Voltammetric Determination of Iron(III) in Water

Un electrodo serografiado y un electrodo de grafito pirolítico de borde plano sin modificar fueron utilizados en una voltamperometría de onda cuadrada para determinar cantidades traza de Fe(III) en muestras reales de agua de botella mineral.

A square wave voltammetric procedure for the detn. of trace amts. of Fe(III) was developed at an unmodified edge plane pyrolytic graphite (EPPG) electrode and a screen printed electrode (SPE).  This simple procedure was applied to real samples of com. bottled mineral water.  Sensitive results in the micromolar region could be achieved without modification of the electrode.  Using the WHO guideline limits for the Fe(III) concn. in drinking water, recovery percentages at an EPPG gave 103 % and 107 %, and 98.6 % and 95.0 % at a SPE for the 5.36 μM (0.3 mg L^-1) and 53.6 μM (3.0 mg L^-1) addns. of Fe(III), resp.

• Lu, Min; Compton, Richard G.
• Electroanalysis, Ahead of Print

Square wave voltammetric determination of methiocarb insecticide based on multiwall carbon nanotube paste electrode

• Mediante una voltamperometría de onda cuadrada con electrodo de pasta de carbono de estructura de nanotubos se ha estudiado la determinación del insecticida metiocarb en suelos y ríos.

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• Cyclic voltammogram of methiocarb in 0.1 M H₂SO₄ exhibited an irreversible anodic peak at about +1285 mV vs. Ag/AgCl.  Electrooxidn. and detn. of methiocarb in spiked soil, river water, and agrochem. formulation were realized on a newly prepd. carbon-nanotube paste electrode by applying square wave voltammetry (SWV).  The dE _p/dpH value indicated that the oxidn. mechanism involved the coupling of H⁺ with the oxidn. process.  The peak signals were linearly related to methiocarb concn. in the range of 1.5-59.1 mg L^-1 with a detection limit of 0.45 mg L^-1.  The accuracy and selectivity of the proposed method were shown by calcg. the recoveries of methiocarb from soil, river water, and pesticide formulation Mesurol.  The calcd. percent recoveries for soil and river water samples spiked with 30.0 μg g^-1 and 40.0 μg mL^-1 levels were 99.3 ±1.2 and 98.5 ±0.3 at 95% confidence limit, resp.
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• Inam, Recai; Bilgin, Cansu
• Journal of Applied Electrochemistry (2013), 43(4), 425-432

Simultaneous Voltammetric Determination of Captopril and Hydrochlorothiazide on a Graphene/Ferrocene Composite Carbon Paste Electrode

El captopril y la hidroclorotiazida han sido determinadas simultáneamente a través de una voltamperometría de pulso diferencial con un electrodo de pasta de carbono compuesto de grafeno y ferroceno. Los dichos compuestos fueron hallados en muestras farmacéuticas y clínicas. 

In this work, a voltammetric method has been developed for the simultaneous detn. of captopril (CPT) and hydrochlorothiazide (HCT) in pharmaceutical combinations and clin. samples using a graphene/ferrocene composite carbon paste (GR/Fc/CP) electrode.  The electrochem. behaviors of CPT and HCT were individually and simultaneously investigated at the surface of the GR/Fc/CP electrode.  In differential pulse voltammetric (DPV) mode and under optimized exptl. conditions, CPT and HCT gave linear responses over the concn. ranges 1.0-430 μM and 0.5-390 μM (r²>0.99), resp.  The prepd. electrode could be used for simultaneous detn. of CPT and HCT in some real samples.

• Gholivand, Mohammad Bagher; Khodadadian, Mehdi
• From Electroanalysis, Ahead of Print

Voltammetric determination of isoniazid using cyclic renewable mercury film silver based electrode

Un método voltamperométrico catódico basado en un electrodo de plata con película de mercurio cíclica renovable fue investigado para la determinación de isoniazida.

A new cathodic voltammetry method for the detn. of isoniazid based on the cyclic renewable mercury film silver based electrode (Hg (Ag) FE) is presented.  The effects of various factors such as: preconcn. potential and time, pulse height, step potential and supporting electrolyte compn. are optimized.  The calibration graph is linear from 5 nM up to 500 nM (68.55 μgL^-1).  For Hg (Ag) FE with a surface area of 9.7 mm² without time consuming preconcn. the limits of detection LOD and quantification LOQ were 4.1 nM and 10.5 nM of isoniazid, resp.  The repeatability of the method at a concn. level of the analyte as low as 0.5 nM, expressed as RSD is 3.6% (n = 6).  The proposed method was successfully applied in anal. of isoniazid in simple and composed pharmaceutical formulations.

• Szlosarczyk, Marek; Piech, Robert; Bator, Beata Paczosa; Maslanka, Anna; Opoka, Wlodzimierz; Krzek, Jan
• Pharmaceutica Analytica Acta (2012), 3(9), 1000189/1-1000189/5.

Simultaneous differential pulse voltammetric determination of dopamine and uric acid with polycalconcarboxylic acid modified glassy carbon electrode

En este artículo la voltamperometría de pulso diferencial tiene la particularidad de ser utilizada con un electrodo vítreo de carbono modificado con ácido policarconcarboxílico. Los resultados obtenidos son buenos para la determinación simultánea de ácido úrico y dopamina.

• The modified electrode (PCCA/GCE) was prepd. by electrochem. polymn. of calconcarboxylic acid (CCA) on the surface of glassy carbon electrode (GCE).  The electrochem. property of the PCCA/GCE was studied by cyclic voltammetry and AC impedance method.  It was found that in a PBS of pH 6.0, the oxidn. peaks of dopamine (DA) and uric acid (UA) were completely sepd., and the p.d. of the oxidn. peaks attained to a value of 0.14 V.  Based on these findings, a selective method for simultaneous detn. of DA and UA by differential pulse voltammetry was proposed.  Linear relationships between values of oxidn. peak current and concn. of DA and UA were obtained in the ranges of 5.0-43.8 μmol·L^-1 and 5.0-50.0 μmol·L^-1, with their detection limits of 0.2 μmol·L^-1 and 0.5 μmol·L^-1, resp.  The proposed method has been used in simultaneous detn. of DA and UA in DA injections, giving values of RSD's (n = 5) of 2.43% for DA and 2.35% for UA.
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• Huang, Wen-hua; Hou, Bao-qin; Zhang, Lei
• Lihua Jianyan, Huaxue Fence (2012), 48(6), 638-642.

Use of phosphate activated glassy carbon electrode in voltammetric determination of epinephrine

• En este artículo la protagonista es la voltamperometría cíclica, que permite determinar cantidades traza de epinefrina mediante la utilización de un electrodo vítreo de carbono activado con fosfato. 

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• Phosphate activated GCE was prepd. by cyclic voltammetry, and the electrochem. behavior of epinephrine (EP) at this electrode in a phosphate buffer medium of pH 6.0 was studied.  A cyclic voltammetric method for detn. of trace amt. of EP was proposed, by which the interference of ascorbic acid to the detn. of EP was effectively eliminated.  A sensitive oxidn. peak of EP at 0.26 V (vs. SCE) was obsd.  Linear relationship between values of oxidn. peak current (i_pa) and concn. of EP was obtained in the range of 1.0 × 10^-6-1.2 × 10^-5 mol·L^-1, with detection limit (3S/N) of 3.0 × 10^-7 mol·L^-1.  This method was applied to the detn. of EP in injections, giving results in consistency with the labeled values.  Av. recovery of the method found by std. addn. method was 99.7%.
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•  Li, Jin-jin; Wang, Xue-liang; Guo, Xian-hou; Yu, Zhang-yu
• Lihua Jianyan, Huaxue Fence (2012), 48(7), 766-769

Voltammetric determination of trace elements in infusions of medicinal plants

• Para la determinación de elementos traza de importancia biológica (Cu, Zn, Cd, Pb) en hierbas de infusiones se estedió una voltamperometría de pulso diferencial de redisolución aniónica. El método de extracción llevado a cabo fue una combustión en atmósfera de oxígeno asistida por microondas.

• This work deals with the detn. of biol. important trace elements, such as copper, zinc, cadmium, and lead, in herbal infusions.  Black elder flowers (Sambuci flos), birch leaves (Betulae folium), linden flowers (Tiliae flos), peppermint (Menthae herba) and sage (Salviae herba) were used as plant material for the infusion prepns.  The method of differential pulse anodic stripping voltammetry was developed and applied for the detn. of the above mentioned trace elements in digests of plant materials as well as in herbal infusions.  The method of choice for digest prepn. was the microwave assisted combustion in an oxygen atm.  Parameters of voltammetric measurements were optimized.  The concns. of particular trace elements found in the digests; 36.6-226 μg.g^-1 for zinc, 3.78-6.96μg.g^-1 for copper, 1.59-0.39μg.g^-1 for lead and 0.208-0.106μg.g^-1 for cadmium were compared with concns. found in infusions: 32.7-1.86μg.g^-1 for zinc, 1.26-0.417μg.g^-1 for copper, 0.088-0.049μg.g^-1 for lead, and 0.076-0.021 μg.g^-1 for cadmium.  The ratios of the amts. for particular trace element transferred from plants into infusions ranged from 4% to 18%.
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• Sucman, E.; Matzke, F.
• Folia Veterinaria (2012), 56(3), 16-20

Novel nanostructured electrochemical sensor for voltammetric determination of N-acetylcysteine in the presence of high concentrations of tryptophan

La voltamperometría de onda cuadrada utilizada como un novedoso sensor electroquímico de nanoestructura (electrodo de pasta de carbono químicamente modificado con nanotubos de multiparedes), ha resultado útil en la determinación de N-acetilcisteína en muestras de orina y drogas.

• A carbon paste electrode chem. modified with multiwall nanotubes and ethynylferrocene (ETFc) was used as a selective and sensitive electrochem. sensor for the detn. of minor amts. of N-acetylcysteine (N-AC) in the presence of a high concn. of tryptophan (Trp).  Square wave voltammetry (SWV) of N-AC at the modified electrode exhibited linear dynamic range with a detection limit (3 s) of 0.08 μmol L^-1.  The sepns. of anodic peak potentials of N-AC and Trp reached 400 mV using SWV.  With good selectivity and sensitivity, the present method provides a simple method for selective detection of N-AC in real samples such as drug and urine.
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• Fouladgar, Masoud; Karimi-Maleh, Hassan; Hosseinzadeh, Rahman
• Ionics (2013), 19(4), 665-672.

Carbon paste electrode prepared from chemically modified multiwall carbon nanotubes for the voltammetric determination of isoprenaline in pharmaceutical and urine samples

La voltamperometría con electrodo de pasta de carbón con nanotubos de carbono de multiparedes modificados químicamente (con N-(3,4-dihydroxyphenethyl)-3,5-dinitrobenzamide) ha vuelto a ser estudiada para el análisis de un compuesto en cantidades traza. En este artículo se determina isoprenalina en muestras de orina y farmacéuticas

A carbon paste electrode with added multiwall carbon nanotubes chem. modified with N-(3,4-dihydroxyphenethyl)-3,5-dinitrobenzamide was used as the electrochem. sensor for the detn. of trace amts. of isoprenaline.  The modified electrode showed good electrocatalytic activity for the anodic oxidn. of isoprenaline, which was due to a substantial decrease in the anodic overpotential.  Under the optimum conditions, measurements using square wave voltammetry had a linear range in the range of 0.3 to 125.0 μmol/L of isoprenaline and a detection limit of 0.1 μmol/L.  The diffusion coeff. and kinetic parameters were detd. using electrochem. methods.  The relative std. deviation for seven successive assays of 1.0 and 20.0 μmol/L isoprenaline were 1.9% and 2.4%, resp.  This electrochem. sensor was successfully applied for the detn. of isoprenaline in human urine and injection soln. samples.

• Ensafi, Ali A.; Bahrami, Hajar; Karimi-maleh, Hassan; Mallakpour, Shadpour
• Cuihua Xuebao (2012), 33(12), 1919-1926

A simple method for voltammetric determination of trace amounts of selenium in diverse matrices

La determinación de cantidades traza de Se en aguas industriasles y en tabletas de vitaminas es posible mediante un método muy simple de voltamperometría basado en el diferencial de impulsos de reducción polarográfica de Se (IV).

"A simple and convenient method is described for the determination of low concentration selenium in samples of industrial waste and vitamin tablet. The method is based on the differential pulse polarographic reduction of Se (IV) in presence of alanine in ammonium chloride medium. Linearity of the calibration curve was achieved upto 44ppm with a limit of determination of 5 μg/L. Major metal ions copper, lead and zinc did not interfere."

• Kherwa, V.; Dubey, S.
• From Research Journal of Recent Sciences (2013), 2(ISC-2012), 51-54

Electrochemical Behavior and Voltammetric Determination of Diclofenac at a Multi-Walled Carbon Nanotube-Ionic Liquid Composite Modified Carbon Ceramic Electrode

La determinación de diclofenaco se realiza por voltamperometría, mediante la superficie de un electrodo carboncerámico modificado con nanotubos de carbono de multipared y una composición líquida iónica.

This work describes the electrochem. behavior of diclofenac on the surface of a carbonceramic electrode (CCE) modified with multi-walled carbon nanotubes (MWCNT) and an ionic liq. (IL) composite.  The MWCNT-IL composite showed an enhancement effect in the electro-oxidn. of diclofenac with respect to a bare carbon ceramic electrode.  Based on the exptl. outcomes, a possible mechanism for the electro-oxidn. of diclofenac is proposed and discussed.  Under the optimized exptl. conditions, the MWCNT-ILCCE showed a linear response to diclofenac over the concn. range 50 nM-20 μM with a detection limit of 27 nM.  The developed diclofenac sensor showed good stability, sensitivity, and reproducibility in the measurement of diclofenac in human blood plasma samples.

• Razmi, Habib; Sarhang-Zadeh, Kianoush; Mohammad-Rezaei, Rahim
• Analytical Letters, Ahead of Print

Anodic stripping voltammetric analysis of lead, cadmium and copper in the Jordan river, Utah

El plomo ha sido, una vez más, determinado mediante voltamperometría. En este estudio, además de plomo, se determina cadmio y cobre en el río Jordan (Utah) mediante voltamperometría de redisolución anódica.

This project is an ongoing multifaceted investigation of the Jordan River.  The study's intent is to monitor and asses the overall condition of the river from Utah Lake to the Great Salt Lake.  Samples of river and pond water, typical vegetation such as cattails, and some soils have been collected with ref. to sites along the river that may serve as sites for the introduction of waste and other contaminants.  These samples have so far been examd. with respect to temp. and dissolved oxygen at the sampling point.  Two river samples, one pond sample, and plant sample have been analyzed by ICP-MS for 20 different metals.  The levels of Lead, Cadmium, and Copper have been detd. by anodic stripping voltammetry at the ppb level in a variety of other water samples from the river.  The results of these measurements are disused and presented Geospatially.

Iles, Peter; Thurman, Chris; Warren, Joseph; Sanders, Wesley; Richards, Sydney; Parker, Lauren; Valcarce, Ron; Giddings, Luther; Alvarez, Mary; Bastian, Neil Abstracts of Papers, 243rd ACS National Meeting & Exposition, San Diego, CA, United States, March 25-29, 2012 (2012), ANYL-53

Voltammetric determination of carbidopa using a modified multiwall carbon nanotube paste electrode

Esta vez la voltamperometría se utiliza para determinar carbidopa, con la particularidad de que se usa un electrodo de pasta de nanotubos de carbono modificado. El estudio se lleva a cabo con voltamperometría cíclica y con voltamperometría de onda cuadrada.

A modified carbon nanotubes paste electrode (MCNTPE) was used for the sensitive voltammetric detn. of carbidopa (CD) in buffer soln. using cyclic voltammetry (CV), square wave voltammetry (SWV) and chronoamperometry (CHA).  The diffusion coeff. (D = 2.62 × 10-5 cm2 s-1) and the kinetic parameter such as the electron transfer coeff. (α = 0.37) of CD oxidn. at the surface of MCNTPE was detd. using electrochem. approaches.  It has been found that under an optimum condition (pH 9.0), the oxidn. of CD at the surface of the modified electrode occurs at a potential about 100 mV less pos. than that of an unmodified carbon nanotubes paste electrode.  SWV of CD at the modified electrode exhibited linear dynamic range with a detection limit (3σ) of 0.4μM.  Finally, this modified electrode was also examd. for the detn. of CD in urine samples.

Mohadesi, Alireza

International Journal of Electrochemical Science (2012), 7(3), 2430-2439

Differential pulse voltammetric analysis of lead in vegetables using a surface amino-functionalized exfoliated graphite nanoplatelet chemically modified electrode

En este artículo un tipo de voltamperometría de pulso diferencial fue utilizada para determinar plomo(II) en vegetales como el repollo. Para este análisis se usa un electrodo modificado químicamente con una superficie amino funcional exfoliada de grafito nanoplatelet.

A surface amino-functionalized (CONH2) exfoliated graphite nanoplatelet (xGnP) bismuth-modified electrode (CONH2xGnP/glassy carbon electrode GCE) for the detn. of lead was developed and characterized.  The hybrid material was characterized by Fourier transform IR spectroscopy (FTIR) and SEM (SEM).  The electrochem. properties of the CONH2xGnP bismuth-modified electrode were characterized by a phys. deposition method, depositing the film on a graphite electrode.  The differential pulse response was linear over the Pb(II) concn. range of 0.005-0.045 μg L-1, with a limit of detection of 0.001 μg L-1, and the linear regression equation was y = 3.75x + 0.73.  In vegetable juice (cabbage), the current increased linearly relative to the Pb(II) concns. over the concn. range 0.005-0.035 μg L-1 with the corresponding linear regression equations: y = 13.06x + 0.46, R2 = 0.9970.

 Ion, Ion; Ion, Alina Catrinel                                                      

 Sensors and Actuators, B: Chemical (2012), 166-167, 842-847.  

A comparative study on carbon paste electrodes modified with hybrid mesoporous materials for voltammetric analysis of lead (II)

En el siguiente artículo se estudia el análisis voltamperométrico del plomo (II) mediante electrodos de pasta de carbono modificados con materiales híbridos mesoporosos. Se tratra de un voltamperometría de redisolución-adsorción.



We have chem. functionalized four types of ordered mesoporous silicas (referred to as MPS1-MPS4) with 5-mercapto-1-methyltetrazole (MTTZ), and have incorporated these materials into carbon paste electrodes (CPEs) to obtain sensors for the detn. of Pb(II) ion in aq. media by adsorptive stripping voltammetry.  Materials and MPS1-MPS4, were characterized by nitrogen adsorption-desorption measurements, X-ray diffraction, transmission electron microscopy, SEM and elemental anal.  The effect of the mesostructure of the MPS on the performance of the sensors was evaluated with respect to linear ranges, sensitivities, selectivities, precision and limits of detection.  The CPE modified with MPS1 (a silica with mesopores of 37 Å in diam. and pseudo-spherical particle morphol.) exhibited the best inter-electrode reproducibility and sensitivity, a linear range between 1 and 30 ppb and a limit of detection of 0.8 ppb.  The CPE modified with MPS4 (a silica with hexagonal mesopores of 58 Å in diam., cylindrical particle morphol. and bigger size) exhibited the poorest inter-electrode reproducibility and sensitivity, a linear range between 5 and 100 ppb, and a limit of detection of 2.6 ppb.  The differences in the voltammetric responses to Pb(II) therefore appear to result from differences in the coating of the inner surface with MTTZ, the pore diam., and the particle morphol. as well as the size of the hybrid MPS.  As consequence of its highest inter-electrode reproducibility and sensitivity, good linear range and low limit of detection, MPS1 can be selected as the better material to prep. modified CPE for Pb(II) detn. in aq. media by adsorptive stripping voltammetry.

Sanchez, Alfredo; Morante-Zarcero, Sonia; Perez-Quintanilla, Damian; del Hierro, Isabel; Sierra, Isabel Journal of Electroanalytical Chemistry (2013), 689, 76-82

En esta publicación se muestra el análisis voltamperométrico no como una técnica cuantitativa, si no que se utiliza la información voltamperométrica para poder determinar la coordinación y las propiedades de transferencia electrónica del Ni(II) a distinta acidez.

The coordination chem. of Ni(II) in the ionic liq. aluminum chloride : 1-ethyl-3-Me imidazolium chloride (EMIC) has been detd. using visible absorption spectrophotometry.  By dissolving nickel chloride (NiCl2) in Lewis acidic and basic ionic liqs. and observing the resultant spectra and voltammetric information, one can det. the coordination and electron-transfer properties of Ni(II) at the various acidities.  The optical data indicate the formation of tetrahedral NiCl42- in the ionic liq. with excess EMIC (basic melt, NAlCl3 < 0.5) with absorption maxima at 659 and 707 nm.  In acidic melts (NAlCl3 > 0.5), the wavelength of max. absorbance shifts to 462 nm.  This dramatic change in the visible spectrum is indicative of a change in the coordination of Ni(II) from tetrahedral (basic) to octahedral (acidic) geometry, changes which are mirrored in the cyclic voltammetry data of the same samples.  Studies in the neutral melt are also presented here. 

Parker, J. F.; Cheek, G. T.; Roeper, D. F.; O'Grady, W. E.

 ECS Transactions (2012), 41(36, Physical and Analytical Electrochemistry in Ionic Liquids 2), 23-33

Direct Voltammetric Determination of Total Iron with a Gold Microelectrode Ensemble

En este trabajo se habla de una voltamperometría cíclica con un conjunto de microelectrodos de oro para determinar la cantidad de hierro que hay en una muestra debido al comportamiento redox del Fe (II)/(III).

    The behavior of the Fe(II)/(III) redox system at a Au microelectrode ensemble (Au-MEE) based on a solid composite by means of direct and cyclic voltammetric anal. (VA) is reported.  With a simple electrode activation and sample prepn., the influence of dissolved org. substances was eliminated, providing highly sensitive results.  The anal. signal was based on the max. cathodic current (I) of the 1st deriv. (dI/dE), and Fe detn. within the 0.002-0.04 mg L-1 range was studied.  A sensitive LOD (3σ) value of 0.7 μg L-1 for total Fe concn. was calcd.; total Fe detn. in different waters was shown.

   Zakharova, E. A.; Elesova, E. E.; Noskova, G. N.; Lu, M.; Compton, R. G.

 Electroanalysis (2012), 24(11), 2061-2069

Electrochemical method of base electrolyte imitating waste water for voltammetric analysis of copper ions

En este estudio se determinan iones de cobre voltamperométricamente en un agua residual simulada añadiendo a la muestra una cantidad definida de cloruro potásico.

  The invention relates to simulated soln. sample imitating waste water compn. is added to the base electrolyte soln. of potassium chloride 0.05 M, which is pretreated with electrochem. method.  The invention allows for reducing anal. time, analyzing small samples and increasing anal. sensitivity.

 Perevezentseva, D. O.; Chernyshova, N. N.

 Russ. (2012), RU 2453638 C1 20120620

Analysis and design of a multisensory array for explosive substances based on solid electrodes

Fue creado un dispositivo para detectar explosivos. Este dispositivo consta de un electrodo virtual de un metal y una voltamperometría de pulso diferencial. Entre las sñales electroquímica y análisis quimiométricos es posible diferenciar productos explosivos de otras substancias.

The detection of explosives and explosive related compds. is a subject of importance in several areas including environmental health, de-mining efforts (land and sea) and security and defense against terrorist activity.  The use of electrochem. methods is particularly attractive as many common explosives contain suitable chem. groups to be detected using electrochem. methods.  The electrochem. detection of explosives and related compds. in soln. using a virtual metal electrode array and differential pulse voltammetry was achieved.  The multiple sets of voltammetric data were integrated using multivariate anal. and matched with known substances present in explosives.  Seven explosive substances: 2,4-initrotoluene, 2,6-dinitrotoluene, 3,4-dinitrotoluene, 2-nitrotoluene, octogen (HMX), pentaerythritol tetranitrate (PETN), trinitrotoluene (TNT) and cyclonite (RDX) and a taggant agent 2,3-dimethyl-2,3-dinitrobutane (DMNB) were subjected to anal. using four solid electrodes, namely glassy carbon, silver, gold and platinum in saline aq. solns. to mimic an aquatic environment.  The results obtained in Differential Pulse Voltammetry (DPV) from the different expts. with each electrode were combined to produce a single voltammogram, which was subjected to chemometric anal. using Partial Least Squares (PLS) and Principle Component Anal. Non-Iterative Partial Least Squares (PCA-NIPALS).  A combination of the electrochem. signals obtained together with the use of chemometric anal. made it possible to discriminate between explosives and their mixts. and also to quantitate their concn. in saline solns.  These combinations created a math. array, which clearly separates the explosives, even if the electrochem. information is buried or mixed with the electrode background noise.

Baron, Mark; Barret, Richard; Rodriguez, Jose-Gonzalez

Proceedings of SPIE (2012), 8545(Optical Materials and Biomaterials in Security and Defence Systems Technology IX), 85450H/1-85450H/8.

Iron(III) complexes of ethylenediamine derivatives of aminophenol ligands as models for enzyme-substrate adducts of catechol dioxygenases

En este trabajo se sintetizaron complejs de Fe (III) de de derivados de etilendiamina de ligandos aminofenol como modelos de enzima-sustrato aductos de dioxigenasa catecol. Se analizaron, entre otras técnicas, por voltamperometría cíclica.

 

In the present work, six N,N'-dimethylethylenediamine derivs. of substituted aminophenol ligands (H₂L^NEX, X: C, B, M, BM, Bu and OB) were synthesized by a convenient, green procedure.  The mentioned ligands were characterized by ¹H NMR and IR spectroscopies. iron complexes (FeL^NEX, X: C, B, M, BM, Bu and OB) of mentioned ligands, have been synthesized and characterized by IR, UV-Vis, elemental anal., single crystal X-ray diffraction, magnetic susceptibility studies and cyclic voltammetry techniques.  X-ray structure anal. has revealed that Fe(III) centers were surrounded by two phenolates, two amine nitrogens and two oxygen atoms of acetylacetonate ligand similar to the proposed catechol-bound intermediate for catechol dioxygenase.  The variable temp. magnetic susceptibility indicates paramagnetic iron(III) in monomer complexes.  All complexes undergo a metal-centered redn., and a ligand-centered oxidn.

Karimpour, Touraj; Safaei, Elham; Wojtczak, Andrzej; Jaglicic, Zvonko; Kozakiewicz, Anna                                 

Inorganica Chimica Acta (2013), 395, 124-134

Voltammetric analysis of sun-block preparations containing octocrylene and its association with 2-Hydroxy-4-methoxybenzophenone and octyl methoxycinnamate

En este artículo se trata un método voltamperométrico basado en una voltamperometría de onda cuadrada para la determinación de un agente de filtro solar de octileno de forma individual y simultánea a la determinación de 2-Hydroxy-4-methoxybenzophenone (BENZO-3) y octyl methoxycinnamate (OMC).

In this work, an adsorptive cathodic stripping voltammetric method based on square wave voltammetry (SWV) was developed for detn. of the sunscreen agent octocrylene (OCR) individually and simultaneously with 2-Hydroxy-4-methoxybenzophenone (BENZO-3) and octyl methoxycinnamate (OMC).  All voltammetric expts. were conducted in a mixt. 0.04 mol L- 1 BR buffer: EtOH (80:20, v:v) using a hanging mercury drop electrode (HMDE) as working electrode.  The proposed method could be successfully used to analyze com. sun-block prepns. contg. OCR alone and combined with (BENZO-3) and OMC.  For all analyzed samples, the voltammetric method has allowed fast, simple and reliable detn. of these sunscreen agents with minimal sample pre-treatment requirements.

Ferreira, Valdir S.; Junior, Joao B. G.; Oliveira, Celia Maria S. C.; Takeuchi, Regina M.; Santos, Andre L.; Trindade, Magno A. G.

Microchemical Journal (2013), 106, 378-383.

Voltammetric analysis with the use of a novel electro-polymerized graphene-nafion film modified glassy carbon electrode: Simultaneous analysis of noxious nitroaniline isomers

Se realizó un análisis voltamperométrico para los isómeros nocivos de la nitroanilina comprobando la eficacia de una nueva película electropolimerizada modificadora de un electrodo vítreo de carbón.

A new modified electrode was constructed by the electro-polymn. of 7-[(2,4-dihydroxy-5-carboxybenzene)azo]-8-hydroxyquinoline-5-sulfonic acid (DHCBAQS) at a graphene-nafion modified glassy C electrode (GCE).  The construction process was performed stepwise and at each step the electrochem. characteristics were studied particularly with respect to the oxidn. of the 3 noxious analytes, 2-nitroaniline (2-NA), 3-nitroaniline (3-NA), 4-nitroaniline (4-NA); the electrode treated with the fluorescence reagent DHCBAQS performed best.  At this electrode, the differential pulse voltammetry peak currents of the 3 isomers increased linearly with their concns. of 0.05-0.60 μg/mL, and their corresponding limits of detection (LODs) were all ∼0.022 μg/mL.  Satisfactory results were obtained when this electrode was applied for the simultaneous quant. anal. of the nitroaniline isomer mixts. by principal component regression (PCR) and partial least squares (PLS) as calibration methods (relative prediction error (PRET) 9.04 and 9.23%) and av. recoveries 101.0 and 101.7%, resp..  The above novel poly-DHCBAQS/graphene-nafion/GCE was used for the simultaneous anal. of the 3 noxious nitroaniline isomers in water and wastewater.

Lin, Xiaoyun; Ni, Yongnian; Kokot, Serge

Journal of Hazardous Materials (2012), 243, 232-241

Electrochemical Detection of Ammonia in Aqueous Solution Using Fluorescamine: A Comparison of Fluorometric Versus Voltammetric Analysis

En este estudio se comparan dos métodos diferentes para la determinación de amoníaco en soluciones acuosas; la espectroscopía de fluorescencia frente a un análisis voltamperométrico del amoníaco en solución acuosa en reacción con fluorescamina. se encontró que los límites de detección eran similares en ambos métodos.

Fluorescamine is a non-fluorescent reagent widely used for the quant. detn. o f primary amines by fluorescence spectroscopy as it reacts readily with primary amines to form a fluorescent product.  In this work, a new sensitive voltammetric method for the detection of ammonia in aq. soln. by the reaction with fluorescamine has been developed.  First, the electrochem. behavior of fluorescamine in the absence and presence o f ammonia was investigated in 0.1 mol·L-1 borate buffer soln. (pH 9.0) by cyclic voltammetry using a glassy carbon (GC) electrode.  As for fluorescamine itself, a well-defined irreversible oxidn. peak could be obsd. at ca. 0.70 V vs. SCE.  When ammonia was added to the fluorescamine soln., another irreversible oxditaion peak corresponding to the oxidn. o f the reaction product formed between fluorescamine and ammonia could be obsd. at ca. 0.46 V vs. SCE.  Upon the addn. of ammonia, the oxidn. peak o f fluorescamine became smaller while the oxidn. peak o f the reaction product formed increased in height, due to the stoichiometric chem. consumption o f fluorescamine by ammonia and the formation o f the product during the reaction, resp.  These two anodic peaks corresponding to the oxidn. of fluorescamine and its fluorescent product formed were then used for the quant. detection o f ammonia, explored by square wave voltammetry and by fluorescence spectroscopy.  The square wave voltammetric response o f the reaction product formed showed a linear response over ammonia concn. range o f 0 to 60 μmol-L-1.  The limits o f detection (LOD) was found to be 0.71 μmol·L-1 and 3.17 μmol-L-1 detd. based upon Signal/Noise (S/N) = 3 and 3cr, resp. These limits o f detection are similar to those obtained with the fluorometric method.

Panchompoo, Janjira; Compton, Richard G.

Dianhuaxue (2013), 18(5), 437-449

Determination of inorganic phosphate by electroanalytical methods: A review

El siguiente artículo se trata de un resumen de los métodos electroanalíticos utilizados hasta ahora para la determinación de fosfatos escrito por Sheela Berchmansa, Touma B. Issa y Pritam Singh. Como es de esperar, habla de varios métodos voltamperométricos: métodos voltamperométricos basados en reconocimiento supramolecular de fosfatos, voltametría en la interfaz entre dos interfaces de electrolitos inmiscibles y voltamperometría de modulación térmica.

Analytica Chimica Acta 729 (2012) 7– 20

Sheela Berchmansa, Touma B. Issa y Pritam Singh

DETERMINACION DE HERBICIDAS N1TROFENOLES Y S-TRIAZINAS POR VOLTAMPEROMETRIA DE ADSORCION-REDISOLUCION

En el siguiente estudio se han desarrollado métodos para determinar los herbicidas dinoseb, metoprotrina y terbutrina empleando polarografía diferencial de impulsos y voltamperometría de absorción-redisolución. Este artículo está realizado por María Pedrero Muñoz de la Universidad Complutense de Madrid.

http://pendientedemigracion.ucm.es/BUCM/tesis/19911996/X/0/X0025401.pdf

Comparison of Analytical Methodologies for Aluminium Determination in Hemodialysis Fluids

Para cuantificar el aluminio en fluidos utilizados en hemoálisis renal se usaron dos metodologías; voltamperometría de adsorción-onda cuadrada y la adsorción electrotérmica. En este artículo Miriam B. uirós, perteneciente al Centro de Electroquímica y energía química de la Universidad de Costa Rica, relata los experimentos llevados a cabo.

Portugaliae Electrochimica Acta 2009, 27(2), 69-76

http://www.scielo.oces.mctes.pt/pdf/pea/v27n2/v27n2a01.pdf

Cyclic voltammetry

El video explicativo de la voltamperometría cíclica que se muestra a contisnuación fue realizado por Kyung Mi Kim, Christian Findley y Nefer Ortega.

development of a Voltammetric Method to Determine Molybdenum in Food Grains

Alvarado-Gámez, León-Rojas y Espinoza-Castellón, procedentes del Centro de Electroquímica y Energía química y de la Escuela de química  de la Universidad de Costa Rica, desarrollaron una técnica voltamperométrica de barrido lineal para determinar molibdeno en agua y cereales con preconcentración adsortiva de un molibdeno (VI).

Portugaliae Electrochimica Acta 23 (2005) 393-402

http://www.scielo.oces.mctes.pt/pdf/pea/v23n3/v23n3a04.pdf

REDUCCION DEL OXIGENO SOBRE CALCOSITA, PIRITA Y GALENA EN MEDIO ALCALINO

La electroreducción del oxígeno fue investigada a pH = 14 sobre electrodos de calcosita, pirita y galena mediante voltamperometría cíclica y por voltamperometría estacionaria usando una celda electroquímica de flujo de doble canal.

http://www.scielo.cl/scielo.php?pid=S0366-16442000000300015&script=sci_arttext

JUAN ORTIZ, SALVADOR BARBATO Y JUAN LUIS GAUTIER 

Departamento de Química de los Materiales, Facultad de Química y Biología, 

Universidad de Santiago de Chile. 

Departamento de Química, Facultad de Ciencias Básicas, 

Universidad de Antofagasta

La voltamperometría de micropartículas en la diferenciación de óxidos y oxihidróxidos de hierro

La técnica de voltamperometría de micropartículas se considera apropiada para estudios ambientales y puede ser relacionada con otras técnicas de magnetismo ambiental debido a que es altamente sensible a la detección de especies débilmente magnéticas, como la hematita y la goethita (antiferromagnéticas) y en menor medida a las fuertemente magnéticas, como la magnetita (ferrimagnética). 

El artículo realizado por Rico, Y, Elsner, C.I. y Bidegain, J.C fue publicado en Revista 

de la Asociación Geológica Argentina, v.62 n.3 Buenos Aires jul./sep. 2007

http://www.scielo.org.ar/scielo.php?script=sci_arttext&pid=S0004-48222007000300009

voltamperometría cíclica y voltamperometría de pulso diferencial.

En el siguiente artículo se refleja un estudio en los avances en la detección simultánea de dopamina, ácido ascórbico y serotonina mediante voltamperometría cíclica y voltamperometría de pulso diferencial empleando electrodos de puntas de lapicero modificados con nanotubos.

http://celectroquimica.cucei.udg.mx/doc/papers/107.pdf


Los autores de este artículo; Albino-Navarro G., Galván-Valencia M., Morales-Acosta D. y Durón-Torres S. M, trabajan en la Unidad Académica de Ciencias Químicas de la Universidad Autónoma de Zacatecas y en el Centro de Investigación y Desarrollo Tecnólogico en Electroquímica.

Differential Stripping Voltammetry

En el siguiente video Amy Hrdina explica como hacer un determinado tipo de voltamperometría (differential pulse anodic stripping voltametry), explica los componentes del aparato y como se utiliza, además de hacer una demostración práctica.

Effect of structure on the electrochemical oxidation rate of copper and nickel sulfides

Nuevamente se utiliza la voltamperometría para el estudio de una oxidación electroquímica, pero esta vez para los sulfuros de Cu y Ni.

Synthesized samples were crystd. at 10-1000 K/s (νcooling) to study the effect of sulfides structure on the electrochem. oxidn. rates.  The methods of x-ray, optical and electronic microscopy were used to analyze the phase compn., and the methods of voltamperometry and chronoamperometry were used to study the laws of electrochem. oxidn.  Slow cooling of the samples with sulfide phase (Cu1,96S, Ni3S2) leads to crystn. of the metal (Ni, Cu).  High cooling rate leads to crystn. of nonequil. phases, increasing of proportion of the sulfide phase and decreasing of metallic component up to complete disappearance.  Electrochem. oxidn. of Cu and Ni sulfides proceeds stepwise: Me2S → Me2-XS → Me1 + XS → MeS → Me2+ + S.  Expts. revealed the rates of electrochem. oxidn. of granular sulfides that exceed the rates established for the slowly cooled samples.  The rates of the electrochem. oxidn. of Ni3S2 at potential of 1500 mV are 8.8 × 10-8 g/s·mm2 (at νcooling = 10 K/s) and 1.3 × 10-7 g/s·mm2 (at νcooling = 1000 K/s).  The rates of the electrochem. oxidn. of Cu2S at potential of 1000 mV are 2.8 × 10-8 g/s·mm2 (at νcooling = 10 K/s) and 4.3 × 10-8 g/s·mm2 (at νcooling = 1000 K/s).  The forming of a passivation layer effects the rate of the electrochem. oxidn. of Cu sulfide and Ni sulfide.  Nonequil. phase compn. and refinement provide greater reactivity of sulfides in the conditions of anodic polarization.  The oxidn. and passivation of metallic phase along with sulfide phases proceed from the surface of Me2S - Me alloys.  As for the samples crystd. at 1000 K/s only anodic oxidn. of sulfides occurs due to a lack of metallic phase.  The compns. of passivation films and potentials providing the extn. of S in the elemental state from the sulfides crystd. at high rates were detd.

 Diffusion and Defect Data--Solid State Data, Pt. A: Defect and Diffusion Forum (2012), 326-328(Diffusion in Solids and Liquids VII), 383-387

 Nechvoglod, O. V.; Selivanov, E. N.; Mamyachenkov, S. V