subjects were recruited at health camps in both the areas. Health status was evaluated with health questionnaires, spirometry and blood hematology measures. Cr (VI) was measured in groundwater samples by diphenylcarbazide reagent method. Residents from communities with known Cr (VI) contamination had more self-reports of digestive and dermatological disorders and hematological abnormalities. GI distress was reported in 39.2% vs. 17.2% males (AOR = 3.1) and 39.3% vs. 21% females (AOR = 2.44); skin abnormalities in 24.5% vs. 9.2% males (AOR = 3.48) and 25% vs. 4.9% females (AOR = 6.57). Residents from affected communities had greater RBCs (among 30.7% males and 46.1% females), lower MCVs (among 62.8% males) and less platelets (among 68% males and 72% females) than matched controls. There were no differences in leucocytes count and spirometry parameters. Living in communities with Cr (VI) groundwater is associated with gastrointestinal and dermatological complaints and abnormal hematological function. Limitations of this study include small sample size and the lack of long term follow-up.

  3. Correlation between bulk- and surface chemistry of Cr-tanned leather and the release of Cr(III) and Cr(VI).

    Science.gov (United States)

    Hedberg, Yolanda S; Lidén, Carola; Odnevall Wallinder, Inger

    2014-09-15

    About 1-3% of the adult general population in Europe is allergic to chromium (Cr). The assessment of the potential release of Cr(III) and Cr(VI) from leather is hence important from a human health and environmental risk perspective. The Cr(VI) content in leather was recently restricted in the European Union. The aim of this study was to assess possible correlations between the bulk and surface chemistry of leather, released Cr(III) and Cr(VI), and capacities of co-released leather specific species to reduce and complex released Cr. Four differently tanned leathers were characterized by scanning electron microscopy with energy dispersive spectroscopy, X-ray photoelectron spectroscopy, attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, and the diphenylcarbazide colorimetric method. Their characteristics were compared with results on Cr(III) and Cr(VI) release into artificial sweat (ASW, pHleather-specific species were shown to reduce Cr(VI), both in ASW and in PB. Their reduction capacities correlated with findings of the surface content of Cr and of released Cr. Leather samples without this capacity, and with less aromatic surface groups visible by ATR-FTIR, revealed Cr(VI) both at the surface and in solution (PB). Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.

  4. Chromium(III) release from chromium‐tanned leather elicits allergic contact dermatitis: a use test study

    Science.gov (United States)

    Erfani, Behnaz; Matura, Mihály; Lidén, Carola

    2018-01-01

    Summary Background Chromium (Cr) is a common skin sensitizer. The use of Cr(VI) in leather is restricted in the EU, but that of Cr(III) is not. Objectives To assess whether prolonged exposure to Cr‐tanned leather with mainly Cr(III) release may elicit allergic contact dermatitis in Cr‐allergic individuals. Method Ten Cr‐allergic subjects and 22 controls were patch tested with serial dilutions of Cr(III) and Cr(VI), and with leather samples. They then conducted a use test with a Cr‐tanned and a Cr‐free leather bracelet over a period of 3 weeks, for 12 h per day. Cr deposited on the skin from the bracelets was measured in the controls, and the diphenylcarbazide test for Cr(VI) and extraction tests for Cr(III) and Cr(VI) were conducted for the different leathers. Results Four of 10 Cr‐allergic subjects developed positive reactions to the Cr‐tanned bracelet within 7–21 days, whereas only 1 of 10 had a positive patch test reaction to this leather. Cr released from the Cr‐tanned leather was most probably entirely Cr(III), with a quantifiable amount being deposited on the skin. Conclusions This study strongly suggests that prolonged and repeated exposure to Cr‐tanned leather with mainly Cr(III) release is capable of eliciting allergic contact dermatitis in Cr‐allergic individuals. PMID:29322530

  5. A polyaniline-magnetite nanocomposite as an anion exchange sorbent for solid-phase extraction of chromium(VI) ions

    International Nuclear Information System (INIS)

    Rezvani, Mehdi; Asgharinezhad, Ali Akbar; Ebrahimzadeh, Homeira; Shekari, Nafiseh

    2014-01-01

    This work describes a novel polyaniline-magnetite nanocomposite and its application to the preconcentration of Cr(VI) anions. The material was obtained by oxidative polymerization of aniline in the presence of magnetite nanoparticles. The parameters affecting preconcentration were optimized by a Box-Behnken design through response surface methodology. Extraction time, amount of magnetic sorbent and pH value were selected as the main factors affecting sorption. The sorption capacity of the sorbent for Cr(VI) is 54 mg g −1 . The type, volume and concentration of the eluents, and the elution time were selected as main factors in the optimization study of the elution step. Following sorption and elution, the Cr(VI) ions were reacted with diphenylcarbazide, and the resulting dye was quantified by HPLC with optical detection at 546 nm. The limit of detection is 0.1 μg L −1 , and all the relative standard deviations are <6.3 %. The nanocomposite was successfully applied to the rapid extraction and determination of trace quantities of Cr(VI) ions in spiked water samples. (author)

  6. Chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of nuclear-grade uranyl nitrate solutions

    International Nuclear Information System (INIS)

    Anon.

    1981-01-01

    The standard covers analytical procedures to determine compliance of nuclear-grade uranyl nitrate solution to specifications. The following methods are described in detail: uranium by ferrous sulfate reduction-potassium dichromate titrimetry and by ignition gravimetry; specific gravity by pycnometry; free acid by oxalate complexation; thorium by the Arsenazo(III) (photometric) method; chromium by the diphenylcarbazide (photometric) method; molybdenum by the thiocyanate (photometric) method; halogens separation by steam distillation; fluorine by specific ion electrode; halogen distillate analysis: chloride, bromide and iodide by amperometric microtitrimetry; bromine by the fluorescein (photometric) method; sulfate sulfur by (photometric) turbidimetry; phosphorus by the molybdenum blue (photometric) method; silicon by the molybdenum blue (photometric) method; carbon by persulfate oxidation-acid titrimetry; nonvolatile impurities by spectrography; volatile impurities by rotating-disk spark spectrography; boron by emission spectrography; impurity elements by spark source mass spectrography; isotopic composition by multiple filament surface-ionization mass spectrometry; uranium-232 by alpha spectrometry; total alpha activity by direct alpha counting; fission product activity by beta and gamma counting; entrained organic matter by infrared spectrophotometry

  7. Spectrophotometric Determination of Chromium (III) in Egyptian 11 manite from phosphate solution using Ewes as a selective adsorbent

    International Nuclear Information System (INIS)

    Abdu, A. A.

    2012-12-01

    Egyptian white sand (EWS) was used as an adsorbent for the selective separation of Cr(III) from phosphate solution to be determined colorimetrically using 1,5-diphenylcarbazide. The experimental factors affecting maximum selective adsorption/desorption of Cr(III) on / from EWS were the amount of adsorption (g), pH of initial concentration of Cr(III) in solution, contact time temperature and initial concentration of Cr(III) in solution were investigated. No effect of [PO 4 ] 3- , Ti(IV) and Fe(III) on Cr(III) sorption were verified. Accuracy and relative standard deviations (RSD) were acceptable for all analyses. The maximum sorption capacity, Q e , of adsorbed Cr(III) per gram of sand was 93.5 mg/g, at EWS concentration 20 g/1, pH 0.8 contact time 120 min and temperature 30 o C for adsorption of Cr(III) on EWS and pH 0.4, contact time 6 min and temperature 25o C for desorption of Cr(III) from EWS. (Author)

  8. In-syringe magnetic-stirring-assisted liquid-liquid microextraction for the spectrophotometric determination of Cr(VI) in waters.

    Science.gov (United States)

    Henríquez, Camelia; Horstkotte, Burkhard; Solich, Petr; Cerdà, Víctor

    2013-08-01

    A fully automated method for the determination of chromate is described. It is based on the selective reaction of Cr(VI) with diphenylcarbazide in acidic media to form a colored complex of Cr(III) with the oxidation product diphenylcarbazone. The reaction was performed within the syringe of an automatic burette containing a magnetic stirrer for homogenization of the sample and the required reagents. In-syringe stirring was made possible using a specially designed driving device placed around the syringe barrel to achieve a rotating magnetic field in the syringe, forcing the stirrer to spin. In a second step, the reaction mixture in the syringe was neutralized to allow in-syringe magnetic-stirring-assisted dispersive liquid-liquid microextraction of the complex into 125 μL of n-hexanol. After phase separation by droplet flotation over 30 s, the organic phase was propelled into a coupled spectrophotometric detection cell. The entire multistep procedure including in-system standard preparation was done within 270 s. The method was used for the analysis of natural waters, achieving average analyte recovery of 103%, a limit of detection of 0.26 μg L(-1), and a repeatability of less than 4% relative standard deviation.

  9. Environmental impacts of Sheba tannery (Ethiopia effluents on the surrounding water bodies

    Directory of Open Access Journals (Sweden)

    Abraha Gebrekidan

    2009-08-01

    Full Text Available The levels of hexavalent chromium from direct and treated Sheba tannery effluents, downstream river and spring water samples and upstream river water samples were determined spectrophotometrically by the s-diphenylcarbazide method at 540 nm. Temporal and representative samples were collected from the untreated tannery effluent (S1, sedimentation pond (S2, chromium oxidation pond (S3, downstream river (S4, downstream spring (S5 and 5 kms upstream river (S6. The mean levels of hexavalent chromium in S1, S2, S3, S4, S5 and S6 were 10.54, 9.15, 7.82, 0.58, 0.54 and 0.015 mg/L, respectively. The levels of hexavalent chromium in the downstream river and spring water samples exceed the World Health Organization (WHO permissible limit of total chromium in drinking waters (0.05 mg/L as opposed to the levels in the upstream waters. The increased concentrations of Cr(VI in the water samples indicate the possible environmental pollution of the downstream water bodies by the Sheba tannery effluents. In view of the toxicity and related environmental hazards, the levels of hexavalent chromium from the Sheba tannery effluents must be reduced to a permissible limit before discharging into the down stream waters being used for domestic purposes by the nearby communities.

  10. Selective sampling and measurement of Cr (VI) in water with polyquaternary ammonium salt as a binding agent in diffusive gradients in thin-films technique.

    Science.gov (United States)

    Chen, Hong; Zhang, Yang-Yang; Zhong, Ke-Li; Guo, Lian-Wen; Gu, Jia-Li; Bo, Le; Zhang, Meng-Han; Li, Jian-Rong

    2014-04-30

    A diffusive gradients in thin films (DGT) device with polyquaternary ammonium salt (PQAS) as a novel binding agent (PQAS DGT) combined with graphite furnace atomic absorption spectrometry (GFAAS) was developed for the selective sampling and measurement of Cr (VI) in water. The performance of PQAS DGT was independent of pH 3-12 and ionic strength from 1 × 10(-3) to 1 molL(-1). DGT validation experiments showed that Cr (VI) was measured accurately as well as selectively by PQAS DGT, whereas Cr (III) was not determined quantitatively. Compared with diphenylcarbazide spectrophotometric method (DPC), the measurement of Cr (VI) with PQAS DGT was agreement with that of DPC method in the industrial wastewater. PQAS-DGT device had been successfully deployed in local freshwater. The concentrations of Cr (VI) determined by PQAS DGT coupled with GFAAS in Nuer River, Ling River and North Lake were 0.73 ± 0.09 μg L(-1), 0.50 ± 0.07 μg L(-1) and 0.61 ± 0.07 μg L(-1), respectively. The results indicate that PQAS DGT device can be used for the selective sampling and measurement Cr (VI) in water and its detection limit is lower than that of DPC method. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Application of coals as sorbents for the removal of Cr from aqueous waste streams

    Energy Technology Data Exchange (ETDEWEB)

    Lakatos, J.; Brown, S.D.; Snape, C.E. [University of Miskolc, Miskolc (Hungary). Dept. of Analytical Chemistry

    2001-09-01

    The study reported further understanding of how various electron transfer processes operate for Cr(VI) with a view to using coals for the removal of Cr(VI) from waste streams. Skye peat, Spanish and German lignites, UK high and low volatility bituminous coals and an activated carbon were used. After treatment to remove exchangeable cations, ion exchange experiments were conducted in 0.1 M acetic acid-sodium acetate (1:1) buffer and 0.05 M sulphuric acid solutions and the slurries were agitated once a day. The ion concentrations in the solutions were determined by flame atomic absorption spectroscopy. The Cr(VI) renaming in solution was determined by the standard calorimetric 1,5-diphenylcarbazide method. Peat and low rank (Spanish Mequinenza) coal exhibited a larger capacity for Cr(VI) removal than bituminous coal. Redox mechanisms are operative coupled with the oxidation of the coal and peat surfaces. Desorption of Cr(III) formed by reduction which occurs in strongly acidic media also needs to be considered. 1 ref., 3 figs.

  12. Correlation between bulk- and surface chemistry of Cr-tanned leather and the release of Cr(III) and Cr(VI)

    Energy Technology Data Exchange (ETDEWEB)

    Hedberg, Yolanda S., E-mail: yolanda@kth.se [KTH Royal Institute of Technology, School of Chemical Science and Engineering, Department of Chemistry, Division of Surface and Corrosion Science, SE-10044 Stockholm (Sweden); Institute of Environmental Medicine, Karolinska Institutet, Box 210, SE-17177 Stockholm (Sweden); Lidén, Carola, E-mail: carola.liden@ki.se [Institute of Environmental Medicine, Karolinska Institutet, Box 210, SE-17177 Stockholm (Sweden); Odnevall Wallinder, Inger, E-mail: ingero@kth.se [KTH Royal Institute of Technology, School of Chemical Science and Engineering, Department of Chemistry, Division of Surface and Corrosion Science, SE-10044 Stockholm (Sweden)

    2014-09-15

    Graphical abstract: - Highlights: • Released reducing/complexing leather-specific species can reduce released Cr(VI). • No co-released species enable the formation of Cr(VI) in solution. • The major Cr species released from leather in phosphate buffer was Cr(III) (>82%). • No Cr(VI) was released into artificial sweat. - Abstract: About 1–3% of the adult general population in Europe is allergic to chromium (Cr). The assessment of the potential release of Cr(III) and Cr(VI) from leather is hence important from a human health and environmental risk perspective. The Cr(VI) content in leather was recently restricted in the European Union. The aim of this study was to assess possible correlations between the bulk and surface chemistry of leather, released Cr(III) and Cr(VI), and capacities of co-released leather specific species to reduce and complex released Cr. Four differently tanned leathers were characterized by scanning electron microscopy with energy dispersive spectroscopy, X-ray photoelectron spectroscopy, attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, and the diphenylcarbazide colorimetric method. Their characteristics were compared with results on Cr(III) and Cr(VI) release into artificial sweat (ASW, pH < 6.5) and phosphate buffer (PB, pH 7.5–8.0), measured by means of spectrophotometry and atomic absorption spectroscopy. Co-released leather-specific species were shown to reduce Cr(VI), both in ASW and in PB. Their reduction capacities correlated with findings of the surface content of Cr and of released Cr. Leather samples without this capacity, and with less aromatic surface groups visible by ATR-FTIR, revealed Cr(VI) both at the surface and in solution (PB)

  13. A microfluidic paper-based analytical device for rapid quantification of particulate chromium

    International Nuclear Information System (INIS)

    Rattanarat, Poomrat; Dungchai, Wijitar; Cate, David M.; Siangproh, Weena; Volckens, John; Chailapakul, Orawon; Henry, Charles S.

    2013-01-01

    Graphical abstract: -- Highlights: •Cr detection using a paper-based analytical device. •Analysis of total Cr levels in particulate matter was achieved. •Method for on-paper oxidation of Cr to Cr(VI) using Ce(IV) was established. -- Abstract: Occupational exposure to Cr is concerning because of its myriad of health effects. Assessing chromium exposure is also cost and resource intensive because the analysis typically uses sophisticated instrumental techniques like inductively coupled plasma-mass spectrometry (ICP-MS). Here, we report a novel, simple, inexpensive microfluidic paper-based analytical device (μPAD) for measuring total Cr in airborne particulate matter. In the μPAD, tetravalent cerium (Ce(IV)) was used in a pretreatment zone to oxidize all soluble Cr to Cr(VI). After elution to the detection zone, Cr(VI) reacts with 1,5-diphenylcarbazide (1,5-DPC) forming 1,5-diphenylcarbazone (DPCO) and Cr(III). The resulting Cr(III) forms a distinct purple colored complex with the DPCO. As proof-of-principle, particulate matter (PM) collected on a sample filter was analyzed with the μPAD to quantify the mass of total Cr. A log-linear working range (0.23–3.75 μg; r 2 = 0.998) between Cr and color intensity was obtained with a detection limit of 0.12 μg. For validation, a certified reference containing multiple competing metals was analyzed. Quantitative agreement was obtained between known Cr levels in the sample and the Cr measured using the μPAD

  14. Chromium(III) and chromium(VI) release from leather during 8 months of simulated use.

    Science.gov (United States)

    Hedberg, Yolanda S; Lidén, Carola

    2016-08-01

    Chromium (Cr) release from Cr-tanned leather articles is a major cause of Cr contact dermatitis. It has been suggested that Cr(VI) release from leather is not necessarily an intrinsic property of the leather, but is strongly dependent on environmental conditions. To test this hypothesis for long-term (8 months) simulated use. The release of total Cr and Cr(VI) from Cr-tanned, unfinished leather was analysed in subsequent phosphate buffer (pH 8.0) immersions for a period of 7.5 months. The effect of combined ultraviolet treatment and alkaline solution (pH 12.1) was tested. Dry storage [20% relative humidity (RH)] was maintained between immersions. Atomic absorption spectroscopy, X-ray fluorescence and diphenylcarbazide tests were used. Cr(VI) release was dependent on previous dry storage or alkaline treatment, but not on duration or number of previous immersions. Cr(III) release decreased with time. Fifty-two percent of the total Cr released during the last immersion period was Cr(VI). Cr(VI) release exceeded 9 mg/kg in all immersion periods except in the first 10-day immersion (2.6 mg/kg). Cr(VI) release is primarily determined by environmental factors (RH prior to immersion, solution pH, and antioxidant content). The RH should be kept low prior to testing Cr(VI) release from leather. © 2016 The Authors. Contact Dermatitis published by John Wiley & Sons Ltd.

  15. Determination of hexavalent chromium in exhaled breath condensate and environmental air among chrome plating workers.

    Science.gov (United States)

    Goldoni, Matteo; Caglieri, Andrea; Poli, Diana; Vettori, Maria Vittoria; Corradi, Massimo; Apostoli, Pietro; Mutti, Antonio

    2006-03-15

    Chromium speciation has attracted attention because of the different toxicity of Cr(III), which is considered relatively non-toxic, and Cr(VI), which can cross cell membranes mainly as a chromate anion and has been classified as a class I human carcinogen. The aims of the present study were to measure soluble Cr(VI) levels in environmental samples, to develop a simple method of quantifying Cr(VI) in exhaled breath condensate (EBC), and to follow the kinetics of EBC Cr(VI) in chrome plating workers.Personal air samples were collected from 10 chrome platers; EBC was collected from the same workers immediately after the work shift on Tuesday and before the work shift on the following Wednesday. Environmental and EBC Cr(VI) levels were determined by means of colorimetry and electrothermal absorption atomic spectrometry, respectively.The method of detecting Cr(VI) in environmental air was based on the extraction of the Cr(VI)-diphenylcarbazide (Cr(VI)-DPC) complex in 1-butanol, whereas EBC Cr(VI) was determined using a solvent extraction of Cr(VI) as an ion pair with tetrabutylammonium ion, and subsequent direct determination of the complex (Cr(VI)-DPC) in EBC.Kinetic data showed that airborne Cr(VI) was reduced by 50% in airway lining fluid sampled at the end of exposure and that there was a further 50% reduction after about 15 h. The persistence of Cr(VI) in EBC supports the use of EBC in assessing target tissue levels of Cr(VI).

  16. Determination of hexavalent chromium in exhaled breath condensate and environmental air among chrome plating workers

    International Nuclear Information System (INIS)

    Goldoni, Matteo; Caglieri, Andrea; Poli, Diana; Vettori, Maria Vittoria; Corradi, Massimo; Apostoli, Pietro; Mutti, Antonio

    2006-01-01

    Chromium speciation has attracted attention because of the different toxicity of Cr(III), which is considered relatively non-toxic, and Cr(VI), which can cross cell membranes mainly as a chromate anion and has been classified as a class I human carcinogen. The aims of the present study were to measure soluble Cr(VI) levels in environmental samples, to develop a simple method of quantifying Cr(VI) in exhaled breath condensate (EBC), and to follow the kinetics of EBC Cr(VI) in chrome plating workers. Personal air samples were collected from 10 chrome platers; EBC was collected from the same workers immediately after the work shift on Tuesday and before the work shift on the following Wednesday. Environmental and EBC Cr(VI) levels were determined by means of colorimetry and electrothermal absorption atomic spectrometry, respectively. The method of detecting Cr(VI) in environmental air was based on the extraction of the Cr(VI)-diphenylcarbazide (Cr(VI)-DPC) complex in 1-butanol, whereas EBC Cr(VI) was determined using a solvent extraction of Cr(VI) as an ion pair with tetrabutylammonium ion, and subsequent direct determination of the complex (Cr(VI)-DPC) in EBC. Kinetic data showed that airborne Cr(VI) was reduced by 50% in airway lining fluid sampled at the end of exposure and that there was a further 50% reduction after about 15 h. The persistence of Cr(VI) in EBC supports the use of EBC in assessing target tissue levels of Cr(VI)

  17. Determination of hexavalent chromium in exhaled breath condensate and environmental air among chrome plating workers

    Energy Technology Data Exchange (ETDEWEB)

    Goldoni, Matteo [Laboratory of Industrial Toxicology, Department of Clinical Medicine, Nephrology and Health Sciences, University of Parma, Via Gramsci 14, 43100 Parma (Italy); National Institute of Occupational Safety and Prevention, Research Centre at University of Parma, Parma (Italy); Caglieri, Andrea [Laboratory of Industrial Toxicology, Department of Clinical Medicine, Nephrology and Health Sciences, University of Parma, Via Gramsci 14, 43100 Parma (Italy); Poli, Diana [Laboratory of Industrial Toxicology, Department of Clinical Medicine, Nephrology and Health Sciences, University of Parma, Via Gramsci 14, 43100 Parma (Italy); National Institute of Occupational Safety and Prevention, Research Centre at University of Parma, Parma (Italy); Vettori, Maria Vittoria [Laboratory of Industrial Toxicology, Department of Clinical Medicine, Nephrology and Health Sciences, University of Parma, Via Gramsci 14, 43100 Parma (Italy); National Institute of Occupational Safety and Prevention, Research Centre at University of Parma, Parma (Italy); Corradi, Massimo [Laboratory of Industrial Toxicology, Department of Clinical Medicine, Nephrology and Health Sciences, University of Parma, Via Gramsci 14, 43100 Parma (Italy); National Institute of Occupational Safety and Prevention, Research Centre at University of Parma, Parma (Italy); Apostoli, Pietro [Laboratory of Industrial Hygiene, Department of Experimental and Applied Medicine, University of Brescia (Italy); Mutti, Antonio [Laboratory of Industrial Toxicology, Department of Clinical Medicine, Nephrology and Health Sciences, University of Parma, Via Gramsci 14, 43100 Parma (Italy)]. E-mail: antonio.mutti@unipr.it

    2006-03-15

    Chromium speciation has attracted attention because of the different toxicity of Cr(III), which is considered relatively non-toxic, and Cr(VI), which can cross cell membranes mainly as a chromate anion and has been classified as a class I human carcinogen. The aims of the present study were to measure soluble Cr(VI) levels in environmental samples, to develop a simple method of quantifying Cr(VI) in exhaled breath condensate (EBC), and to follow the kinetics of EBC Cr(VI) in chrome plating workers. Personal air samples were collected from 10 chrome platers; EBC was collected from the same workers immediately after the work shift on Tuesday and before the work shift on the following Wednesday. Environmental and EBC Cr(VI) levels were determined by means of colorimetry and electrothermal absorption atomic spectrometry, respectively. The method of detecting Cr(VI) in environmental air was based on the extraction of the Cr(VI)-diphenylcarbazide (Cr(VI)-DPC) complex in 1-butanol, whereas EBC Cr(VI) was determined using a solvent extraction of Cr(VI) as an ion pair with tetrabutylammonium ion, and subsequent direct determination of the complex (Cr(VI)-DPC) in EBC. Kinetic data showed that airborne Cr(VI) was reduced by 50% in airway lining fluid sampled at the end of exposure and that there was a further 50% reduction after about 15 h. The persistence of Cr(VI) in EBC supports the use of EBC in assessing target tissue levels of Cr(VI)

  18. Study of cis- and trans-uranium elements by paper chromatography and electrophoresis

    International Nuclear Information System (INIS)

    Clanet, F.

    1968-01-01

    In this work, the field of application of paper chromatography and electrophoresis in inorganic chemistry has been extended to elements 90 to 96 in hydrochloric and nitric acid solution. Results obtained concern the following points: 1) - Characterization of the valency states of Np and of Pu using coloured reactions on chromatograms and electrophoregrams. The valency IV is characterized by alizarin, arsenazo-I and thorin-I, whilst diphenylcarbazide is used for the hexavalent state. 2) - Paper chromatography: by using as eluent, mixtures of equal parts of aqueous HCl and HNO 3 solutions and of alcohols (methanol, ethanol and n-butanol), the R f values of elements 90 to 96 have been determined. It has been possible to deduce certain conclusions concerning the complexing of these elements by Cl - and NO 3 - ions. 3) - We have developed an electrophoretic technique on cellulose acetate membranes in order to separate the charged species formed by the elements 90 to 96 in HCl and HNO 3 solutions from 1 to 12 M. Mobility curves have been obtained. It appears from our results that the tendency for the elements considered to form anionic complexes follows the order of the ionic potentials when the valency state is four; this order is reversed for the valency three. The ions Cl - have a smaller tendency to form complexes than the NO 3 - ions with respect to these elements in their oxidation state III or IV, but the reverse phenomenon is observed for U VI and Pu VI . Finally, the complexing of the cations Pu 4+ and PuUO 2 2+ by NO 3 - follows the order of the ionic potentials but occurs in the reverse order for Cl - ions. 4) - Various analytical applications are considered: separation of the various elements from each other and separation of the valency states of Np and of Pu. (author) [fr

  19. Determination of hexavalent chromium concentration in industrial waste incinerator stack gas by using a modified ion chromatography with post-column derivatization method.

    Science.gov (United States)

    Miyake, Yuichi; Tokumura, Masahiro; Iwazaki, Yuta; Wang, Qi; Amagai, Takashi; Horii, Yuichi; Otsuka, Hideyuki; Tanikawa, Noboru; Kobayashi, Takeshi; Oguchi, Masahiro

    2017-06-16

    An ion chromatography with post-column derivatization with 1,5-diphenylcarbazide (IC-DPC) analytical method was modified to enable measurement of trace-level hexavalent chromium (Cr(VI)) in air. One of the difficulties in determining trace levels of Cr(VI) in air with conventional IC-DPC methods is co-elution of the solvent and ion peaks due to high concentrations of ionic compounds in the extract. However, by using gradient elution rather than isocratic elution we were able to fully resolve the Cr(VI) ion peak from the solvent peak without the need for diluting the extract, which would have reduced the minimum quantifiable level of the method. With this method, we were able to detect Cr(VI) in air at concentrations of 5.3ng/m 3 (assuming a sampling volume of 1m 3 and a final solution volume of 10mL). Recovery tests at three different concentrations of Cr(VI) (50, 250, 1000ng) were performed with or without fly ash; recovery rates at all the concentrations of Cr(VI), with or without fly ash, ranged from 68% to 110% (mean±relative standard deviation, 96%±11%), and there were no differences in recovery rates with respect to the presence or absence of fly ash. Finally, we used the developed method to determine the concentration of Cr(VI) in stack gases collected from eight industrial waste incinerators located in Japan. The concentration of Cr(VI) in the stack gases ranged from below the method quantification limit to 3100ng/m 3 . The highest concentrations of Cr(VI) detected in the stack gases were two to three orders of magnitude higher than that in ambient air in Japan. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Selective sampling and measurement of Cr (VI) in water with polyquaternary ammonium salt as a binding agent in diffusive gradients in thin-films technique

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Hong, E-mail: redastar@163.com [College of Chemistry, Chemical Engineering and Food Safety, Bohai University (China); Research Institute of Food Science, Bohai University (China); Food Safety Key Lab of Liaoning Province, Jinzhou 121013 (China); Zhang, Yang-Yang; Zhong, Ke-Li; Guo, Lian-Wen [College of Chemistry, Chemical Engineering and Food Safety, Bohai University (China); Research Institute of Food Science, Bohai University (China); Food Safety Key Lab of Liaoning Province, Jinzhou 121013 (China); Gu, Jia-Li [College of Chemistry, Chemical Engineering and Food Safety, Bohai University (China); Bo, Le; Zhang, Meng-Han [College of Chemistry, Chemical Engineering and Food Safety, Bohai University (China); Research Institute of Food Science, Bohai University (China); Food Safety Key Lab of Liaoning Province, Jinzhou 121013 (China); Li, Jian-Rong, E-mail: lijianrong@zjgsu.edu.cn [College of Chemistry, Chemical Engineering and Food Safety, Bohai University (China); Research Institute of Food Science, Bohai University (China); Food Safety Key Lab of Liaoning Province, Jinzhou 121013 (China)

    2014-04-01

    Graphical abstract: - Highlights: • We develop a new DGT device for in situ sampling Cr (VI) in water. • Polyquaternary ammonium salt (PQAS) was used as binding agent of DGT device. • Cr (VI) can be accumulated in the PQAS binding phase whereas Cr (III) cannot. • The DGT performance was independent of pH 3–12 and ionic strength 1 × 10{sup −3}–1 mol L{sup −1}. - Abstract: A diffusive gradients in thin films (DGT) device with polyquaternary ammonium salt (PQAS) as a novel binding agent (PQAS DGT) combined with graphite furnace atomic absorption spectrometry (GFAAS) was developed for the selective sampling and measurement of Cr (VI) in water. The performance of PQAS DGT was independent of pH 3–12 and ionic strength from 1 × 10{sup −3} to 1 mol L{sup −1}. DGT validation experiments showed that Cr (VI) was measured accurately as well as selectively by PQAS DGT, whereas Cr (III) was not determined quantitatively. Compared with diphenylcarbazide spectrophotometric method (DPC), the measurement of Cr (VI) with PQAS DGT was agreement with that of DPC method in the industrial wastewater. PQAS-DGT device had been successfully deployed in local freshwater. The concentrations of Cr (VI) determined by PQAS DGT coupled with GFAAS in Nuer River, Ling River and North Lake were 0.73 ± 0.09 μg L{sup −1}, 0.50 ± 0.07 μg L{sup −1} and 0.61 ± 0.07 μg L{sup −1}, respectively. The results indicate that PQAS DGT device can be used for the selective sampling and measurement Cr (VI) in water and its detection limit is lower than that of DPC method.

  1. Preparation of N-1 -naphthyl benzo- and N-phenyl benzo hydroxamic acids and study of their extractability towards Fe (III), Cr (VI) and U (VI)

    International Nuclear Information System (INIS)

    Mohamed, Eltoum Elnour

    1997-12-01

    Two aryl hydroxamic acids were prepared; The N-phenyl benzo hydroxamic acid and the N-1- naphthyl benzohydroxamic acid the first one was prepared by the partial reduction of nitrobenzene to the β-phenyl hydroxylamine and coupling the latter with benzyl chloride. The reduction was carried out using ammonium chloride and zinc dust; this pair failed after so many attempts to give the N-1- naphthyl hydroxylamine. So the latter was prepared by using a somewhat milder reducing agent; hydrogen sulphide and ammonia gas in absolute alcohol. The two acids were obtained using the modified procedure of Tandon coupling the hydroxylamine with benzoyl chloride. The two acids were characterized by their melting points, elemental analysis, their I.R functional group frequencies and by their characteristic colour tests with vanadium (VI) and Iron (III). The acids were used for the extraction and spectrophotometric determination for iron (III), Chromium (VI), and Uranium (VI) from different molar solution, PH and from synthetic sea water. The maximum recovery of iron (III) occurred at PH 4 and PH 5 giving 92.25 and 91.25% when using N-1-naphthyl benzo hydroxamic acid and a maximum recovery of 100% at PH 5 with other acid. The maximum recovery of Chromium (VI) occurred at 3MH 2 SO 4 of 97.50% when using N-1-naphthyl benzohydroxamic acid and a maximum of 94.25% at the same molar concentration with N-phenyl benzo hydroxamic acid. The maximum recovery for Uranium (VI) was occurred at PH 7 giving 100% when using N-1-naphthyl benzo hydroxamic acid and a maximum recovery of 85% at PH 7 and PH* with the other acid. The two reagents give sharp colour with both iron (III) and chromium (VI), so trials were carried out to compare the curves obtained with that of the original reagent i.e. Thiocynate and diphenylcarbazide, which give a smaller slope.(Author)

  2. Selective and sensitive speciation analysis of Cr(VI) and Cr(III), at sub-μgL-1 levels in water samples by electrothermal atomic absorption spectrometry after electromembrane extraction.

    Science.gov (United States)

    Tahmasebi, Zeinab; Davarani, Saied Saeed Hosseiny

    2016-12-01

    In this work, electromembrane extraction in combination with electrothermal atomic absorption spectrometry (ET-AAS) was investigated for speciation, preconcentration and quantification of Cr(VI) and Cr(III) in water samples through the selective complexation of Cr(VI) with 1,5-diphenylcarbazide (DPC) as a complexing agent. DPC reduces Cr(VI) to Cr(III) ions and then Cr(III) species are extracted based on electrokinetic migration of their cationic complex (Cr(III)-DPC) toward the negative electrode placed in the hollow fiber. Also, once oxidized to Cr(VI), Cr(III) ions in initial sample were determined by this procedure. The influence of extraction parameters such as pH, type of organic solvent, chelating agent concentration, stirring rate, extraction time and applied voltage were evaluated following a one-at-a-time optimization approach. Under optimized conditions, the extracted analyte was quantified by ETAAS, with an acceptable linearity in the range of 0.05-5ngmL -1 (R 2 value=0.996), and a repeatability (%RSD) between 3.7% and 12.2% (n=4) for 5.0 and 1.0ngmL -1 of Cr(VI), respectively. Also, we obtained an enrichment factor of 110 that corresponded to the recovery of 66%. The detection limit (S/N ratio of 3:1) was 0.02ngmL -1 . Finally, this new method was successfully employed to determine Cr(III) and Cr(VI) species in real water samples. Copyright © 2016. Published by Elsevier B.V.

  3. Selective sampling and measurement of Cr (VI) in water with polyquaternary ammonium salt as a binding agent in diffusive gradients in thin-films technique

    International Nuclear Information System (INIS)

    Chen, Hong; Zhang, Yang-Yang; Zhong, Ke-Li; Guo, Lian-Wen; Gu, Jia-Li; Bo, Le; Zhang, Meng-Han; Li, Jian-Rong

    2014-01-01

    Graphical abstract: - Highlights: • We develop a new DGT device for in situ sampling Cr (VI) in water. • Polyquaternary ammonium salt (PQAS) was used as binding agent of DGT device. • Cr (VI) can be accumulated in the PQAS binding phase whereas Cr (III) cannot. • The DGT performance was independent of pH 3–12 and ionic strength 1 × 10 −3 –1 mol L −1 . - Abstract: A diffusive gradients in thin films (DGT) device with polyquaternary ammonium salt (PQAS) as a novel binding agent (PQAS DGT) combined with graphite furnace atomic absorption spectrometry (GFAAS) was developed for the selective sampling and measurement of Cr (VI) in water. The performance of PQAS DGT was independent of pH 3–12 and ionic strength from 1 × 10 −3 to 1 mol L −1 . DGT validation experiments showed that Cr (VI) was measured accurately as well as selectively by PQAS DGT, whereas Cr (III) was not determined quantitatively. Compared with diphenylcarbazide spectrophotometric method (DPC), the measurement of Cr (VI) with PQAS DGT was agreement with that of DPC method in the industrial wastewater. PQAS-DGT device had been successfully deployed in local freshwater. The concentrations of Cr (VI) determined by PQAS DGT coupled with GFAAS in Nuer River, Ling River and North Lake were 0.73 ± 0.09 μg L −1 , 0.50 ± 0.07 μg L −1 and 0.61 ± 0.07 μg L −1 , respectively. The results indicate that PQAS DGT device can be used for the selective sampling and measurement Cr (VI) in water and its detection limit is lower than that of DPC method

  4. Reduction of hexavalent chromium by the thermophilic methanogen Methanothermobacter thermautotrophicus

    Science.gov (United States)

    Singh, Rajesh; Dong, Hailiang; Liu, Deng; Zhao, Linduo; Marts, Amy R.; Farquhar, Erik; Tierney, David L.; Almquist, Catherine B.; Briggs, Brandon R.

    2015-01-01

    Despite significant progress on iron reduction by thermophilic microorganisms, studies on their ability to reduce toxic metals are still limited, despite their common co-existence in high temperature environments (up to 70 °C). In this study, Methanothermobacter thermautotrophicus, an obligate thermophilic methanogen, was used to reduce hexavalent chromium. Experiments were conducted in a growth medium with H2/CO2 as substrate with various Cr6+ concentrations (0.2, 0.4, 1, 3, and 5 mM) in the form of potassium dichromate (K2Cr2O7). Time-course measurements of aqueous Cr6+ concentrations using 1,5-diphenylcarbazide colorimetric method showed complete reduction of the 0.2 and 0.4 mM Cr6+ solutions by this methanogen. However, much lower reduction extents of 43.6%, 13.0%, and 3.7% were observed at higher Cr6+ concentrations of 1, 3 and 5 mM, respectively. These lower extents of bioreduction suggest a toxic effect of aqueous Cr6+ to cells at this concentration range. At these higher Cr6+ concentrations, methanogenesis was inhibited and cell growth was impaired as evidenced by decreased total cellular protein production and live/dead cell ratio. Likewise, Cr6+ bioreduction rates decreased with increased initial concentrations of Cr6+ from 13.3 to 1.9 μM h-1. X-ray absorption near-edge structure (XANES) spectroscopy revealed a progressive reduction of soluble Cr6+ to insoluble Cr3+ precipitates, which was confirmed as amorphous chromium hydroxide by selected area electron diffraction pattern. However, a small fraction of reduced Cr occurred as aqueous Cr3+. Scanning and transmission electron microscope observations of M. thermautotrophicus cells after Cr6+ exposure suggest both extra- and intracellular chromium reduction mechanisms. Results of this study demonstrate the ability of M. thermautotrophicus cells to reduce toxic Cr6+ to less toxic Cr3+ and its potential application in metal bioremediation, especially at high temperature subsurface radioactive waste disposal

  5. Preparation of N-1 -naphthyl benzo- and N-phenyl benzo hydroxamic acids and study of their extractability towards Fe (III), Cr (VI) and U (VI)

    Energy Technology Data Exchange (ETDEWEB)

    Mohamed, Eltoum Elnour [Department of Chemistry, Faculty of Science, University of Khartoum, Khartoum (Sudan)

    1997-12-01

    Two aryl hydroxamic acids were prepared; The N-phenyl benzo hydroxamic acid and the N-1- naphthyl benzohydroxamic acid the first one was prepared by the partial reduction of nitrobenzene to the {beta}-phenyl hydroxylamine and coupling the latter with benzyl chloride. The reduction was carried out using ammonium chloride and zinc dust; this pair failed after so many attempts to give the N-1- naphthyl hydroxylamine. So the latter was prepared by using a somewhat milder reducing agent; hydrogen sulphide and ammonia gas in absolute alcohol. The two acids were obtained using the modified procedure of Tandon coupling the hydroxylamine with benzoyl chloride. The two acids were characterized by their melting points, elemental analysis, their I.R functional group frequencies and by their characteristic colour tests with vanadium (VI) and Iron (III). The acids were used for the extraction and spectrophotometric determination for iron (III), Chromium (VI), and Uranium (VI) from different molar solution, PH and from synthetic sea water. The maximum recovery of iron (III) occurred at PH 4 and PH 5 giving 92.25 and 91.25% when using N-1-naphthyl benzo hydroxamic acid and a maximum recovery of 100% at PH 5 with other acid. The maximum recovery of Chromium (VI) occurred at 3MH{sup 2}SO{sup 4} of 97.50% when using N-1-naphthyl benzohydroxamic acid and a maximum of 94.25% at the same molar concentration with N-phenyl benzo hydroxamic acid. The maximum recovery for Uranium (VI) was occurred at PH 7 giving 100% when using N-1-naphthyl benzo hydroxamic acid and a maximum recovery of 85% at PH 7 and PH* with the other acid. The two reagents give sharp colour with both iron (III) and chromium (VI), so trials were carried out to compare the curves obtained with that of the original reagent i.e. Thiocynate and diphenylcarbazide, which give a smaller slope.(Author) 121 refs. , 15 tabs. , 13 figs

  6. Reduction of hexavalent chromium by fasted and fed human gastric fluid. I. Chemical reduction and mitigation of mutagenicity

    Energy Technology Data Exchange (ETDEWEB)

    De Flora, Silvio, E-mail: sdf@unige.it [Department of Health Sciences, University of Genoa, 16132 Genoa (Italy); Camoirano, Anna, E-mail: Anna.Fiorenza.Camoirano@unige.it [Department of Health Sciences, University of Genoa, 16132 Genoa (Italy); Micale, Rosanna T., E-mail: rosannamicale@yahoo.it [Department of Health Sciences, University of Genoa, 16132 Genoa (Italy); La Maestra, Sebastiano, E-mail: lamaestra78@yahoo.it [Department of Health Sciences, University of Genoa, 16132 Genoa (Italy); Savarino, Vincenzo, E-mail: vsavarin@unige.it [Gastroenterology Unit, Department of Internal Medicine, University of Genoa, 16132 Genoa (Italy); Zentilin, Patrizia, E-mail: Patrizia.Zentilin@unige.it [Gastroenterology Unit, Department of Internal Medicine, University of Genoa, 16132 Genoa (Italy); Marabotto, Elisa, E-mail: emarabotto@libero.it [Gastroenterology Unit, Department of Internal Medicine, University of Genoa, 16132 Genoa (Italy); Suh, Mina, E-mail: msuh@toxstrategies.com [ToxStrategies, Mission Viejo, CA 92692 (United States); Proctor, Deborah M., E-mail: dproctor@toxstrategies.com [ToxStrategies, Mission Viejo, CA 92692 (United States)

    2016-09-01

    Evaluation of the reducing capacity of human gastric fluid from healthy individuals, under fasted and fed conditions, is critical for assessing the cancer hazard posed by ingested hexavalent chromium [Cr(VI)] and for developing quantitative physiologically-based pharmacokinetic models used in risk assessment. In the present study, the patterns of Cr(VI) reduction were evaluated in 16 paired pre- and post-meal gastric fluid samples collected from 8 healthy volunteers. Human gastric fluid was effective both in reducing Cr(VI), as measured by using the s-diphenylcarbazide colorimetric method, and in attenuating mutagenicity in the Ames test. The mean (± SE) Cr(VI)-reducing ability of post-meal samples (20.4 ± 2.6 μg Cr(VI)/mL gastric fluid) was significantly higher than that of pre-meal samples (10.2 ± 2.3 μg Cr(VI)/mL gastric fluid). When using the mutagenicity assay, the decrease of mutagenicity produced by pre-meal and post-meal samples corresponded to reduction of 13.3 ± 1.9 and 25.6 ± 2.8 μg Cr(VI)/mL gastric fluid, respectively. These data are comparable to parallel results conducted by using speciated isotope dilution mass spectrometry. Cr(VI) reduction was rapid, with > 70% of total reduction occurring within 1 min and 98% of reduction is achieved within 30 min with post-meal gastric fluid at pH 2.0. pH dependence was observed with decreasing Cr(VI) reducing capacity at higher pH. Attenuation of the mutagenic response is consistent with the lack of DNA damage observed in the gastrointestinal tract of rodents following administration of ≤ 180 ppm Cr(VI) for up to 90 days in drinking water. Quantifying Cr(VI) reduction kinetics in the human gastrointestinal tract is necessary for assessing the potential hazards posed by Cr(VI) in drinking water. - Highlights: • Cr(VI) reduction capacity was greater in post-meal than paired pre-meal samples. • Cr(VI) reduction was rapid, pH dependent, and due to heat stable components. • Gastric fluid attenuates

  7. Redução de cromo hexavalente por bactérias isoladas de solos contaminados com cromo Reduction of hexavlent chromium by isolated bacteria of contaminated soils with chromium

    Directory of Open Access Journals (Sweden)

    Daniele Conceição

    2007-12-01

    Full Text Available A redução do Cr(VI para Cr(III diminui a toxidade deste metal no ambiente, uma vez que o Cr(III é insolúvel às membranas biológicas. Assim, a redução microbiana do Cr(VI é uma alternativa para reduzir os impactos ambientais causados por este metal, utilizado em diversos processos industriais. O objetivo deste trabalho foi selecionar microrganismos a partir de solo contaminado com cromo e caracterizar sua capacidade de redução do Cr(VI durante o crescimento celular. A atividade de redução do Cr(VI pelos isolados foi quantificada com o reagente de s-difenilcarbazida. No isolamento, foram obtidas 20 bactérias resistentes a cromo(VI; seis destas foram capazes de reduzir acima de 100mg L-1 Cr(VI em 24 horas. As bactérias selecionadas foram eficientes na redução do Cr(VI e apresentam potencial para outros estudos, visando à aplicação em processos de biorremediação.The reduction of Cr(VI to Cr(III decrease the toxic effect of this metal in the environment, because Cr(III is insoluble to the biological membranes. The microbial reduction of Cr(VI it is an alternative to reduce the environmental impacts caused by this metal used in several industrial processes. The objective of this research was to select microorganisms from chromium contaminated soil and to characterize their ability to reduce Cr(VI. The activity of reduction of Cr(VI for the isolated was quantified with s-diphenylcarbazide. A group of 20 chromium resistant bacteria were isolated; six of these were able to reduce 100mg L-1 Cr(VI in 24 hours. The isolated bacteria, from contaminated soil can remediate chromate and presented potential for other studies seeking their application in bioremediation processes.

  8. Study of cis- and trans-uranium elements by paper chromatography and electrophoresis; Contribution a l'etude des elements cis- et trans-uraniens par chromatographie sur papier et electrophorese

    Energy Technology Data Exchange (ETDEWEB)

    Clanet, F [Commissariat a l' Energie Atomique, 92 - Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1968-01-01

    In this work, the field of application of paper chromatography and electrophoresis in inorganic chemistry has been extended to elements 90 to 96 in hydrochloric and nitric acid solution. Results obtained concern the following points: 1) - Characterization of the valency states of Np and of Pu using coloured reactions on chromatograms and electrophoregrams. The valency IV is characterized by alizarin, arsenazo-I and thorin-I, whilst diphenylcarbazide is used for the hexavalent state. 2) - Paper chromatography: by using as eluent, mixtures of equal parts of aqueous HCl and HNO{sub 3} solutions and of alcohols (methanol, ethanol and n-butanol), the R{sub f} values of elements 90 to 96 have been determined. It has been possible to deduce certain conclusions concerning the complexing of these elements by Cl{sup -} and NO{sub 3}{sup -} ions. 3) - We have developed an electrophoretic technique on cellulose acetate membranes in order to separate the charged species formed by the elements 90 to 96 in HCl and HNO{sub 3} solutions from 1 to 12 M. Mobility curves have been obtained. It appears from our results that the tendency for the elements considered to form anionic complexes follows the order of the ionic potentials when the valency state is four; this order is reversed for the valency three. The ions Cl{sup -} have a smaller tendency to form complexes than the NO{sub 3}{sup -} ions with respect to these elements in their oxidation state III or IV, but the reverse phenomenon is observed for U{sup VI} and Pu{sup VI}. Finally, the complexing of the cations Pu{sup 4+} and PuUO{sub 2}{sup 2+} by NO{sub 3}{sup -} follows the order of the ionic potentials but occurs in the reverse order for Cl{sup -} ions. 4) - Various analytical applications are considered: separation of the various elements from each other and separation of the valency states of Np and of Pu. (author) [French] Dans cette etude, le champ d'application de la chromatographie sur papier et de l

  9. Study of cis- and trans-uranium elements by paper chromatography and electrophoresis; Contribution a l'etude des elements cis- et trans-uraniens par chromatographie sur papier et electrophorese

    Energy Technology Data Exchange (ETDEWEB)

    Clanet, F. [Commissariat a l' Energie Atomique, 92 - Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1968-01-01

    In this work, the field of application of paper chromatography and electrophoresis in inorganic chemistry has been extended to elements 90 to 96 in hydrochloric and nitric acid solution. Results obtained concern the following points: 1) - Characterization of the valency states of Np and of Pu using coloured reactions on chromatograms and electrophoregrams. The valency IV is characterized by alizarin, arsenazo-I and thorin-I, whilst diphenylcarbazide is used for the hexavalent state. 2) - Paper chromatography: by using as eluent, mixtures of equal parts of aqueous HCl and HNO{sub 3} solutions and of alcohols (methanol, ethanol and n-butanol), the R{sub f} values of elements 90 to 96 have been determined. It has been possible to deduce certain conclusions concerning the complexing of these elements by Cl{sup -} and NO{sub 3}{sup -} ions. 3) - We have developed an electrophoretic technique on cellulose acetate membranes in order to separate the charged species formed by the elements 90 to 96 in HCl and HNO{sub 3} solutions from 1 to 12 M. Mobility curves have been obtained. It appears from our results that the tendency for the elements considered to form anionic complexes follows the order of the ionic potentials when the valency state is four; this order is reversed for the valency three. The ions Cl{sup -} have a smaller tendency to form complexes than the NO{sub 3}{sup -} ions with respect to these elements in their oxidation state III or IV, but the reverse phenomenon is observed for U{sup VI} and Pu{sup VI}. Finally, the complexing of the cations Pu{sup 4+} and PuUO{sub 2}{sup 2+} by NO{sub 3}{sup -} follows the order of the ionic potentials but occurs in the reverse order for Cl{sup -} ions. 4) - Various analytical applications are considered: separation of the various elements from each other and separation of the valency states of Np and of Pu. (author) [French] Dans cette etude, le champ d'application de la chromatographie sur papier et de l

  10. Analytical recovery of Cr (VI), Mo (VI), Ti (IV) and Co (II) by N-phenyl-meta-nitro-benzohydroxamic and N-P-tolyl-meta-nitro-benzohydroxamic acids

    International Nuclear Information System (INIS)

    Ahmed, Abdul Aziz Malik Mohamed

    2000-05-01

    , of 82.20% for Mo (VI) at pH 1.0, and of 78.47% for Co (II) at pH 8.0, whereas N-p-tolyl-m-nitro-benzohydroxamic acid was found to have a maximum extraction of 42.25% for Ti (IV) at pH 2.0, of 97.06 for Cr (VI) at 3MH 2 SO 4 , of 81.32% for Mo (VI) at pH 1.0, and of 71.13% for Co (II)) at pH 8.0. The two reagents developed yellow colour chelate with Cr(VI) which was found to have molar absorptivity equal to 9014 L.mole -1 .cm -1 at wave length 480 nm, whereas the chelate of Cr(VI) with 1,5 diphenyl-carbazide have molar absorptivity equal to 8694 L.mole -1 .cm -1 at the same wavelength. The two reagents developed colorless chelate with Ti(IV), Mo(VI) and Co(II). (Author)

  11. Accumulation and hyperaccumulation of copper in plants

    Science.gov (United States)

    Adam, V.; Trnkova, L.; Huska, D.; Babula, P.; Kizek, R.

    2009-04-01

    have adapted on such stress. The aim of this study is to investigate the behaviour of copper in plants and to assess its potential effect on the surrounding environment. To detect copper in biological samples electrochemical methods were employed particularly differential pulse voltammetry (DPV). Copper gave signals at 0.02 V measured by DPV. The obtained calibration dependence was linear (R2 = 0.995). Further, this method was utilized for determination of copper in real soil samples obtained from previously mentioned heavy-metal-polluted mining area. The content varied within range from tens to hundreds of mg of copper per kg of the soil. Moreover, we focused on investigation of copper influence on seedlings of Norway spruce. The seedlings were treated with copper (0, 0.1, 10 and 100 mM) for four weeks. We observed anatomical-morphological changes and other biochemical parameters in plants. We determined that seedlings synthesized more than 48 % protective thiols (glutathione and phytochelatins) compared to control ones. We investigated copper distribution in plant tissues by diphenylcarbazide staining. We found out that copper is highly accumulated in parenchymal stalk cells. In needles, change in auto-fluorescence of parenchymal cells of mesoderm similarly to endodermis cells. Besides, we analyzed samples of plants from the polluted area (spruce, pin, birch). The data obtained well correlated with previously mentioned. Acknowledgement The work on this experiment was supported by grant: INCHEMBIOL MSM0021622412.