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