Electrochemical studies of zinc in zinc–insulin solution

Barbosa, Rui M.; Rosário, Luı́s M.; Brett, Christopher M. A.; Oliveira-Brett, Ana Maria

doi:10.1039/an9962101789

Cited by 13 publications

(10 citation statements)

References 18 publications

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“…Other species that can be oxidized or promote anticipation of mercury oxidation (halides, pseudohalides, sul®de, thiols among others) should be determinable. To avoid oxygen removal in the extended negative potential window provided by the mercury drop, an alternative to be examined is square wave voltammetry, formerly applied to other electrodes [22,26,27]. …”

Section: Resultsmentioning

confidence: 99%

A Batch Injection Analysis System for Ascorbic Acid Determination Using Amperometric Detection on a Sessile Mercury Drop Electrode

Donato

Pedrotti

Gutz³

1999

Electroanalysis

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A batch injection analysis (BIA) system, which uses an automatic mercury electrode (AME) as an amperometric detector, is described. The capillary of this AME was adapted in an inverted position through the bottom of a simple cylindrical electrochemical cell, in order to generate more stable sessile drops and to grant free access for the tip of the programmable micropipettor. The BIA system was evaluated by using the electrochemical oxidation of L-ascorbic acid to dehydroascorbic acid on the sessile mercury drop electrode. Acetate buffer solution (50 mM, pH 4.8) was used as supporting electrolyte. The working electrode was operated at 0.230 V (vs. Ag/AgCl). The effect of the dispensing rate, of the dispensed volume, of the distance between the mercury drop and the pipettor tip, as well as of the solution level in the cell were evaluated. Injections of 50 mL were suitable to reach a detection limit of about 2.5 mM (450 ppb). At the 50 mM ascorbic acid level, an RSD of 1.6 % (N 35) was observed with or without mercury drop renewal between injections. A frequency of 300 injections per hour may be reached when the drop is renewed sporadically. The new BIA method was applied to the determination of ascorbic acid in packedacanned tropical fruit juices. Selectivity was granted by differential measurements of the peak current before and after exposure of samples to ascorbate oxidase (from cucumber).

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Section: Resultsmentioning

confidence: 99%

A Batch Injection Analysis System for Ascorbic Acid Determination Using Amperometric Detection on a Sessile Mercury Drop Electrode

Donato

Pedrotti

Gutz³

1999

Electroanalysis

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“…In the earlier studies, the feasibility of anodic stripping voltammetry [52] and adsorptive stripping voltammetry was demonstrated [53]. Low levels of zinc in zinc-insulin solutions were quantified by square-wave voltammetry, in presence of dissolved oxygen [54]. In the subsequent studies, the electrodeposition of thin mercury films inside polymeric films of Nafion [55, 56, 59 ± 61], poly(ester sulfonic acid) [57], poly(vinyl sulfonic acid) alone and associated to different polymers [58] was optimized.…”

Section: Voltammetrymentioning

confidence: 99%

Batch Injection Analysis: An Almost Unexplored Powerful Tool

2004

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The main purpose of this review is to report the development and potentialities of batch injection analysis (BIA) and call the attention of researchers about the power of this (until now) almost unexplored tool. The text focuses on the concepts and potentialities of BIA combined with other techniques for analytical purposes. The association of BIA with amperometry, potentiometry, voltammetry, calorimetry, fluorescence and spectrophotometry is presented and important aspects related with each technique are discussed. Some aspects comparing the similarities and differences between BIA, FIA and wall-jet are presented along the text.

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“…The lower detection limit of determinable concentrations on electrodes made of a single unmodified carbon or graphite fiber is 10 −7 -10 −9 M [202 -212]. Still lower detection limits of 10 −8 -10 −10 M were achieved with For abbreviations aside from those defined here, see Tables 1 to 3 GF graphite fiber, CF carbon fiber, GCF glassy-carbon fiber, CFA carbon fiber array, CMEA carbon microelectrode array, CNTA carbon nanotubes array mercury-, gold-, and bismuth-modified ME, MEA and CNTA [213][214][215][216][217][218][219][220][221][222][223][224][225][226][227]; see Table 4.…”

Section: Carbon Microelectrodesmentioning

confidence: 99%

Modified carbon-containing electrodes in stripping voltammetry of metals. Part II. Composite and microelectrodes

Stozhko

Малахова

Fyodorov

et al. 2007

J Solid State Electrochem

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The second part of the review, which covers modified carbon-containing electrodes, describes composite and microelectrodes. Electrodes made of commercial and laboratory carbon-containing composite materials are discussed. Impregnated and thick-film electrodes and microelectrodes made of carbon fibers form a separate group. Various modifiers and methods of electrode modification are presented. Prospects for the future development of solid-state modified electrodes are considered. [12][13][14][15][16]. In most cases, electrodes of these materials are modified by metal films (mercury, copper, and bismuth), molecularly imprinted TiO 2 [17]. The occurrence in the last decade of new types of carbon materials "from carbon nanotubes to edge plane pyrolytic graphite" [18,19] has significantly changed the scope and sensitivity of electroanalytical methods for the measurement of diverse targets from metals ions to biological markers. Investigators considered in detail electrochemical characteristics [20] and practical use [21] of the "edge" plane pyrolytic graphite, which proved to have a wider interval of working potentials and a low detection limit as compared to those of the basal pyrolytic graphite and GC. For example, in situ bismuth film modified edge plane pyrolytic graphite electrode was successfully applied to the ultra trace simultaneous determination of cadmium(II) and lead(II) with detection limit 5.5·10 −10 and 4·10 −10 M, respectively [22].Synthetic diamonds (nitrogen-[23, 24] and boron-doped ) have come into use quite recently for electrochemical measurements. In particular, a gold-coated, borondoped, diamond thin-film electrode was used for total inorganic arsenic detection in real water samples [50]. Unlike properties of other carbon materials, which are widely used in electroanalysis, properties of synthetic diamonds became the subject of comprehensive study just about 10 years ago. The research was hindered by two circumstances: shortage of the material and the absence of conduction. The situation radically changed with the advent of highly efficient methods for growing of polycrystalline diamond compounds.A more efficient separation, accumulation, and determination of components is achieved with electrodes of composite materials made of graphite, carbon, glassy carbon, or diamond powders and binders such as paraffin, epoxy resins, methacrylate, silicon, styrene-acrylonitrile copolymer, polyester, and silica gel. The reviews [51][52][53][54] deal with properties and applications of various composite J Solid State Electrochem

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Electrochemical studies of zinc in zinc–insulin solution

Cited by 13 publications

References 18 publications

A Batch Injection Analysis System for Ascorbic Acid Determination Using Amperometric Detection on a Sessile Mercury Drop Electrode

A Batch Injection Analysis System for Ascorbic Acid Determination Using Amperometric Detection on a Sessile Mercury Drop Electrode

Batch Injection Analysis: An Almost Unexplored Powerful Tool

Modified carbon-containing electrodes in stripping voltammetry of metals. Part II. Composite and microelectrodes

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