The adsorption of methyl red at the dropping mercury electrode

1970 ◽  
Vol 23 (1) ◽  
pp. 43 ◽  
Author(s):  
KG Boto ◽  
FG Thomas
Keyword(s):  
Sodium Nitrate ◽  
Supporting Electrolyte ◽  
Mercury Electrode ◽  
Methyl Red ◽  
Surface Excess ◽  
Solution Interface ◽  
Dropping Mercury Electrode

Surface excess concentrations of methyl red at the mercury-solution interface have been determined at pH 7.00, 9.80, and 12.30 from electrocapillary measurements using 0.lM sodium nitrate as supporting electrolyte. The results are interpreted in terms of a reorientation of the methyl red anion between -0.4 V and -0.6 V (v. S.C.E.)

Studies of a Mixed Adsorption Layer of Butan-1-ol and o-Toluidine on Mercury Electrode

2002 ◽  
Vol 67 (11) ◽  
pp. 1579-1588 ◽  
Author(s):  
Dorota Sieńko ◽  
Dorota Gugała ◽  
Jolanta Nieszporek ◽  
Joanna Jankowska ◽  
Jadwiga Saba
Keyword(s):  
Thermodynamic Analysis ◽  
Adsorption Layer ◽  
Supporting Electrolyte ◽  
Mercury Electrode ◽  
Interaction Constant ◽  
Repulsive Interaction ◽  
Surface Excess ◽  
Adsorption Parameters ◽  
Frumkin Isotherm ◽  
Adsorption Layers

The results of thermodynamic analysis of o-toluidine adsorption on a mercury electrode in the presence of various butan-1-ol amounts complete our previous studies on properties of mixed adsorption layers of toluidine isomers-butan-1-ol. The values of the relative surface excess Γ'°T obtained for o-toluidine show that adsorption of this compound decreases with increasing of butan-1-ol concentration. Analysis of adsorption parameters derived from the Frumkin isotherm indicates that in the presence of 0.33 M BuOH in 1 M NaClO4 with adjusted pH 3 as supporting electrolyte, ∆G0 values for o-toluidine are the highest and, at the same time, the strongest repulsive interaction occurs. In the presence of 0.11 M butan-1-ol, smaller values of ∆G0 for o-toluidine correspond to weaker repulsive interaction. Therefore the change of the Γ'°T value for o-toluidine as a function of butan-1-ol concentration is the result of mutual changes of ∆G0 and interaction constant A between adsorbate molecules.

Polarography of nickel in concentrated chloride media

1966 ◽  
Vol 19 (8) ◽  
pp. 1343 ◽  
Author(s):  
TM Florence
Keyword(s):  
Ionic Strength ◽  
Graphite Electrode ◽  
Supporting Electrolyte ◽  
Anhydrous Methanol ◽  
Pyrolytic Graphite ◽  
Hydration Number ◽  
Mercury Electrode ◽  
Specific Adsorption ◽  
Dropping Mercury Electrode ◽  
Pyrolytic Graphite Electrode

In concentrated chloride media, nickel is reduced at far more positive potentials than in dilute solutions. The positive shift in half-wave potential increases as the ionic strength is raised, and is also greater when the cation of the supporting electrolyte has a high hydration number. Evidence is presented to show that the reduction in overpotential is due to the formation of a nickel chloride complex, [Ni(H2O)5Cl]+, which has a stoicheiometric stability constant of 0.094 � 0.009 at an ionic strength of 10.0. Spectrophotometric results show that this nickel species is not formed in low ionic strength solutions. In anhydrous methanol saturated with lithium chloride, nickel is present as the tetrachloro complex, [NiCl,]2-, which has similar polarographic behaviour to the monochloro complex. Current-potential curves recorded at a rotated pyrolytic graphite electrode enabled the behaviour of nickel to be studied in the absence of specific adsorption of the chloride ion. Nickel is reduced at more positive potentials at a dropping mercury electrode than at the pyrolytic graphite electrode, and the results indicate that this difference is due to specific adsorption of chloride on the mercury electrode.

Analysis of the Electrode Kinetics of Ni(II) Reduction in Thiocyanate Media on the Dropping Mercury Electrode

2000 ◽  
Vol 65 (3) ◽  
pp. 326-342
Author(s):  
María S. Crespo-Pinilla ◽  
Fernando Mata-Pérez ◽  
Rosa M. Villamañán
Keyword(s):  
Ionic Strength ◽  
Compensation Effect ◽  
Supporting Electrolyte ◽  
Mercury Electrode ◽  
Electrode Kinetics ◽  
Surface Process ◽  
Experimental Conditions ◽  
Dropping Mercury Electrode ◽  
Kinetics Of

A study of two prewaves of the Ni(II)-SCN- system was carried out under the experimental conditions when the influence of electroreduction of SCN- is negligible. Kinetics of Ni(II) reduction in thiocyanate media on the dropping mercury electrode was studied by DC Tast Polarography (DCTP) via determination of Koutecký's parameter χ; the influence of different variables was analyzed. The study of prewaves was performed using various polarographic techniques. Values of χ depend on the SCN- concentration, pH, ionic strength (Ψ-effect) and on the nature of the supporting electrolyte. The number of electrons n, the transfer coefficient α, the stoichiometric number ν, ∆H≠, and ∆S≠ were determined (compensation effect). The first prewave has character of a reaction in the solution, the second prewave is a surface process. Main features of both mechanisms are common: catalytic nature, one-electron step discharge and the rate-determining process between species of opposite charges.

Polarography of some coordination compounds of platinum. IV. Compounds of platinum(II) containing 1,10-Phenanthroline

1956 ◽  
Vol 9 (2) ◽  
pp. 143 ◽  
Author(s):  
JR Hall ◽  
RA Plowman
Keyword(s):  
Coordination Compounds ◽  
Supporting Electrolyte ◽  
Mercury Electrode ◽  
The Other ◽  
Ion Concentration ◽  
Metallic Platinum ◽  
Dropping Mercury Electrode ◽  
Adsorption Phenomena ◽  
Complex Ion

Four ions were studied at the dropping mercury electrode. They were [Pt(ophen)2]2+, [Pt(ophen)(en)]2+, [Pt(ophen)(py)2]2+, and [Pt(ophen)(py)Cl]+, where ophen= 1,10- phenanthroline, en=ethylenediamine, and py=pyridine. The shapes of the c-v curves of the ions in supporting electrolyte 0.1M KCl, were dependent on complex ion concentration. Adsorption phenomena occurred with some ions but the effects decreased as the complex ion concentration decreased. The reduction of [Pt(ophen)2]2+ produced evidence for compounds of platinum with valency less than two. Reduction of the other ions appeared to proceed directly to metallic platinum.

Measurement of surface excess at a dropping mercury electrode by normal pulse polarography with coulometry

1981 ◽  
Vol 53 (7) ◽  
pp. 1118-1120
Author(s):  
William T. Bresnahan ◽  
Philip J. Elving
Keyword(s):  
Mercury Electrode ◽  
Surface Excess ◽  
Pulse Polarography ◽  
Dropping Mercury Electrode

POLAROGRAPHIC DETERMINATION OF THE GAMMA ISOMER OF BENZENEHEXACHLORIDE IN INSECTICIDES AND SOIL

1949 ◽  
Vol 27f (9) ◽  
pp. 368-371
Author(s):  
H. Grass ◽  
E. Y. Spencer
Keyword(s):  
Potassium Iodide ◽  
Supporting Electrolyte ◽  
Mercury Electrode ◽  
Polarographic Determination ◽  
Simple Method ◽  
Dropping Mercury Electrode

A precise and simple method for the determination of the gamma isomer of benzenehexachloride in commercial insecticides and soil by the dropping mercury electrode is outlined. A satisfactory supporting electrolyte consisted of 1% potassium iodide and a trace of gelatin in 50% ethanol.

Analysis of the electrode kinetics of Ni(II) reduction at the DME in the presence of nicotine

2000 ◽  
Vol 78 (5) ◽  
pp. 521-526 ◽  
Author(s):  
M S Crespo-Pinilla ◽  
A B Infante ◽  
F Mata-Pérez
Keyword(s):  
Surface Reaction ◽  
Supporting Electrolyte ◽  
Mercury Electrode ◽  
Electrode Kinetics ◽  
Experimental Conditions ◽  
Opposite Charge ◽  
Nicotine Concentration ◽  
Dropping Mercury Electrode ◽  
Kinetics Of

A study of the prewave of the Ni2+ - nicotine system was carried out under the experimental conditions when the influence of electroreduction of nicotine is negligible. The kinetics of Ni(II) reduction in nicotine media on the dropping mercury electrode were studied by direct current Tast polarography (DCTP) via the determination of the Koutecky's parameter, χ and the influence of different variables was analyzed. An electrochemical study of the prewave was also made by using various polarographic techniques. Values of χ depend on the nicotine concentration, pH, ionic strength (ψ-effect), and on the nature of the supporting electrolyte. The αn product (χ = transfer coefficient, n = number of electrons) and the stoichometric number,v, were determined. The prewave is interpreted as a surface reaction, the main features of the mechanism being its catalytic nature. The discharge is a two electron step and reaction between species of opposite charge is rate-determining.Key words: catalytic, prewave, polarography, nickel(II), nicotine.

Polarography of some coordination compounds of Platinum. III. Ions of the tetrammineplatinum(II) type

1956 ◽  
Vol 9 (1) ◽  
pp. 14 ◽  
Author(s):  
JR Hall ◽  
RA Plowman
Keyword(s):  
Trans Isomer ◽  
Coordination Compounds ◽  
Supporting Electrolyte ◽  
Mercury Electrode ◽  
Trans Isomers ◽  
Cis And Trans Isomers ◽  
Current Voltage ◽  
Dropping Mercury Electrode ◽  
Divalent Platinum ◽  
Cis And Trans

A number of tetrammine ions of divalent platinum, in which the ligands were ammonia, methylamine, dimethylamine, ethylenediamine, pyridine, aniline, and combinations of some of these, were studied at the dropping mercury electrode. Some of the ions showed maxima in their current-voltage curves (c-v curves). The formation of hydrogen interfered with the c-v curves of other ions, so that limiting currents were not obtainable. A method was devised for the measurement of a voltage by means of which the ease of reduction of the ions could be compared. Using a supporting electrolyte of 0.1M KCl and 0.01% gelatin, the order of increasing ease of reduction was found to be [Pt{(CH3)2NH)4]2+ = [Pt(NH3)4]2+ = [Pt(NH3)3(C5H5N)]2+ = [Pt{C2H4(NH2)2}2]2+ < cis-[Pt(NH3)2(C5H5N)2]2+ < trans-[Pt(NH3)2C5H5N)2]2+ < [Pt(CH3NH2)4]2+ = [Pt(NH3)(C5H5N)3]2+ <[Pt(C6H5N)4]2+ < cis-[Pt(NH3)2(C6H5NH2)2]2+ < trans-[Pt(NH3)2(C6H5NH2)2]2+. When the ammonia groups of [Pt(NHS),l2+ were successively replaced by pyridine groups, the resulting e-v curves shifted progressively to more positive voltages. It was also found that cis- and trans-isomers of [PtA,B,I2+ reduced at different voltages. The trans-isomer reduced more readily.

scholarly journals DEVELOPING METHOD OF DIFFERENTIAL PULSE POLAROGRAPHIC FOR ANALYSIS OF CHLORAMPHENICOL RESIDUE IN MILK

2010 ◽  
Vol 4 (1) ◽  
pp. 43-48
Author(s):  
Daryono Hadi Tjahjono ◽  
Amir Musadad ◽  
Septy Mariana K
Keyword(s):  
Supporting Electrolyte ◽  
Mercury Electrode ◽  
Reference Electrode ◽  
Differential Pulse ◽  
Differential Pulse Polarography ◽  
Determination Limit ◽  
Buffer Solution ◽  
Quantitation Limit ◽  
Pulse Polarography ◽  
Dropping Mercury Electrode

A differential pulse polarographic method for a quantitative analysis of chloramphenicol residue in milk had been developed. Result showed that the method using dropping mercury electrode as working electrode, Ag/AgCl electrode as reference electrode, and platinum electrode as auxiliary electrode with an acetic buffer solution of pH 4.7 as supporting electrolyte had a recovery for chloramphenicol of (96.88 ± 3.17)% with a detection limit of 0,027 µg/mL, a quantitation limit of 0,089 µg/mL, and a determination limit of 0,010 µg/mL.   Keywords: differential pulse polarography, residue, chloramphenicol, milk

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