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Fast sequential multi-element determination of Ca, Mg, K, Cu, Fe, Mn and Zn for foliar diagnosis using high-resolution continuum source flame atomic absorption spectrometry: Feasibility of secondary lines, side pixel registration and least-squares background correction

de Oliveira, Silvana Ruella; Raposo, Jorge Luiz; Gomes Neto, Jose Anchieta
Fonte: Pergamon-Elsevier B.V. Ltd Publicador: Pergamon-Elsevier B.V. Ltd
Tipo: Artigo de Revista Científica Formato: 593-596
ENG
Relevância na Pesquisa
126.42%
The fast sequential multi-element determination of Ca, Mg, K, Cu, Fe, Mn and Zn in plant tissues by high-resolution continuum source flame atomic absorption spectrometry is proposed. For this, the main lines for Cu (324.754 nm), Fe (248.327 nm), Mn (279.482 nm) and Zn (213.857 nm) were selected, and the secondary lines for Ca (239.856 nm), Mg (202.582 nm) and K (404.414 nm) were evaluated. The side pixel registration approach was studied to reduce sensitivity and extend the linear working range for Mg by measuring at wings (202.576 nm; 202.577 nm; 202.578 nm; 202.580 nm: 202.585 nm; 202.586 nm: 202.587 nm; 202.588 nm) of the secondary line. The interference caused by NO bands on Zn at 213.857 nm was removed using the least-squares background correction. Using the main lines for Cu, Fe, Mn and Zn, secondary lines for Ca and K, and line wing at 202.588 nm for Mg, and 5 mL min(-1) sample flow-rate, calibration curves in the 0.1-0.5 mg L-1 Cu, 0.5-4.0 mg L-1 Fe, 0.5-4.0 mg L-1 Mn, 0.2-1.0 mg L-1 Zn, 10.0-100.0 mg L-1 Ca, 5.0-40.0 mg L-1 Mg and 50.0-250.0 mg L-1 K ranges were consistently obtained. Accuracy and precision were evaluated after analysis of five plant standard reference materials. Results were in agreement at a 95% confidence level (paired t-test) with certified values. The proposed method was applied to digests of sugar-cane leaves and results were close to those obtained by line-source flame atomic absorption spectrometry. Recoveries of Ca...

Determination of macro- and micronutrients in plant leaves by high-resolution continuum source flame atomic absorption spectrometry combining instrumental and sample preparation strategies

Oliveira, Silvana R.; Gomes Neto, Jose A.; Nobrega, Joaquim A.; Jones, Bradley T.
Fonte: Pergamon-Elsevier B.V. Ltd Publicador: Pergamon-Elsevier B.V. Ltd
Tipo: Artigo de Revista Científica Formato: 316-320
ENG
Relevância na Pesquisa
126.34%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); A method for determination of B, Ca, Cu, Fe, K, Mg, Mn, Mo, P. S and Zn in plant tissues by high-resolution continuum source flame atomic absorption spectrometry (HR-CS FAAS) is proposed. This method is based on special features of HR-CS-AAS, such as side pixel registration, wavelength integrated absorbance, and molecular absorption bands, for determining macro- and micronutrients in foliar analysis without requiring several different strategies for sample preparation and adjustment of the analytes concentration ranges. Plant samples were analyzed and results for certified materials were in agreement at a 95% confidence level (paired t-test) with reference values. Recoveries of analytes added to plant digests varied within the 82-112% interval. Relative standard deviations (n = 12) were lower than or equal to 5.7% for all analytes in all concentration ranges. (C) 2010 Elsevier B.V. All rights reserved.

DETERMINATION of SILICON IN LUBRICANT OIL BY HIGH-RESOLUTION CONTINUUM SOURCE FLAME ATOMIC ABSORPTION SPECTROMETRY USING LEAST-SQUARE BACKGROUND CORRECTION and INTERNAL STANDARDIZATION

Raposo, Jorge Luiz; Oliveira, Silvana Ruella; Gomes Neto, Jose Anchieta; Nobrega, Joaquim Araujo; Jones, Bradley Todd
Fonte: Taylor & Francis Inc Publicador: Taylor & Francis Inc
Tipo: Artigo de Revista Científica Formato: 2150-2161
ENG
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116.27%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); The least-squares background correction (LSBC) and internal standardization procedures were combined to eliminate spectral interferences caused by the CS molecular band (251.602 nm) and transport effects for determining Si in sulfuric acid digests of lubricant oil by high-resolution continuum source flame atomic absorption spectrometry. Aluminum, Ba, Ti, V, and W were tested as internal standard (IS) candidates, and W provided the best results. For absorbance measurements of solutions containing 0.5-5.0 mg L-1 Si in the presence of 25 mg L-1 W (at the wavelength integrated absorbance equivalent to 3 pixels), the correlation coefficient for the ratio of absorbance of Si to absorbance of W vs. analyte concentration was 0.9978. Fluctuations in analytical signals due to variations in sulfuric acid concentrations or acetylene/nitrous oxide flow-rate ratios were corrected by using this calibration plot. Relative standard deviations varied from 1.9 to 7.2% and 2.1 to 5.4% (n=12) with and without LSBC/IS, respectively. Recoveries for samples spiked with 2.0 mg L-1 Si in 5.0% (v/v) sulfuric acid were within the 72.5-82.5% and 94.0-99.0% ranges without correction and by LSBC associated with internal standardization procedure...

Bismuth as a general internal standard for lead in atomic absorption spectrometry

Bechlin, Marcos A.; Fortunato, Felipe M.; Ferreira, Edilene C.; Gomes Neto, Jose A.; Nobrega, Joaquim A.; Donati, George L.; Jones, Bradley T.
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 24-30
ENG
Relevância na Pesquisa
106.38%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Processo FAPESP: 12/13500-9; Processo FAPESP: 12/23323-7; Bismuth was evaluated as internal standard for Pb determination by line source flame atomic absorption spectrometry (LS FAAS), high-resolution continuum source flame atomic absorption spectrometry (HR-CS FAAS) and line source graphite furnace atomic absorption spectrometry (LS GFAAS). Analysis of samples containing different matrices indicated close relationship between Pb and Bi absorbances. Correlation coefficients of calibration curves built up by plotting A(Pb)/A(Bi) versus Pb concentration were higher than 0.9953 (FAAS) and higher than 0.9993 (GFAAS). Recoveries of Pb improved from 52-118% (without IS) to 97-109% (IS, LS FAAS); 74-231% (without IS) to 96-109% (IS, HR-CS FAAS); and 36-125% (without IS) to 96-110% (IS, LS GFAAS). The relative standard deviations (n = 12) were reduced from 0.6-9.2% (without IS) to 0.3-4.3% (IS, LS FAAS); 0.7-7.7% (without IS) to 0.1-4.0% (IS, HR-CS FAAS); and 2.1-13% (without IS) to 0.4-5.9% (IS, LS GFAAS). (C) 2014 Elsevier B.V. All rights reserved.

Direct solid sampling by flame atomic absorption spectrometry: determination of manganese in coal samples

Flores,Érico M. M.; Paniz,José Neri G.; Saidelles,Ana Paula F.; Barin,Juliano S.; Dressler,Valderi L.; Müller,Edson I.; Costa,Adilson B.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2004 EN
Relevância na Pesquisa
126.4%
A new device for the direct solid analysis by flame atomic absorption spectrometry was investigated as an alternative technique for the determination of trace elements in coal. The potential application of the proposed procedure for the determination of manganese was investigated. Ground coal test samples were weighed directly into polyethylene vials and carried as a dry aerosol to a slotted quartz vaporization cell placed between the flame burner and optical path. The transient signals obtained were totally integrated in 1 second. The effect of operating conditions on the analytical signal was investigated. Background signals were always low and a Mn characteristic mass of 1.9 ng was found. Results were considered satisfactory regarding to both accuracy (between 97.5 and 103.2%) and precision (RSD better than 6%). The proposed system is simple and can be easily adapted to any conventional atomic absorption spectrometers allowing the analysis of more than 80 test samples in an hour.

Solid sampling analysis by flame atomic absorption spectrometry for lead determination in seawater samples after pre-concentration using cocrystallized alizarin red - naphthalene

Korn,Maria das Graças Andrade; Bispo,Márcia Sousa; Korn,Mauro; Costa,Adilson Ben da; Mattos,Julio Cezar Paz de; Paniz,José Neri Gottfried; Flores,Érico Marlon de Moraes
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2005 EN
Relevância na Pesquisa
126.45%
A device for direct solid analysis by flame atomic absorption spectrometry (DSA-FAAS) with prior solid phase extraction procedure is proposed for the determination of lead in water samples. A buffer solution (NH4Cl-NH3, pH 8.1) and alizarin red - naphthalene solid phase were added for Pb sorption. After, samples (up to 200 mL) were filtered and the naphthalene matrix was dried, ground to particle size < 80 µm and then maintained into a desiccator up to the Pb determination by DSA-FAAS. Test samples (from 0.1 to 2 mg) were weighed into small polyethylene vials. Vials were connected to a homemade device for solid introduction directly into a conventional air + acetylene flame. Test samples were carried as a dry aerosol to a T-quartz cell specially designed for DSA-FAAS. The T-quartz cell was positioned above the burner and below the optical path of the instrument. In the flame, the generated atomic vapor produced a transient signal that was totally integrated in 2 s. The effect of operating conditions on the analytical signal was evaluated. Background signals were always low (wavelength=217.0 nm) and no memory effects were observed. A characteristic mass of 1.1 ng for Pb was found. Calibration was performed using different masses of solid alizarin red-naphthalene spiked with Pb reference solution. Results were considered satisfactory...

Hydride generation-in situ trapping-flame atomic absorption spectrometry hybridization for indium and thallium determination

Matusiewicz,Henryk; Krawczyk,Magdalena
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2007 EN
Relevância na Pesquisa
126.38%
The analytical performance of coupled hydride generation-integrated atom trap (HG-IAT) atomizer flame atomic absorption spectrometry (FAAS) system was evaluated for determination of In and Tl in reference material. Indium, using formation of InH3 and TlH vapors were atomized in air-acetylene flame-heated IAT. A new design of HG-IAT-FAAS hyphenated technique that would exceed the operational capabilities of existing arrangements (a water-cooled single silica tube, double-slotted quartz tube or an "integrated trap") was investigated. A dramatic improvement in detection limits was achieved compared with that obtained using either of the atom trapping techniques, presented above, separately. The detection limits, defined as 3 times the blank standard deviation (3sigma), were 0.60 and 0.40 ng mL-1 for In and Tl, respectively. For a 120 s in situ pre-concentration time (sample volume of 2 mL), sensitivity enhancement compared to flame AAS, were 417 and 450 folds for In and Tl, respectively, using hydride generation-atom trapping technique. The sensitivity can be further improved by increasing the collection time. The precision, expressed by RSD, was 4.4% and 5.2% (n = 6) for In and Tl, respectively. The designs studied included slotted tube...

Uncertainties related to linear calibration curves: a case study for flame atomic absorption spectrometry

Chui,Queenie S. H.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2007 EN
Relevância na Pesquisa
126.32%
Least squares linear regression is widely used in analytical chemistry. In practice a linear relationship between substance content and measured value still has been assumed based on the correlation coefficient criterion, although not recommended. Textbooks provide the necessary formulas for the fitting process, based on the assumption that there is no error in the independent variable. In practice the ordinary least squares (OLS) textbook procedure is used even when the previously stated assumptions are not strictly fulfilled. In this paper, how to validate the calibration function is dealt with in detail using as an example based on measurements obtained for nickel determination by flame atomic absorption spectrometry (FAAS). Assessing uncertainties related to linear calibration curves is also discussed. Considering uncertainties of weights and volumetric equipment and instrumental analytical signal it is observed that the most important factor that contributes to the final uncertainty is the uncertainty of the calibration function.

Background corrected dispersive liquid-liquid microextraction of cadmium combined with flame atomic absorption spectrometry

Karim-Nezhad,Ghasem; Ahmadi,Mohammad; Zare-Dizajdizi,Behruz
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2011 EN
Relevância na Pesquisa
126.45%
A new procedure was developed for dispersive liquid-liquid micro extraction of cadmium prior to its determination by flame atomic absorption spectrometry. The major difficulty in combination of dispersive liquid-liquid microextraction with flame atomic absorption spectrometry is high background absorption of the extraction and disperser solvents that covers the absorbance of analyte. The background absorption was removed by changing the solvent of sedimented phase from organic to aqueous. In the proposed approach, tetrachloroethylene (C2Cl4) and tetrahydroforan (THF) were used as extraction and dispersive solvents respectively. Dithizone was used as complexing agent. Several factors that may be affect on the extraction process, such as, extraction solvent, disperser solvent, the volume of extraction and disperser solvent, extraction time, temperature of solution, concentration of chelating agent and pH were optimized. The effects of common coexisting ions on the recovery of cadmium were studied. Results showed that cadmium recoveries are almost quantitative in the presence of interfering ions. Under the optimal conditions the enrichment and enhancement factors were 34.5 and 26 respectively, the extraction and relative recoveries were 69% and 99% respectively...

Speciation of Fe(II) and Fe(III) by using dispersive liquid-liquid microextraction and flame atomic absorption spectrometry

Bahar,Soleiman; Zakerian,Razieh
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/05/2012 EN
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126.32%
An extraction method for Fe(III) from water sample before spectrometric determination was developed. Dispersive liquid-liquid microextraction (DLLME) technique was successfully used as sample preparation method for flame atomic absorption spectrometry (FAAS). In the proposed approach, 8-hydroxy quinoline (oxine) was used as chelating agent, chloroform and methanol were selected as extraction and dispersive solvents, respectively. Some factors influencing the extraction efficiency of Fe(III) and its subsequent determination were studied and optimized, including: type and volume of extraction and dispersive solvents, pH of sample solution, concentration of the chelating agent and extraction time. Under the optimized conditions, the enrichment factor of this method for Fe(III) was 462. The limit of detection for Fe(III) was 4.5 ng mL-1, and the relative standard deviation (RSD) 1.4% (n = 5, c = 400 ng mL-1).

Preconcentration procedure using vortex agitator system for determination of trace levels of cadmium by flame atomic absorption spectrometry

Chamsaz,Mahmoud; Eftekhari,Mohammad; Atarodi,Atefe; Asadpour,Saeid; Ariani,Maral
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2012 EN
Relevância na Pesquisa
126.32%
A simple and rapid vortex-assisted ionic liquid based liquid-liquid microextraction (VALLME) procedure was used for the determination of trace amounts of cadmium by flame atomic absorption spectrometry (FAAS). Ionic liquid (IL), 1-hexyl-3-methylimidazolium hexafluorophosphate ([Hmim][PF]), was used as an extractant solvent. Cd2+ was complexed with ammonium pyrrolidinedithiocarbamate (APDC) and then entered into the fine IL droplets by the assistance of vortex agitator system. Some effective factors that influence the extraction efficiency such as pH, ligand concentration, amount of ionic liquid, extraction time and ionic strength effect were completely investigated and optimized. Under the optimum conditions, the limit of detection (LOD) was 1.1 ng mL-1. The relative standard deviation (RSD) was 4.3% for 20 ng mL-1 of cadmium (n = 10), and the calibration graph using the preconcentration method was linear from 5 to 150 µg L-1, with a correlation coefficient of 0.998. The proposed method was successfully applied for determination of cadmium in water samples and spinach leaves.

Trace determination of cadmium ions by flame atomic absorption spectrometry after pre-concentration using temperature-controlled ionic liquid dispersive-liquid phase microextraction

Bamdad,Farzad; Ardalani,Mehdi; Sangi,Mohammad R.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2014 EN
Relevância na Pesquisa
126.32%
This paper is about an improved temperature-controlled ionic liquid dispersive liquid-phase microextraction method for pre-concentration of cadmium ions prior to determination by flame atomic absorption spectrometry. In this study, 1-butyl-3-methylimidazolium hexafluorophosphate ([C4MIM][PF6]) was used as extraction solvent. Cadmium complexed with dithizone, and then entered into the dispersed ionic liquid droplets at 40 ºC. Some parameters affecting the extraction efficiency such as the volume of [C4MIM][PF6], dissolving temperature, sample pH, centrifuging time and salt effect have been investigated in detail. The calibration graph was linear in the range of 2-250 ng mL-1, the limit of detection (3Sb) was 0.62 ng mL-1. The enhancement factor was found to be 48.4 and the relative standard deviation (RSD) for 10 replicate determinations of 50 ng mL-1 Cd was 2.7%. The developed method successfully applied to the determination of cadmium in several real samples.

Pre-concentration of traces of cadmium, cobalt, nickel and lead in natural honeys by solid phase extraction followed by their determination using flame atomic absorption spectrometry

Stecka,Helena; Jedryczko,Dominika; Pohl,Pawel; Welna,Maja
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2014 EN
Relevância na Pesquisa
126.35%
A simple and fast sample preparation procedure for the determination of traces of Cd, Co, Ni and Pb in honeys was proposed. It included the preparation of acidified sample solutions of honeys, the retention of elements of interest on resin beds of a strongly acidic gel cation exchanger Dowex 50W×8-400, and their elution with a 3.0 mol L-1 HCl solution prior to measurements by flame atomic absorption spectrometry (FAAS). The method provided the precision and the accuracy better than 4.5% and detection limits of 0.005 µg g-1 (Cd), 0.015 µg g-1 (Co, Ni) and 0.073 µg g-1 (Pb). The reliability of results obtained with the developed procedure and FAAS was validated by the recovery test and the comparison with results achieved using the wet digestion and inductively coupled plasma optical emission spectrometry. The method was applied for the analysis of sixty nine samples of honeys originated from the Lower Silesia region (southeast Poland). It was found that Cd, Co and Pb were under detection limits, while Ni was determined in nine honeys at the level of 0.19-0.93 µg g-1.

Preconcentration and determination of cadmium in water and food samples by in situ surfactant-based solid-phase extraction and flame atomic absorption spectrometry

Jamali,Mohammad Reza; Boromandi,Afsaneh
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2014 EN
Relevância na Pesquisa
126.32%
In situ surfactant-based solid-phase extraction (ISS-SPE) is proposed as a preconcentration procedure for the determination of cadmium in water and food samples by flame atomic absorption spectrometry. In the present work, cetyltrimethylammonium bromide was used as a cationic surfactant, hexafluorophosphate ion as an ion-pairing agent and 4-benzylpiperidinedithiocarbamate potassium salt (K-4-BPDC) as a chelating agent. Several variables that affect the extraction efficiencies such as pH, type and amount of surfactant, concentration of ion-pairing agent, concentration of chelating agent, ionic strength and extraction time were investigated and optimized. After optimization of the complexation and extraction conditions, an enrichment factor of 40 was obtained. The calibration curve was linear in the range of 1-50 µg L-1 and the limit of detection was 0.3 µg L-1. The relative standard deviation for 20 µg L-1 of cadmium was lower than 2.2%. Validation of the methodology was performed by standard addition method and analysis of certified reference materials. The method was successfully applied to the determination of cadmium in various food and water samples.

Determination of Metal Loading in Heterogeneous Catalyst by Slurry Sampling Flame Atomic Absorption Spectrometry

Garcia,Marco A. S.; Silvestre,Daniel M.; Nomura,Cassiana S.; Rossi,Liane M.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2015 EN
Relevância na Pesquisa
126.32%
Quantification of metal loading in supported catalysts is imperative; however, the analytical methods are usually time-consuming, expensive, and require sophisticated equipment and sample extraction with hazardous and corrosive strong acids. Herein, we report a new method for quantification of metal in supported catalysts using slurry sampling flame atomic absorption spectrometry. The slurry sampling method was used for determination of gold and the results were similar to those obtained with the traditional extraction method using aqua regia; however, it overcomes the main drawbacks associated with sample digestion by avoiding the use of concentrated toxic reagents, minimizing sample manipulation, and consequently, reducing the risks of contamination and the sample preparation time. Ultrasound radiation optimization associated with the solvent, mass of sample, concentration, and matrix effect in the slurry analysis allowed direct analysis by using the calibration in aqueous medium. The slurry sampling procedure could be applied to other catalysts with different supports and in bimetallic systems.

Potentialities of hydride generation atomic absorption spectrometry (HGAAS) in the fast sequential determination of AS, BI and SB.

CARAPELLI, R.; GUERRA, M. B. B.; MIRANDA, K. dos A. de; PEREIRA FILHO, E. R.; NOGUEIRA, A. R. de A.
Fonte: In: RIO SYMPOSIUM ON ATOMIC SPECTROMETRY, 11., 2010, Mar del Prata: Horiba, 2010. Publicador: In: RIO SYMPOSIUM ON ATOMIC SPECTROMETRY, 11., 2010, Mar del Prata: Horiba, 2010.
Tipo: Resumo em anais de congresso (ALICE) Formato: p. 169
PT_BR
Relevância na Pesquisa
116.21%
In this study, a sensitive hydride generation method was combined with fast sequential flame atomic absorption spectrometry (FS-FAAS) for the sequential determination of As, Bi and Sb in water samples. A Doehlert design was performed to identify a compromise condition to determine sequentially the three elements. The best condition was reached using NaBH40.8 % mv-1as the reducing agent. Another four variables were also tested: HCI concentration as the carrier solution (2 to 10 mol L-1), KI concentration as the pre-reductor solution (1 to 7 % mv-1), employment of ascorbic acid (0 to 6 % mv-1) as auxiliary pre-reductor, and integration time (3 replicates of 0.5 to 2 s). All these evaluated conditions were not significant at the investigated levels. Therefore, the optimized parameters were: HCI 6 mol L-1 in order to avoid interferences from the matrix, KI 1 % mv-1 without ascorbic acid to reduce reagent consumption and waste generation, finally, because of the lower delay time (20s) of the measurements, integration time of 1 s with 5 replicates was employed to precision improvement. That delay time was chosen as the minimum time to signal stabilization after the entire signal profile examination. The linear ranges were from 0.5 to 1 0 ~g L-1 of As...

Synthesis of Nano-Pore Size Ag(I)-Imprinted Polymer for the Extraction and Preconcentration of Silver Ions Followed by Its Determination with Flame Atomic Absorption Spectrometry and Spectrophotometry Using Localized Surface Plasmon Resonance Peak of Silver Nanoparticles

Dadfarnia,Shayessteh; Shabani,Ali Mohammad Haji; Kazemi,Elahe; Ahmad,Seyed; Khormizi,Heydari; Tammadon,Fattema
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2015 EN
Relevância na Pesquisa
126.32%
Silver ion imprinted polymer (IIP) was synthesized in the presence of Ag(I)-N,N’‑bis(salicylidene)ethylenediamine (salen) complex using 4-vinylpyridine as the functional monomer, ethylene glycol dimethacrylate (EGDMA) as the crosslinker, and 2,2-azobis(isobutyronitrile) (AIBN) as the initiator. The Ag(I)-imprinted polymer (IIP) particles were characterized by SEM (scanning electron microscope), FTIR (Fourier transform infrared spectroscopy) and BET/BJH (Brunauer-Emmett-Teller/Barrett-Joyner-Halenda) analysis. The imprinted Ag(I) ions were completely removed by leaching the IIP with thiourea (0.5 mol L-1). The polymer was employed as a selective sorbent for extraction and separation of the trace amounts of the Ag(I) ions. The preconcentrated ion was determined via the flame atomic absorption spectrometry (FAAS) or it was reduced to silver nanoparticles and quantified by spectrophotometry based on its localized surface plasmon resonance peak (LSPRP). The figures of merit of both methods were compared. Under the optimized conditions, a sample volume of 80 mL resulted in an enhancement factor of 312. The detection limit (3Sb/m) and the relative standard deviation (n = 10) at 10 µg L-1 level for FAAS were found to be 0.06 µg L-1...

Solid phase extraction of zinc with octadecyl silica membrane disks modified by N,N'-disalicylidene-1,2-phenylendiamine and determination by flame atomic absorption spectrometry

Shabany,M.; Haji Shabani,A. M.; Dadfarnia,S.; Gorji,A.; Ahmadi,S. H.
Fonte: Fundação Editora da Universidade Estadual Paulista Júlio de Mesquita Filho - UNESP Publicador: Fundação Editora da Universidade Estadual Paulista Júlio de Mesquita Filho - UNESP
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2008 EN
Relevância na Pesquisa
126.39%
A procedure for separation and preconcentration of trace amounts of Zn(II) from aqueous media is proposed. The procedure is based on the adsorption of Zn2+ on octadecyl bonded silica membrane disk modified with N,N'-disalicylidene-1,2-phenylendiamine at pH 7. The retained zinc ions were then stripped from the disk with a minimal amount of 1.5 mol L-1 hydrochloric acid solution as eluent, and determined by flame atomic absorption spectrometry. Maximum capacity of the membrane disk modified with 5 mg of the ligand was found to be 226 µg Zn2+. The relative standard deviation of zinc for ten replicate extraction of 10 µg zinc from 1000 mL samples was 1.2%. The limit of detection of the proposed method was 14 ng of Zn2+ per 1000 mL. The method was successfully applied to the determination of zinc in natural water samples and accuracy was examined by recovery experiments and independent analysis by graphite furnace atomic absorption spectrometry (GFAAS).

Determination of serum lithium: comparison between atomic emission and absorption spectrometry methods

Santo,Carlos Elielton do Espírito; Carvalho,Teresa Maria de Jesus Ponte
Fonte: Sociedade Brasileira de Patologia Clínica; Sociedade Brasileira de Patologia; Sociedade Brasileira de Citopatologia Publicador: Sociedade Brasileira de Patologia Clínica; Sociedade Brasileira de Patologia; Sociedade Brasileira de Citopatologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2014 EN
Relevância na Pesquisa
106.51%
Introduction: The therapeutic monitoring of lithium, through concentration measurements, is important for individual dose adjustment, as a marker of treatment adherence and to prevent poisoning and side effects. Objectives: Validate and compare two methods - atomic emission and atomic absorption - for the determination of lithium in serum samples. Methodology: Parameters such as specificity, precision, accuracy, limit of detection (LOD) and linearity were considered. The atomic absorption spectrometer was used, operating in either emission or absorption mode. For the quantitative comparison of 30 serum samples from patients with mood disorder treated with lithium, the results were submitted to Student's t-test, F-test and Pearson's correlation. Results: The limit of quantification (LOQ) was established as 0.05 mEq/l of lithium, and calibration curves were constructed in the range of 0.05-2 mEq/l of lithium, using aqueous standards. Sample preparation time was reduced, what is important in medical laboratory. Conclusion: Both methods were considered satisfactory, precise and accurate and can be adopted for lithium quantification. In the comparison of quantitative results in lithium-treated patients through statistical tests...

Determinação indireta de N-total em plantas por espectrometria de absorção atômica com chama empregando uma mini-coluna de AgCl(s); Indirect determination of N-total in plant materials by flame atomic absorption spectrometry involving a AgCl(s) mini-column

Carneiro, Josiane Meire Tolotti; Zagatto, Elias Ayres Guidetti; Mattos, Ivanildo Luiz de; Melo, Denise
Fonte: Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz Publicador: Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; ; ; ; Formato: application/pdf
Publicado em 01/03/2001 POR
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Um sistema de análises químicas por injeção em fluxo empregando uma mini-coluna de AgCl(s) é proposto para a determinação de nitrogênio total em plantas por espectrometria de absorção atômica com chama. O método se baseia na remoção de íons Ag+ por amônia com formação do complexo diamino argentato(I) e posterior direcionamento da amostra a um espectrômetro de absorção atômica onde prata é monitorada. Nitrogênio foi determinado em sete amostras de referência (três replicatas) com precisão e exatidão comparáveis às do procedimento condutimétrico. O sistema é estável, apresentando apenas pequenas variações em sensibilidade (< 2 %) durante períodos de operação de 4 horas. A velocidade analítica é de aproximadamente 100 h-1 e a repetibilidade das medidas é satisfatória (desvio padrão relativo em geral < 0,02).; A flow-injection system with a AgCl(s) mini-column is proposed for the determination of total nitrogen in plant digests by flame atomic absorption spectrometry. The method is based on Ag+ removal by ammonia through the formation of the diammine argentate(I) complex and further monitoring of the released Ag+. Nitrogen was determined in seven reference samples, in three replicates, with precision and accuracy comparable to the conductimetric procedure. The system is robust...