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Made available in DSpace on 2018-12-11T16:50:46Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-08-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) This paper presents a slurry sampling method for total mercury determination by graphite furnace atomic absorption spectrometry (GFAAS) in tissue of fish from the Amazon. The tissue samples were lyophilized and macerated, and then the slurry samples were prepared by putting 20 mg of tissue, added to a solution containing Triton X-100, Suprapur HNO3, and zirconium nitrate directly in sampling vials of a spectrometer. Mercury standard solutions were prepared under the same conditions as the slurry samples. The slurry samples and the mercury standard solutions were sonicated for 20 s. Twenty microliters of slurry samples were injected into the graphite tube, which contained an internal wall lined with tungsten carbide. Under these conditions, it was possible to thermally stabilize the mercury up to an atomization temperature of 1700 °C. The method was validated by mercury determination in reference materials DORM-4 and DOLT-4. The LOD and LOQ were 0.014 and 0.045 mg kg−1, respectively, and recovery percentages in relation to the concentration values were certified in the order of 98%. School of Veterinary Medicine and Animal Science São Paulo State University (UNESP) Institute of Biosciences São Paulo State University (UNESP) Biochemistry Department University of Nebraska School of Veterinary Medicine and Animal Science São Paulo State University (UNESP) Institute of Biosciences São Paulo State University (UNESP) FAPESP: 2010/51332-5 FAPESP: 2013/21297-1

This study used metalloproteomic techniques to characterize mercury (Hg)-bound proteins in the muscle and liver tissue of Tucunare (Cichla spp.) collected at the Jirau Hydroelectric Power Plant in Madeira River Basin, Brazil. The proteome of the muscle and liver tissue was obtained after two steps of fractional precipitation and separating the proteins by 2-D polyacrylamide gel electrophoresis. Hg was identified and quantified in the protein spots by graphite furnace atomic absorption spectrometry after acid mineralization in an ultrasound bath. Hg with a molecular weight

Made available in DSpace on 2018-12-11T16:48:54Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-05-01 This study presents data on the extraction and characterization of proteins associated with mercury in the muscle and liver tissues of jaraqui (Semaprochilodus spp.) from the Madeira River in the Brazilian Amazon. Protein fractionation was carried out by two-dimensional electrophoresis (2D-PAGE). Mercury determination in tissues, pellets, and protein spots was performed by graphite furnace atomic absorption spectrometry (GFAAS). Proteins in the spots that showed mercury were characterized by electrospray ionization tandem mass spectrometry (ESI-MS/MS). The highest mercury concentrations were found in liver tissues and pellets (426 ± 6 and 277 ± 4 μg kg−1), followed by muscle tissues and pellets (132 ± 4 and 86 ± 1 μg kg−1, respectively). Mercury quantification in the protein spots allowed us to propose stoichiometric ratios in the range of 1–4 mercury atoms per molecule of protein in the protein spots. The proteins characterized in the analysis by ESI-MS/MS were keratin, type II cytoskeletal 8, parvalbumin beta, parvalbumin-2, ubiquitin-40S ribosomal S27a, 39S ribosomal protein L36 mitochondrial, hemoglobin subunit beta, and hemoglobin subunit beta-A/B. The results suggest that proteins such as ubiquitin-40S ribosomal protein S27a, which have specific domains, possibly zinc finger, can be used as biomarkers of mercury, whereas mercury and zinc present characteristics of soft acids. Institute of Bioscience of Botucatu São Paulo State University (UNESP), Rubião Júnior Pontifical Catholic University of Goiás (PUC) Bauru Dental School University of São Paulo-USP Institute of Bioscience of Botucatu São Paulo State University (UNESP), Rubião Júnior

Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-27T11:29:47Z No. of bitstreams: 0 Made available in DSpace on 2014-05-27T11:29:47Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-06-27 In the present study, a simple, rapid and sensitive method was developed for the determination of mercury concentrations in the muscle tissue of fish from the Brazilian Amazon using graphite furnace atomic absorption spectrometry (GFAAS) following acid mineralization of the samples in an ultrasonic cold water bath. Using copper nitrate as a chemical modifier in solution and sodium tungstate as permanent modifier, we were able to attain thermal stabilization of the mercury up to the atomisation temperature of 1600 °C in the GFAAS assay. The calculated limits of detection (LOD) and quantification (LOQ) were 0.014 and 0.047 mg kg-1, respectively. © 2013 Elsevier Ltd. All rights reserved. UNESP - São Paulo State University Biosciences Institute, Botucatu, SP UNESP - São Paulo State University Faculty of Veterinary Medicine and Animal Science, Botucatu, SP University of Alagoas - IQB/UFAL, Maceió, Al University of Brasília Faculdade de Planaltina Distrito Federal National Institute of Bioanalytical Sciences and Technology UNICAMP - Campinas State University, Campinas, SP UNESP - São Paulo State University Biosciences Institute, Botucatu, SP UNESP - São Paulo State University Faculty of Veterinary Medicine and Animal Science, Botucatu, SP

This paper presents the results obtained from selenium fractionation in plasma, muscle and liver samples of Nile tilapia’s (Oreochromis niloticus) after protein separation. The plasma, muscle and liver proteome was obtained by 2D-PAGE, and selenium in protein spots was qualitatively and quantitatively determined by synchrotron radiation X-ray fluorescence and graphite furnace atomic absorption spectrometry (GFAAS). The fluorescence spectra indicated the presence of selenium in three protein spots of plasma, two of muscle and one of liver. Selenium was found to be distributed mainly in proteins with a molar mass smaller than 57.0 kDa and with pI in the range of 5.9–9.6, with one exception in the plasma sample, which presented protein with a molar mass of 60.0 kDa. After acid mineralization of the protein spots, a GFAAS determination of the concentration of selenium bound to these proteins indicated a range of 1.35–6.82 mg per g of protein.

Made available in DSpace on 2018-12-11T17:00:50Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-03-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) The aim of this paper was to determine the zinc concentrations in muscle samples of Nile tilapia (Oreochromis niloticus) produced in aquaculture and fed diets containing inorganic and organic zinc sources. In the sample preparation step, the samples were lyophilized and ground cryogenically to produce particles smaller than 60 µm. The zinc extraction was conducted by acid mineralization using concentrated nitric acid and hydrogen peroxide in a thermostatically controlled ultrasonic batch reactor. The zinc determinations were performed by Graphite Furnace Atomic Absorption Spectrometry at a drying temperature of 90–250 °C, pyrolysis temperature of 1400 °C, atomization temperature of 2400 °C, and cleaning temperature of 2800 °C. Niobium nitrate was used as a chemical modifier co-injected with the samples, and tungsten was employed as a permanent modifier. Among the muscle tissue samples of Nile tilapia that were analyzed, zinc concentrations were determined in the range of 3.70–19.00 mg kg−1 (LOD 0.012 µg L−1 and LOQ 0.041 µg L−1). The accuracy and precision of the proposed method of zinc determination was validated using the DORM-certified standard Fish Protein 4 NRC. College of Veterinary and Animal Science São Paulo State University Department of Chemistry and Biochemistry Bioscience Institute São Paulo State University (UNESP), Rubião Júnior Federal University of Alagoas - Institute of Chemistry and Biotechnology College of Veterinary and Animal Science São Paulo State University Department of Chemistry and Biochemistry Bioscience Institute São Paulo State University (UNESP), Rubião Júnior FAPESP: 2010/51332-5 FAPESP: 2010/51562-0

This paper presents preliminary findings for a metallomics study of mercury in the muscle of the fish species from Amazonas, Brazil, after protein separation by two-dimensional polyacrylamide gel electrophoresis and subsequent evaluation of mercury by synchrotron radiation X-ray fluorescence. The fluorescence spectra revealed mercury in two protein spots. The mercury-containing protein spots showed molecular weights of 20.8 ± 0.7 and 19.8 ± 0.5 kDa and isoelectric points of 5.6 ± 0.2 and 7.5 ± 0.3, respectively.

This paper proposes a method for the determination of copper, manganese, and selenium in vegetables of conventional and organic farming in the state of Sao Paulo/Brazil using ultrasonic extraction of analytes and subsequent quantification by graphite furnace atomic absorption spectrometry (GFAAS). Using 0.10 mol L−1 of hydrochloric acid as the extracting solution, the following optimal extraction conditions were established: sample mass of 100 mg, sample grain size of

This paper presents a simple, fast and sensitive method to determine selenium in vegetable samples by graphite furnace atomic absorption spectrometry through the direct introduction of slurries of the samples into the spectrometer’s graphite tube. The limits of detection and quantification calculated for 20 readings of the blank of the standard slurries (5 mg mL−1 of microcrystalline cellulose) were 0.33 and 1.10 μg L−1. The proposed method was applied to determine selenium in samples of organically grown vegetables and its results proved compatible with those obtained from samples mineralized by acid digestion in a microwave oven.

This paper proposes a method to determine calcium, magnesium, manganese and zinc in fish feed samples using ultrasound in the analyte extraction process, and subsequent quantification by flame atomic absorption spectrometry (FAAS). Using 0.10 mol/L of HCl as extraction solution, the optimal conditions of extraction were established as follows: 100 mg of sample mass; sample granulometry of less than 60 μm; sonication time of three cycles of 10 s and sonication power of 102 W. The method was applied in studies of the digestibility of these nutrients in samples of fish feed used in the diet of Nile tilapia juveniles. The results achieved were congruent with those obtained from the mineralization of fish feed samples in the metal nutrient extraction process.

The present work develops and optimizes a method to determine copper in samples of feces and fish feed by graphite furnace atomic absorption spectrometry (GFAAS) through the direct introduction of slurries of the samples into the spectrometer’s graphite tube coated internally with metallic rhodium and tungsten carbide that acts as chemical modifiers. The limits of detection (LOD) and quantification (LOQ) calculated for 20 readings of the blank of the standard slurries (0.50% m/v of feces or feed devoid of copper) were 0.24 and 0.79 μg L−1 for the standard feces slurries and 0.26 and 0.87 μg L−1 for the standard feed slurries. The proposed method was applied in studies of absorption of copper in different fish feeds and their results proved compatible with that obtained from samples mineralized by acid digestion using microwave oven.

This work describes the synthesis and characterization of 2-aminothiazole modified silica gel (SiAT) and the studies of adsorption and pre-concentration (in batch and using a flow-injection system coupled with optical emission spectrometer) of Cd(II), Cu(II) and Ni(II) in aqueous medium. The adsorption capacity for each metal ions in mmol g−1 was: Cu(II) = 1.18, Ni(II) = 1.15 and Cd(II) = 1.10. The results obtained in the flow experiments showed about 100% of recovering of the metal ions adsorbed in a mini-column packed with 100 mg of SiAT, using 100 µL of 2.0 mol L−1 HCl solution as eluent. The quantitative sorption–desorption of the metal ions made possible the application of a flow-injection system in the pre-concentration and quantification by ICP-OES of metal ions at trace level in natural water samples.

Cellulose chemically modified with p‐aminobenzoic groups, abbreviated as Cel‐PAB, was used for preconcentration of copper, iron, nickel, and zinc from ethanol fuel, normally used in Brazil as engine fuel. The surface characteristics and the surface area of the cellulose were obtained before and after chemical modification using FT‐IR, elemental analysis, and surface area analysis (B.E.T.). The retention and recovery of the analyte elements were studied by applying batch and column techniques.

Made available in DSpace on 2015-10-21T13:11:57Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-02-01. Added 1 bitstream(s) on 2015-10-22T09:52:13Z : No. of bitstreams: 1 S0103-50532015000200239.pdf: 519548 bytes, checksum: bd9cc7af88b59229a1869b3e0cfb4781 (MD5) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) This study evaluated the metalloproteomic profile of muscle tissue samples from Nile tilapia (Oreochromis niloticus). Two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) methods was used for protein fractionation and identification based on image analysis. Determination of Ca, Cu, Fe, Mn and Zn was performed in the protein spots by flame and/or graphite furnace atomic absorption spectrometry (FAAS, GFAAS), the protein spots were characterized by electrospray ionization-tandem mass spectrometry (ESI-MS/MS). FAAS and GFAAS determinations have indicated the presence of calcium in seven protein spots, iron in only one spot, manganese in six spots, and zinc in two spots. Of the seventeen protein spots where the presence of metal ions was detected, ten were characterized by ESI-MS/MS. UNESP, Coll Vet &Anim Sci, BR-18618970 Botucatu, SP, Brazil UNESP, Inst Biosci, Dept Chem &Biochem, BR-18618970 Botucatu, SP, Brazil UNESP, Dept Biol Sci, BR-18618970 Botucatu, SP, Brazil UNESP, Coll Vet &Anim Sci, BR-18618970 Botucatu, SP, Brazil UNESP, Inst Biosci, Dept Chem &Biochem, BR-18618970 Botucatu, SP, Brazil UNESP, Dept Biol Sci, BR-18618970 Botucatu, SP, Brazil FAPESP: 2011/14902-0 FAPESP: 2010/51332-5

This paper presents the results of mercury fractionation in muscle samples of dourada ( Brachyplatystoma rousseauxii ) from the JIRAU Hydroelectric Power Plant in the Madeira River Basin in the Amazon region of Brazil. The proteome of the dourada muscle was separated by two-dimensional polyacrylamide gel electrophoresis (2D PAGE). The mercury present in the protein spots was determined by graphite furnace atomic absorption spectrometry (GFAAS) after acid mineralisation in an ultrasound bath. The protein spots in which the presence of mercury was detected were characterised by electrospray ionisation tandem mass spectrometry (ESI–MS/MS) after tryptic digestion. The GFAAS determinations indicated that 65% of the mercury was linked to the protein fraction with a molar mass (Mm) of less than 90 kDa. The mercury concentrations in the seven spots in which this protein fraction was present were in the range of 11.40–35.10 μg kg −1 . Based on the mercury concentrations, it was possible to estimate that the protein spots contained approximately 1–3 mercury atoms per protein molecule. The ESI–MS/MS analysis allowed characterisation of the seven protein spots as the following proteins: protein NLRC5 (molar mass=18.10, pI=6.30); 39S ribosomal protein L36 mitochondrial (molar mass=15.40, pI=8.23); N-alpha-acetyltransferase 20 (Mm=15.95, pI=8.80); Mth938 domain-containing protein (Mm=15.01, pI=9.60); ubiquitin-40S ribosomal protein S27a (Mm=9.80, pI=7.60); parvalbumin alpha (Mm=12.40, pI=3.80) and parvalbumin beta (Mm=13.10, pI=3.45).

This paper presents a simple, fast and sensitive method to determine chromic oxide (used as a biological marker of fish feed) in samples of fish feces by GFAAS through the direct introduction of slurries of the samples into the spectrometer's graphite tube. The standard samples of feces and of fish feed containing 0.10-1.00mgkg(-1) of Cr(2)O(3) were pre-frozen for 1min in liquid nitrogen and then ground a cryogenic mill for 2min, which reduced the samples' grain size to less than 60mum. The standard slurries were prepared by mixing 20mg of standard samples of fish feed or feces with 1mL of a solution containing 0.05% (v/v) of Triton X-100 and 0.50% (v/v) of suprapure HNO(3) directly in the spectrometer's automatic sampling glass. The final concentrations of Cr(2)O(3) present in the standard slurries were 2, 4, 8, 16 and 20mugL(-1). After sonicating the mixture for 20s, 10muL of standard slurries were injected into the graphite tube, whose internal wall was lined with a metallic palladium film that acted as a permanent chemical modifier. The limits of detection (LOD) and quantification (LOQ) calculated for 20 readings of the blank of the standard slurries (2%, m/v of feces or feed devoid of minerals) were 0.81 and 2.70mugL(-1) of Cr(2)O(3) for the standard feces slurries, 0.84 and 2.83mugL(-1) of Cr(2)O(3) for the standard feed slurries. The proposed method was applied in studies of nutrient digestibility of different fish feeds and its results proved compatible with the results obtained from samples pre-mineralized by acid digestion.

Submitted by Guilherme Lemeszenski (guilherme@nead.unesp.br) on 2013-08-22T18:49:16Z No. of bitstreams: 1 S0100-46702005000300006.pdf: 335371 bytes, checksum: 911f0121001e80fbe1609de232be0a88 (MD5) Made available in DSpace on 2013-08-22T18:49:16Z (GMT). No. of bitstreams: 1 S0100-46702005000300006.pdf: 335371 bytes, checksum: 911f0121001e80fbe1609de232be0a88 (MD5) Previous issue date: 2005-09-01 Made available in DSpace on 2013-09-30T19:09:23Z (GMT). No. of bitstreams: 2 S0100-46702005000300006.pdf: 335371 bytes, checksum: 911f0121001e80fbe1609de232be0a88 (MD5) S0100-46702005000300006.pdf.txt: 22554 bytes, checksum: a7165d37477b899b3e7a6ccfe26c7e68 (MD5) Previous issue date: 2005-09-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T14:19:42Z No. of bitstreams: 2 S0100-46702005000300006.pdf: 335371 bytes, checksum: 911f0121001e80fbe1609de232be0a88 (MD5) S0100-46702005000300006.pdf.txt: 22554 bytes, checksum: a7165d37477b899b3e7a6ccfe26c7e68 (MD5) Made available in DSpace on 2014-05-20T14:19:42Z (GMT). No. of bitstreams: 2 S0100-46702005000300006.pdf: 335371 bytes, checksum: 911f0121001e80fbe1609de232be0a88 (MD5) S0100-46702005000300006.pdf.txt: 22554 bytes, checksum: a7165d37477b899b3e7a6ccfe26c7e68 (MD5) Previous issue date: 2005-09-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) O presente trabalho descreve o desenvolvimento de um método rápido e sensível para determinar traços de mercúrio em amostras de águas naturais por espectrometria de absorção atômica com geração de vapor a frio, utilizando-se um sistema de preconcentração composto por uma mini-coluna empacotada com 100 mg de sílica gel modificada com o ligante 2-aminotiazol e acoplado em linha com o sistema de geração de vapor a frio do espectrômetro de absorção atômica. As condições ótimas de preconcentração são descritas. Os íons Hg(II) preconcentrados foram eluídos diretamente da mini-coluna para o sistema de geração de vapor a frio utilizando-se 100 µL de solução 2 mol L-1 de ácido clorídrico, com uma eficiência de 95%. Os fatores de enriquecimento determinados foram 29, 38 e 46 percolando-se 3, 4 e 5 mL de solução aquosa contendo 400 ng L-1 de Hg(II). O limite de detecção calculado foi de 5 ng L-1. O procedimento de preconcentração foi aplicado na determinação de traços de mercúrio adicionados em amostras de águas de rio. This paper discusses a rapid and sensitive method developed to determine trace levels of mercury in natural water samples by cold vapor atomic absorption spectrometry using a preconcentration system composed by mini-column packed with 100 mg of 2-aminothiazol modified silica gel (SiAT) coupled on-line with the spectrometer's cold vapor generator system. The optimum preconcentration conditions are also described here. The preconcentrated Hg(II) ions were eluted directly from the column to the spectrometer's cold vapor generator system using 100 µL of 2 mol L-1 hydrochloric acid and the retention efficiency achieved exceeded 95%. The enrichment factors determined were 29, 38 and 46 using 3, 4 and 5 mL of preconcentrated aqueous solutions containing 400 ng L-1 of Hg. The detection limit calculated was 5 ng L-1. The preconcentration procedure was applied to determine trace level mercury in spiked river water samples. UNESP Departamento de Química e Bioquímica Instituto de Biociências UNESP Departamento de Química Analítica Instituto de Química UNESP Departamento de Física e Biofísica Instituto de Biociências UNESP Departamento de Química e Bioquímica Instituto de Biociências UNESP Departamento de Química Analítica Instituto de Química UNESP Departamento de Física e Biofísica Instituto de Biociências

Silica gel chemically modified with 2-aminotiazole groups (SiAT), was used for preconcentration of cupper, zinc, nickel and iron from gasoline, normally used as a engine fuel. Surface characteristics and surface area of the silica gel were obtained before and after chemical modification using FT-IR, Kjeldhal and surface area analysis (B.E.T.). The retention and recovery of the analyte elements were studied by applying batch and column techniques. The experimental parameters, such as shaking time in batch technique, flow rate and concentration of the eluent (HCl—0.25–2.00 mol l −1 ) and the amount of silica, on retention and elution, have been investigated. Detection limits of the method for cupper, iron, nickel and zinc are 0.8, 3, 2 and 0.1 μg l −1 , respectively. The sorption–desorption of the studied metal ions made possible the development of a preconcentration method for metal ions at trace level in gasoline using flame AAS for their quantification.

This work describes the synthesis and characterization of 2-aminothiazole-modified silica gel (SiAT), as well as its application for preconcentration (in batch and column technique) of Cu(II), Ni(II) and Zn(II) in ethanol medium. The adsorption capacities of SiAT determined for each metal ion were (mmol g(-1)): Cu(II)=1.20, Ni(II)=1.10 and Zn(II)=0.90. In addition, results obtained in flow experiments, showed a recovery of ca. 100% of the metal ions adsorbed in a column packed with 500 mg of SiAT. The eluent was 2.0 mol L(-1) HCl. The sorption-desorption of the studied metal ions made possible the development of a preconcentration method for metal ions at trace level in fuel ethanol using flame AAS for their quantification.

This paper proposes a method to determine selenium in samples of fish muscle and liver tissue using ultrasound assisted extraction process, and analysed by graphite furnace atomic absorption spectrometry (GFAAS). The selenium content was extracted by 0.10 M HCl at the optimal extraction conditions which were established as follows: sample mass of 100 mg; granulometry of the sample

This work describes the synthesis of p-aminobenzoic modified cellulose (Cell-PAB), and the results of a study on the sorption and pre-concentration (using batch and in flow-through column methods) of Cd(II), Cu(II), Ni(II), Pb(II) and Zn(II) in ethanol and aqueous medium. The sorption capacities for each metal ion were (in mmol.g-1); Ethanol medium: Cd(II) = 1.45, Cu(II) = 1.85, Ni(II) = 1.65, Pb(II)= 1.40 and Zn(II)= 1.50; Aqueous medium: Cd(II)= 1.30, Cu(II)= 1.80, Ni(II)= 1.50, Pb(II)= 1.20 and Zn(II)= 1.40. A recovery of almost 100% of the metal ions was obtained from ethanol as well as aqueous medium, the ions being sorbed in a column packed with 1 g of Cell-PAB, using 5 mL of 2.0 mol L-1 HCl solution as eluent. An enrichment factor of 45 (250 mL sample, 5 mL concentrate) was obtained by this preconcentration procedure. The sorption desorption procedure applied allowed the development of a preconcentration method for metal ions at trace level in fuel ethanol and natural water samples. After elution, the metal ions were determined by flame atomic absorption spectrometry.

Made available in DSpace on 2022-04-28T19:56:24Z (GMT). No. of bitstreams: 0 Previous issue date: 1999-01-01 5-amino-1,3,4-thiadiazole-2-thiol groups attached on a silica gel surface have been used for adsorption of Cd(II), CO(II), Cu(II), Fe(III), Ni(II), Pb(II) and Zn(II) from aqueous solutions. The adsorption capacities for each metal ion were (in mmol.g-1): Cd(II)= 0.35, Co(II)= 0.10, Cu(II)= 0.15, Fe(III)= 0.20, Hg(II)= 0.46, Ni(II)= 0.16, Pb(II)= 0.13 and Zn(II)= 0.15. The modified silica gel was applied in the preconcentration and quantification of trace level metal ions present in water samples (river, and bog water). Instituto de Biociências Depto. de Quimica e Bioquimica UNESP, CP 510, 18610-000, Botucatu, SP Instituto de Química UNESP, CP 355, 14800-900 Araraquara, SP Instituto de Biociências Depto. de Fisico e Biofisica UNESP, CP 510, 18610-000, Botucatu, SP Depto. de Físico-Quimica UNESP, CP 31, 15385-000 Ilha Solteira, SP Instituto de Biociências Depto. de Quimica e Bioquimica UNESP, CP 510, 18610-000, Botucatu, SP Instituto de Química UNESP, CP 355, 14800-900 Araraquara, SP Instituto de Biociências Depto. de Fisico e Biofisica UNESP, CP 510, 18610-000, Botucatu, SP Depto. de Físico-Quimica UNESP, CP 31, 15385-000 Ilha Solteira, SP

Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-27T11:22:38Z No. of bitstreams: 0Bitstream added on 2014-05-27T14:28:35Z : No. of bitstreams: 1 2-s2.0-36148996184.pdf: 170933 bytes, checksum: 5f55fd57ba770419cc9dc1da1a6e70fc (MD5) Made available in DSpace on 2014-05-27T11:22:38Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-11-21 This paper presents a simple, fast and sensitive method to determine manganese in samples of feces and fish feed by graphite furnace atomic absorption spectrometry (GFAAS) by the direct introduction of slurries into the graphite tube. The limits of detection (LOD) and quantification (LOQ) calculated for 20 readings of the blank of the standard slurries (0.50 % m/v of feces or feed devoid of manganese) were 28 and 92 μg kg-1 for the standard feces slurries and 34 and 110 μg kg-1 for the standard feed slurries. The proposed method was applied in bioavailability studies of manganese in different fish feeds and their results proved compatible with those obtained for samples mineralized by acid digestion using microwave oven. ©2007 Sociedade Brasileira de Química. Instituto de Biociências Departamento de Química e Bioquímica Universidade Estadual Paulista, CP 510, 18618-000 Botucatu-SP Faculdade de Medicina Veterinária e Zootecnia Departamento de Melhoramento e Nutrição Animal Universidade Estadual Paulista, CP 560, 18618-000 Botucatu-SP Instituto de Biociências Departamento de Física e Biofísica Universidade Estadual Paulista, CP 510, 18618-000 Botucatu-SP Instituto de Biociências Departamento de Química e Bioquímica Universidade Estadual Paulista, CP 510, 18618-000 Botucatu-SP Faculdade de Medicina Veterinária e Zootecnia Departamento de Melhoramento e Nutrição Animal Universidade Estadual Paulista, CP 560, 18618-000 Botucatu-SP Instituto de Biociências Departamento de Física e Biofísica Universidade Estadual Paulista, CP 510, 18618-000 Botucatu-SP

This paper presents a simple, fast and sensitive method to determine selenium in samples of feces and of fish feed by graphite furnace atomic absorption spectrometry (GFAAS) through the direct introduction of slurries of the samples into the spectrometer's graphite tube. The limits of detection (LOD) and quantification (LOQ) calculated for 20 readings of the blank of the standard slurries (0.50% m/v of feces or feed devoid of selenium) were 0.31 microg l(-1) and 1.03 microg l(-1), respectively, for the standard feces slurries and 0.35 microg l(-1) and 1.16 microg l(-1), respectively, for the standard feed slurries. The proposed method was applied in studies of bioavailability of selenium in different fish feeds and the results proved consistent with that obtained from samples mineralized by acid digestion using the microwave oven.

Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-27T11:21:06Z No. of bitstreams: 0Bitstream added on 2014-05-27T14:29:00Z : No. of bitstreams: 1 2-s2.0-3542992106.pdf: 107413 bytes, checksum: 6ffdf99536740b8bdb43bd1b3d496132 (MD5) Made available in DSpace on 2014-05-27T11:21:06Z (GMT). No. of bitstreams: 0 Previous issue date: 2004-07-01 A rapid and sensitive method was developed to determine trace levels of Cd2+ ions in an aqueous medium by flame atomic absorption spectrometry, using on-line preconcentration in a mini-column packed with 100 mg of 2-aminothiazol modified silica gel (SiAT). The Cd2+ ions were sorbed at pH 5.0. The preconcentrated Cd2+ ions were directly eluted from the column to the spectrometer's nebulizer-burner system using 100 μL of 2 mol L-1 hydrochloric acid. A retention efficiency of over 95% was achieved. The enrichment factor (calculated as the ratio of slopes of the calibration graphs) obtained with preconcentrations in a mini-column packed with SiAT (A = -1.3 × 10-3 + 1.8 × 10-3 [Cd2+]) and without preconcentrations (A = 4 × 10-5 + 3.5 × 10-3[Cd2+]), was 51 and the detection limit calculated was 0.38 μg L-1. The preconcentration procedure was applied to determine trace levels of Cd in river water samples. The optimum preconcentration conditions are discussed herein. Instituto de Química Departamento de Quimica Analitica UNESP, P. O. Box 355, 14800-900, Araraquara, SP Instituto de Biociência Departamento de Quimica e Bioquimica UNESP, P. O. Box 510, 18618-000, Botucatu, SP Instituto de Biociências Departamento de Fisica e Biofisica UNESP, P. O. Box 510, 18618-000, Botucatu, SP Universidade Estadual do Maranhao CESI, 65901-480, Imperatriz, MA Instituto de Química Departamento de Quimica Analitica UNESP, P. O. Box 355, 14800-900, Araraquara, SP Instituto de Biociência Departamento de Quimica e Bioquimica UNESP, P. O. Box 510, 18618-000, Botucatu, SP Instituto de Biociências Departamento de Fisica e Biofisica UNESP, P. O. Box 510, 18618-000, Botucatu, SP

This work describes the synthesis and characterization of 2-aminothiazole modified silica gel (SiAT), and the results of a study of the adsorption and pre-concentration (in batch and using a flow-injection system coupled to an absorption atomic spectrometer) of Cu(II), Ni(II) and Pb(II) in aqueous medium. The adsorption capacities for each metal ions in mmol g-1 were: Cu(II)= 1.18, Ni(II)= 1.15 and Pb(II)= 1.10. The results obtained in the flow experiments showed a recovery of practically 100% of the metal ions adsorbed in a mini-column packed with 100 mg of SiAT, using 100 µL of 2.0 mol L-1 HCl solution as eluent. The sorption-desorption of the metal ions made possible the application of a flow-injection system for the pre-concentration and quantification by FAAS of metal ions at trace level in natural water samples digested and not digest by an oxidizing UV photolysis. Este trabalho descreve a síntese e caracterização da sílica gel modificada com grupos 2-aminotiazol (SiAT), e os resultados de um estudo de adsorção e pré-concentração (em batelada e em fluxo, utilizando-se um sistema por injeção em fluxo acoplado com um espectrômetro de absorção atômica) de Cu(II), Ni(II) e Pb(II) em meio aquoso. A capacidade máxima de adsorção da SiAT determinada para os íons metálicos estudados em mmol g-1 foram: Cu(II)= 1,18, Ni(II)= 1,15 and Pb(II)= 1,10. Os resultados obtidos nos experimentos em fluxo, mostraram uma recuperação de praticamente 100% dos íons metálicos adsorvidos em uma mini-coluna empacotada com 100 mg de SiAT, utilizando-se 100 µL de HCl 2 mol L-1 como eluente. A sorção-desorção quantitativa dos íons Cu(II), Ni(II) e Pb(II), permitiu a aplicação do sistema em fluxo na pré-concentração e posterior quantificação desses íons metálicos em amostras de águas naturais digeridas e não digeridas por oxidação com radiação UV.

Submitted by Guilherme Lemeszenski (guilherme@nead.unesp.br) on 2013-08-22T18:49:15Z No. of bitstreams: 1 S0100-46702005000200006.pdf: 278497 bytes, checksum: 042ca956321d13239095abe08d108071 (MD5) Made available in DSpace on 2013-08-22T18:49:15Z (GMT). No. of bitstreams: 1 S0100-46702005000200006.pdf: 278497 bytes, checksum: 042ca956321d13239095abe08d108071 (MD5) Previous issue date: 2005-01-01 Made available in DSpace on 2013-09-30T19:09:23Z (GMT). No. of bitstreams: 2 S0100-46702005000200006.pdf: 278497 bytes, checksum: 042ca956321d13239095abe08d108071 (MD5) S0100-46702005000200006.pdf.txt: 19923 bytes, checksum: 8e2c0e4c743e60e36ffb5ae3f9d8d08f (MD5) Previous issue date: 2005-01-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T14:19:42Z No. of bitstreams: 2 S0100-46702005000200006.pdf: 278497 bytes, checksum: 042ca956321d13239095abe08d108071 (MD5) S0100-46702005000200006.pdf.txt: 19923 bytes, checksum: 8e2c0e4c743e60e36ffb5ae3f9d8d08f (MD5) Made available in DSpace on 2014-05-20T14:19:42Z (GMT). No. of bitstreams: 2 S0100-46702005000200006.pdf: 278497 bytes, checksum: 042ca956321d13239095abe08d108071 (MD5) S0100-46702005000200006.pdf.txt: 19923 bytes, checksum: 8e2c0e4c743e60e36ffb5ae3f9d8d08f (MD5) Previous issue date: 2005-01-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) A labilidade de Cd, Cr, Cu, Mn e Pb complexados por substâncias húmicas aquáticas (HSs) foi investigada por estudos de troca iônica em batelada, utilizando-se celulose modificada com grupos p-aminobenzóico (Cell-PAB). As SHs foram extraídas de amostras de água por adsorção sobre coluna empacotada com resina XAD 8. Os complexos metal-HS foram preparados misturando-se soluções contendo SHs com soluções padrões mista dos íons metálicos (Cd, Cr, Cu, Mn e Pb). Os resultados obtidos indicaram que houve um decréscimo nos valores dos coeficientes de distribuição (Kd) da Cell-PAB com a adição das SHs nas soluções dos íons metálicos, e que a labilidade das frações metálicas complexadas pelas SHs é menor em valores de pH < 4,0, tempo de complexação > 10 h e concentração de SHs > 500 mg L-1 . A troca iônica entre a Cell-PAB e os complexos metal-SHs obedecem as seguintes ordens de labilidade: Cd < Pb < Mn @ Cr < Cu. The lability of Cd(II), Cr(III), Cu(II), Mn(II) and Pb(II) complexed by humic substances (HSs) was investigated by means of ion exchange on cellulose modified with p-aminobenzoic groups (Cell-PAB), using a batch procedure. The HSs were extracted from water samples using adsorption in a column packed with XAD 8 resin. The metal-HS complexes were prepared by adding solutions containing all the aforementioned metal ions ( Cd(II), Cr(III), Cu(II), Mn(II) and Pb(II) ). The results indicated that the distribution coefficients (Kd) of Cell-PAB decreased with the presence of HSs, and that the lability of metal fractions complexed by HSs decreases in pH values > 4.0, complexation time > 10 h and HS concentration > 500 mg L-1. The metal exchange between HSs and Cell-PAB exhibited the following order of metal ion lability: Cd < Pb < Mn @ Cr < Cu. UNESP Instituto de Química Departamento de Química Analítica UNESP Intitutto de Biociências Departamento de Física e Biofísica UNESP Instituto de Biociência Departamento de Química e Bioquímica UNESP Instituto de Química Departamento de Química Analítica UNESP Intitutto de Biociências Departamento de Física e Biofísica UNESP Instituto de Biociência Departamento de Química e Bioquímica

Submitted by Guilherme Lemeszenski (guilherme@nead.unesp.br) on 2013-08-22T18:49:14Z No. of bitstreams: 1 S0100-46702004000200005.pdf: 1736006 bytes, checksum: 2a71b44c613c57ec2dc8f1638bf879a6 (MD5) Made available in DSpace on 2013-08-22T18:49:14Z (GMT). No. of bitstreams: 1 S0100-46702004000200005.pdf: 1736006 bytes, checksum: 2a71b44c613c57ec2dc8f1638bf879a6 (MD5) Previous issue date: 2004-01-01 Made available in DSpace on 2013-09-30T19:09:33Z (GMT). No. of bitstreams: 2 S0100-46702004000200005.pdf: 1736006 bytes, checksum: 2a71b44c613c57ec2dc8f1638bf879a6 (MD5) S0100-46702004000200005.pdf.txt: 23384 bytes, checksum: ef1de06140b77b738726e1d172cd0b68 (MD5) Previous issue date: 2004-01-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T14:19:50Z No. of bitstreams: 2 S0100-46702004000200005.pdf: 1736006 bytes, checksum: 2a71b44c613c57ec2dc8f1638bf879a6 (MD5) S0100-46702004000200005.pdf.txt: 23384 bytes, checksum: ef1de06140b77b738726e1d172cd0b68 (MD5) Made available in DSpace on 2014-05-20T14:19:50Z (GMT). No. of bitstreams: 2 S0100-46702004000200005.pdf: 1736006 bytes, checksum: 2a71b44c613c57ec2dc8f1638bf879a6 (MD5) S0100-46702004000200005.pdf.txt: 23384 bytes, checksum: ef1de06140b77b738726e1d172cd0b68 (MD5) Previous issue date: 2004-01-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Sílica gel quimicamente modificada com grupos 2-aminotiazol (SiAT), foi utilizada na preconcentração traços de cobre, ferro, níquel e zinco em meio não aquoso. O material organofuncionalizado foi caracterizado por determinação da área superficial, análise elementar de nitrogênio e FTIR. A capacidade de retenção e recuperação dos íons metálicos foi estudada utilizando-se o método em batelada e por coluna. Os parâmetros experimentais, como tempo de contato dinâmico na técnica em batelada, vazão e concentração do eluente, massa de adsorvente (SiAT) na técnica em coluna, foram investigados. O limite de detecção determinado para o método de pré-concentração foi de 0,77, 2,92, 1,73 e 0,097 mg L-1, respectivamente para cobre, ferro, níquel e zinco. A sorção-desorção quantitativa dos íons metálicos estudados, possibilitou a aplicação do método na préconcentração de traços de cobre, ferro, níquel e zinco em amostras de querosene combustível, para posterior quantificação por FAAS. Silica gel chemically modified with 2-Aminotiazole groups, abbreviated as SiAT, was used for preconcentration of copper, zinc, nickel and iron from kerosene, normally used as a engine fuel for airplanes. Surface characteristics and surface area of the silica gel were obtained before and after chemical modification using FT-IR, Kjeldhal and surface area analysis (B.E.T.). The retention and recovery of the analyte elements were studied by applying batch and column techniques. The experimental parameters, such as shaking time in batch technique, flow rate and concentration of the eluent (HCl- 0.25-2.00 mol L-1) and the amount of silica, on retention and elution, have been investigated. Detection limits of the method for copper, iron, nickel and zinc are 0.77, 2.92, 1.73 and 0.097 mg L-1, respectively. The sorption-desorption of the studied metal ions made possible the development of a preconcentration method for metal ions at trace level in kerosene using flame AAS for their quantification. UNESP Instituto de Química Departamento de Química Analítica USP Centro de Energia Nuclear na Agricultura UNESP Instituto de Biociências Departamento de Física e Biofísica UNESP Instituto de Biociências Departamento de Química e Bioquímica UNESP Instituto de Química Departamento de Química Analítica UNESP Instituto de Biociências Departamento de Física e Biofísica UNESP Instituto de Biociências Departamento de Química e Bioquímica