Comparison of adsorptive stripping voltammetry (AdSV) and capillary zone electrophoresis (CZE) for the trace determination of selected metal ions, chelated with 2-(5′-bromo-2′-pyridylazo)-5-(diethylamino)phenol (PADAP)

Oxspring, Darren A.; Maxwell, T.J.; Smyth, W. Franklin

doi:10.1039/ai9953200489

Cited by 8 publications

(2 citation statements)

References 9 publications

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“…[10][11][12] It was reported that 5-Br-PADAP formed a complex with Pd(II) with the mole ratio of 1:1. 13 In the present study, we directly measured the formation kinetics of Pd(II)-5-Br-PADAP complex, which was not extracted into the heptane phase and existed only at the interface, from the spectral change in the heptane/water system.…”

Section: Introductionmentioning

confidence: 99%

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Direct Spectrophotometric Measurements of Acid-catalyzed Complexation of Palladium(II) with 2-(5-Bromo-2-pyridylazo)-5-diethylaminophenol at the Heptane/Water Interface by a Centrifugal Liquid Membrane Method

Ohashi

Watarai

2001

ANAL. SCI.

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Chemical reactions at the interfaces between two immiscible liquids have become a more interesting subject in various fields, including solvent extraction chemistry, biological chemistry and electrochemistry. 1,2 Although the interfacial complexation has been studied in some solvent extraction systems, catalytic reactions at the interface have not been reported enough compared with those in the aqueous phase. We have previously clarified the various reaction mechanisms proceeding at the liquid-liquid interface in solvent extraction systems by a highspeed stirring method 3-7 that can simultaneously measure the extraction rate of a metal complex and the interfacial concentration of a ligand or the complex from the change of the absorbance in the organic phase. However, this method has one drawback: it cannot directly measure the interfacial species. When the complex was not extracted into the organic phase and exists only at the interface, the complexation rate was indirectly determined from the consumption rate of the ligand in the organic phase in the high-speed stirring method. 6 Recently, in our laboratory we developed a new in situ spectrophotometric method, the centrifugal liquid membrane (CLM) method, to measure the species adsorbed at the liquid-liquid interface. 8,9 This method utilizes an ultra-thin two-phase liquid membrane in a rotating optical cell by a centrifugal force and can directly measure the interfacial species by transmission spectrophotometry or other spectrometries. But the previous rotating cell did not permit us to inject the sample solution rapidly while the cell was rotating. Therefore, there were some problems: fast reactions were difficult to measure and it was impossible to change the solution conditions in the course of the measurement. To solve these problems, in the present study we made a modified rotating cell that had a hole in the bottom.2-(5-Bromo-2-pyridylazo)-5-diethylaminophenol, 5-Br-PADAP or HL, has been known as a highly sensitive colorimetric reagent that forms colored complexes with various metal ions and has been used to detect trace amounts of various metal elements. [10][11][12] It was reported that 5-Br-PADAP formed a complex with Pd(II) with the mole ratio of 1:1. 13In the present study, we directly measured the formation kinetics of Pd(II)-5-Br-PADAP complex, which was not extracted into the heptane phase and existed only at the interface, from the spectral change in the heptane/water system. We clarified the kinetic mechanism of the catalytic effect of acid on the complexation reaction. Also, the advantage of the modified centrifugal liquid membrane cell in the kinetic study was demonstrated. ExperimentalReagents 5-Br-PADAP (Dojindo Lab.) was used as purchased and was dissolved in purified heptane. For the purification, heptane (G. R., Katayama Chemical) was stirred with concentrated sulfuric acid for one day (repeated three times), washed successively with distilled water and 5% sodium hydroxide aqueous solution, dehydrated by calcium chloride dehydrate overni...

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Section: Introductionmentioning

confidence: 99%

“…[10][11][12] It was reported that 5-Br-PADAP formed a complex with Pd(II) with the mole ratio of 1:1.…”

mentioning

confidence: 99%

Direct Spectrophotometric Measurements of Acid-catalyzed Complexation of Palladium(II) with 2-(5-Bromo-2-pyridylazo)-5-diethylaminophenol at the Heptane/Water Interface by a Centrifugal Liquid Membrane Method

Ohashi

Watarai

2001

ANAL. SCI.

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Simultaneous Electrochemical Detection of Co(II) and Cu(II) by 1‐Diazo‐2‐Naphthol‐4‐Sulfonic Acid/MWCNTs Modified Electrode

et al. 2017

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This work describes a simple preparation of 1‐diazo‐2‐naphthol‐4‐sulfonic acid (1,2,4‐acid) and multiwalled carbon nanotubes (MWCNTs) modified glassy carbon electrode (GCE) for the simultaneous detection of Co(II) and Cu(II). MWCNTs, with their good conductivity and large surface area, were drop‐casted onto the surface of the GCE prior to the electrodeposition of 1,2,4‐acid, a metal chelating agent. Co(II) and Cu(II) were simultaneously measured by differential pulse anodic stripping voltammetry (DPASV) in a batch system. Under optimum conditions, the linear range of Co(II) was between 0.10 and 2.5 μg mL−1 with an LOD of 80 ng mL−1. Two linear ranges were obtained for Cu(II), 0.0050 to 0.030 μg mL−1 and 0.040 to 0.25 μg mL−1,with an LOD of 2.4 ng mL−1. The method offered a high operational stability for up to 52 measurements (RSD=3.4 % for Co(II) and 2.6 % for Cu(II)) and good reproducibility (RSD=1.2 % for Co(II) and 1.7 % for Cu(II)). In the simultaneous detection of Co(II) and Cu(II), there was no effect from common interferences found in wastewater. The method was successfully applied in real water samples with good recoveries (88.2±0.8 to 102.0±0.8 % for Co(II) and 96.5±0.4 to 103.8±0.9 % for Cu(II)) and the results were in good agreement with those obtained from inductively coupled plasma optical emission spectrometry (ICP‐OES) (P>0.05).

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Determination of metal ions by capillary electrophoresis

1997

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The increasing use of capillary electrophoresis (CE) in all areas of analytical chemistry has been reflected in the appearance since 1990 of significant numbers of fundamental studies and applications of CE in the area of separations of metal ions. In this article all aspects of separations of metal ions by CE are reviewed and discussed, including general concepts and approaches, sample introduction, complex formation and sample stacking, separation selectivity, the role of kinetics, capillary wall chemistry, detection techniques, method validation, and applications to metal determinations in various matrices.

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Comparison of adsorptive stripping voltammetry (AdSV) and capillary zone electrophoresis (CZE) for the trace determination of selected metal ions, chelated with 2-(5′-bromo-2′-pyridylazo)-5-(diethylamino)phenol (PADAP)

Cited by 8 publications

References 9 publications

Direct Spectrophotometric Measurements of Acid-catalyzed Complexation of Palladium(II) with 2-(5-Bromo-2-pyridylazo)-5-diethylaminophenol at the Heptane/Water Interface by a Centrifugal Liquid Membrane Method

Direct Spectrophotometric Measurements of Acid-catalyzed Complexation of Palladium(II) with 2-(5-Bromo-2-pyridylazo)-5-diethylaminophenol at the Heptane/Water Interface by a Centrifugal Liquid Membrane Method

Simultaneous Electrochemical Detection of Co(II) and Cu(II) by 1‐Diazo‐2‐Naphthol‐4‐Sulfonic Acid/MWCNTs Modified Electrode

Determination of metal ions by capillary electrophoresis

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