scholarly journals Electrochemical Studies on Complexation and Speciation of Copper(II) in ppb Level with 1,10-Phenanthroline in Aqueous Media

1970 ◽  
Vol 46 (2) ◽  
pp. 219-224 ◽  
Author(s):  
N Nahar ◽  
NP Mona ◽  
MN Abser
Keyword(s):  
Stability Constant ◽  
Copper Complexes ◽  
Anodic Stripping Voltammetry ◽  
Aqueous Media ◽  
Stripping Voltammetry ◽  
Differential Pulse ◽  
Experimental Conditions ◽  
Overall Stability ◽  
The Stability ◽  
And Diffusion

Complexation and speciation of copper (II) in ppb level with 1,10-phenanthroline (L) in aqueous media have been investigated by differential pulse anodic stripping voltammetry using thin mercury film glassy carbon electrode (TMFGCE). The work was carried out at constant ionic strength of 0.01 mol dm-3 using NaNO3 at ambient temperature. The pH was kept constant at 9.12 ± 0.10 by the addition of borate buffer. Applying the concept of DeFord and Hume, the stability constants of different species of copper with 1,10-phenanthroline were calculated from the variation of peak potential and diffusion current of simple and complexed metal ions under the present experimental conditions. It was found that copper(II) form three complexes (1:1, 1:2 and 1: 3; metal : ligand) with 1,10-phenanthroline. The overall stability constant of copper complexes, MLn can be defined as βMLn= [MLn ]/[M2+][L]n in which M2+ = Cu2+ and L = 1,10-phenanthroline; n is an integer. The values of the stability constant of different copper complexes with 1,10-phenanthroline were found to be 109.33, 1015.10 and 1020.48 for CuL, CuL2 and CuL3, respectively (the overall charges were omitted for simplicity). The high values of overall stability constant indicate that the complexes are highly stable. Using the values of stability constant of copper complexes and hydrolysis constant of copper, the percentage of all possible copper species under present experimental conditions were calculated. Keywords: Electrochemical; Speciation; Complexation; Copper 1,10-phenanthroline. DOI: http://dx.doi.org/10.3329/bjsir.v46i2.8188 Bangladesh J. Sci. Ind. Res. 46(2), 219-224, 2011

scholarly journals Electrochemical Studies on Speciation of Cadmium(II) in ppb Level by Complexation with Ethylenediamine in Aqueous Media

1970 ◽  
Vol 44 (1) ◽  
pp. 1-10
Author(s):  
Nurun Nahar ◽  
Anshaya Ramim ◽  
M Nurul Abser
Keyword(s):  
Stability Constants ◽  
Anodic Stripping Voltammetry ◽  
Aqueous Media ◽  
Stripping Voltammetry ◽  
Differential Pulse ◽  
Exchange Equilibrium ◽  
Experimental Conditions ◽  
Mercury Film ◽  
Competitive Ligand Exchange ◽  
The Stability

The speciation of cadmium(II) in ppb level by complexation with ethylenediamine (EN) has been investigated by differential pulse anodic stripping voltammetry (DPASV) using thin mercury film coated glassy carbon electrode (TMFGCE). The overall work has been carried out at constant ionic strength of 0.01 mol dm-3 (NaNO3) at ambient temperature. The pH was kept constant at 8.81 ± 0.10 by the addition of borate buffer. The stability constants of different species of cadmium(II) with ethylenediamine have been calculated from the variation of peak potential and diffusion current of simple and complexed metal ions under the present experimental conditions. The logarithmic values of overall stability constants: log β1, log β2 and log β3 (βi = [CdLi]/[Cd2+][L]i where i = 1, 2 and 3) have been found to be 5.01, 8.9 and 11.1 for CdL, CdL2 and CdL3, respectively (charges were omitted for simplicity). The stability constants of cadmium complexes and hydrolysis constants of cadmium indicate that five different species of cadmium (Cd2+, CdOH+, CdL, CdL2 and CdL3) co-exist at ligand concentrations up to 5×10-4 mole dm-3 under the present experimental conditions. The results obtained by this method is applied to study the cadmium speciation in river water on the basis of competitive ligand exchange equilibrium. Key words: Speciation, Complexation, Aqueous media, DPASV, Mercury film electrode.   doi: 10.3329/bjsir.v44i1.2709 Bangladesh J. Sci. Ind. Res. 44(1), 1-10, 2009

Direct measurement of equilibrium constants for water-soluble porphyrin with copper(II) and cobalt(II) by differential pulse anodic stripping voltammetry (DPASV)

2012 ◽  
Vol 16 (02) ◽  
pp. 235-243
Author(s):  
Md. Shahajahan Kutubi ◽  
Masaaki Tabata
Keyword(s):  
Detection Limit ◽  
Metal Ions ◽  
Stability Constants ◽  
Anodic Stripping Voltammetry ◽  
Stripping Voltammetry ◽  
Differential Pulse ◽  
Water Soluble ◽  
Working Electrode ◽  
Anodic Stripping ◽  
The Stability

Because of high stability constants and slow metalation rate of porphyrins, it is difficult to determine stability constants of metalloporphyrins correctly. We propose here a new method for the determination of the stability constant of Cu(II) or Co(II) with 2,3,7,8,12,13,17,18-octabromo-5,10,15,20-tetrakis(N-methylpyridinium-4-yl)porphyrin, H2(OBTMPyP(4))4+ , by differential pulse anodic stripping voltammetry (DPASV) using a gold working electrode. The concentrations of free Cu(II) or Co(II) ion as low as 10-7–10-8 M were determined directly in equilibrium with H2(OBTMPyP(4))4+ of 10-7–10-8 M under optimum DPSAV conditions of rotating disk gold electrode, deposition of metals, stripping of metals, potential pulse amplitude and pulse width. Furthermore effects of supporting electrolytes, time for the attainment of chemical equilibrium and determination methods (standard addition and calibration curve methods) of total free metal ions were considered. Tetramethylammonium chloride, (CH3)4N+Cl-(TMAC) , showed the lowest detection limit of metals among other electrolytes such as Na2SO4 , NaNO3 , NaCl : 0.5 ppb for Cu(II) at I = 0.1 ((CH3)4N+Cl-) . The stability constants of K s defined as M2+ + P2- = MP ( M = Cu(II) and Co(II) , and H2P = H2(OBTMPyP(4))4+ ) were 1013.93 and 109.47 M-1 for Cu(II) and Co(II) , respectively, at I = 0.1 (CH3)4N+Cl-) and 25 °C. The working electrode was also electrochemically activated at higher potential affording to lower detection limit of metal ions as well as to measure cyclic voltammetry of metal ions, porphyrin and metalloporphyrin as low as 10-5 M. The values of E ap (vs. Ag/AgCl ) of Cu2+ , H2(OBTMPyP(4))4+ and Cu(OBTMPyP(4))4+ were 345, 338 and 425, respectively.

Fabrication of an electrochemical sensor based on metal–organic framework ZIF-8 for quantitation of silver ions: optimizing experimental conditions using central composite design (CCD)

2020 ◽  
Vol 12 (23) ◽  
pp. 3045-3055
Author(s):  
Farzaneh Hashemi ◽  
Ali Reza Zanganeh ◽  
Farid Naeimi ◽  
Maryam Tayebani
Keyword(s):  
Metal Organic Framework ◽  
Anodic Stripping Voltammetry ◽  
Silver Ions ◽  
Stripping Voltammetry ◽  
Differential Pulse ◽  
Carbon Paste ◽  
Experimental Conditions ◽  
Metal Organic ◽  
Central Composite ◽  
Organic Framework

ZIF-8 was synthesized and carbon paste electrodes (CPEs) modified with this metal–organic framework were utilized for quantitation of silver(i) by the differential pulse anodic stripping voltammetry (DPASV) technique.

Sign in / Sign up

Export Citation Format

Share Document