Comparative Studies on the Complex-Formation Equilibria of Mercury(II) with Acetylcysteine and Captopril

2000 ◽  
Vol 214 (1) ◽  
Author(s):  
H. Köszegi-Szalai ◽  
T.L. Paál ◽  
L. Barcza
Keyword(s):  
Complex Formation ◽  
Binding Sites ◽  
Extraction Methods ◽  
Liquid Extraction ◽  
Complex Formation Equilibria ◽  
Protonation Equilibria ◽  
Liquid Liquid Extraction ◽  
Formation Equilibria ◽  
The Stability ◽  
Extreme Stability

The complex-formation equilibria of mercury(II) with acetylcysteine and captopril have been studied by pH-metric and liquid-liquid extraction methods applying dithizone as a competitive ligand during the latter measurements. The stability constants of three differently protonated Hg(II)/ligand 1:2 complexes of extreme stability have been determined by the combination of extraction and pH-metric data.The formation of the less stabil Hg(II)-ligand 1:3 complexes with the coordination of three sulfhydrilate groups has been followed and the values of βThe differences in the Hg(II) complex formation and protonation equilibria between the two ligands and the possible binding sites in the complexes have been discussed.

Equilibrium Studies of Alkyltin(IV) Complexes with D-Glucosamine

1997 ◽  
Vol 62 (7) ◽  
pp. 1023-1028 ◽  
Author(s):  
Mohamed M. Shoukry ◽  
Samir M. El-Medani
Keyword(s):  
Complex Formation ◽  
Stability Constants ◽  
Acid Base ◽  
Complex Formation Equilibria ◽  
Equilibrium Studies ◽  
Formation Equilibria ◽  
Effects Of Temperature ◽  
The Stability

The acid-base and complex-formation equilibria involving glucosamine and its complexes with alkyltin(IV) chlorides have been studied by potentiometric technique. The results prove to a formation of 1 : 1 complex with trialkyltin(IV) and both 1 : 1 and 1 : 2 complexes with dialkyltin(IV) species. The stability constants in water were determined, the effects of temperature (from 15 to 35 °C) and ethanol (up to 88 vol.%) was studied and the speciation of the complexes was resolved.

scholarly journals Complex Formation Equilibria between Ag(I) and Thioureas in Propan-2-ol

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Domenico De Marco
Keyword(s):  
Complex Formation ◽  
Background Electrolyte ◽  
Complex Formation Equilibria ◽  
Entropy Changes ◽  
Enthalpy And Entropy Changes ◽  
Formation Equilibria ◽  
Enthalpy And Entropy ◽  
The Stability ◽  
Tetramethyl Thiourea ◽  
Stepwise Formation

The complex formation equilibria between Ag(I) and thiourea (Tu), N methyl-Thiourea (MeTu), N,N′-dimethyl-Thiourea (Me2Tu), N,N,N′,N′ Tetramethyl-Thiourea (Me4Tu), N-ethyl-Thiourea (EtTu), N,N′ diethyl-Thiourea (Et2Tu), and N,N′-Ethylen-Thiourea (EnTu) in propan-2-ol as solvent medium have been investigated by potentiometry within the temperature range 10°C–40°C and self-determined ionic medium by (AgNO3) concentration range 6.36·10-6–3.83·10-5 m·dm−3 (no background electrolyte added). The experimental results can be interpreted with the stepwise formation of tris-coordinated complexes AgLn  (n=1–3; hereafter charge is omitted). The stability constants log βn and the standard thermodynamic changes in enthalpy (ΔHn°) and entropy (ΔSn°) for overall complex formation reactions AgI+nL=AgLn (n=1–3) have been evaluated. The reactions are exothermic in nature and entropy disfavored for all the investigated ligands. The standard enthalpy and entropy changes for the stepwise reactions AgLn-1+L=AgLn have been evaluated by difference ΔΔHn°=ΔHn°-ΔHn-1° and ΔΔSn°=ΔSn°-ΔSn-1°. The stepwise enthalpy are mutually linearly related to the corresponding entropy changes with isoequilibrium temperatures Tiso=285, 305, and 363 K for n=1, 2, or 3 respectively.

Stability constant determinations for technetium (IV) complexation with selected amino carboxylate ligands in high nitrate solutions

2017 ◽  
Vol 105 (8) ◽  
Author(s):  
Trevor Omoto ◽  
Nathalie A. Wall
Keyword(s):  
Stability Constant ◽  
Stability Constants ◽  
Extraction Methods ◽  
Liquid Extraction ◽  
Carboxylate Ligands ◽  
Liquid Liquid Extraction ◽  
Nitrate Concentrations ◽  
The Stability ◽  
Nitrate Solutions

AbstractThe stability constants for Tc(IV) complexation with the ligands IDA, NTA, HEDTA, and DTPA were determined in varied nitrate concentrations using liquid-liquid extraction methods. The determined log β

Comparison of Sorption and Extraction Methods for Recovery of Trace Organics from Water

1983 ◽  
Vol 15 (6-7) ◽  
pp. 149-159 ◽  
Author(s):  
V C Blok ◽  
G P Slater ◽  
E M Giblin
Keyword(s):  
Solvent Extraction ◽  
Methylene Chloride ◽  
Extraction Methods ◽  
Liquid Extraction ◽  
Standard Mixture ◽  
Liquid Liquid Extraction ◽  
Trace Organics ◽  
Tenax Gc

Several commercially available adsorbents were compared with solvent extraction methods for their utility in recovering trace organics from water. The adsorbents examined included Amberlite XAD-2, XAD-4 and XAD-8, Ambersorb XE340 and XE348 and Tenax-GC. All were found to produce high artifact levels, even after extensive clean-up, making them unsuitable for the analysis of trace organics in water. Quantitatively, Likens-Nickerson or continuous liquid-liquid extraction with méthylene chloride gave better recoveries than the adsorbents. Qualitatively, extractive methods were preferred as they yielded much lower levels of impurities than the adsorbents. These methods of recovering trace organics were evaluated using a standard mixture of compounds added to the water at a level of 55 µg/l. Likens-Nickerson extraction gave comparable recoveries of this mixture at 55 µg/l and 11 µg/l.

Complex formation equilibria between astatine(I) and sulphur-containing chelating ligands

Polyhedron ◽  
1991 ◽  
Vol 10 (1) ◽  
pp. 11-17 ◽  
Author(s):  
R. Ludwig ◽  
S. Fischer ◽  
R. Dreyer ◽  
R. Jacobi ◽  
J. Beger
Keyword(s):  
Complex Formation ◽  
Chelating Ligands ◽  
Complex Formation Equilibria ◽  
Formation Equilibria

scholarly journals Extraction and Analysis of Tetrahydrocannabinol, A Cannabis Compound in Oral Fluid

2016 ◽  
Vol 9 (1) ◽  
pp. 30
Author(s):  
Wei Zhang ◽  
Jun Wang ◽  
Zhiyuan Mi ◽  
Jiangtao Su ◽  
Xiangyu You ◽  
...  
Keyword(s):  
Drug Testing ◽  
Oral Fluid ◽  
Solid Phase ◽  
Extraction Methods ◽  
Liquid Extraction ◽  
Phase Extraction ◽  
Advantages And Disadvantages ◽  
Liquid Liquid Extraction ◽  
The Common ◽  
Common Target

Although misuse and abuse of Cannabis is well known, the health benefits have been proved by various biomedical studies. Tetrahydrocannabinol (THC) is the major active substance in leaves of Cannabis, which is the common target for drug testing. In field drug testing, oral fluid (OF) has its unique advantages over other specimens such as blood, urine, and hair. Thus the study of THC in OF is gaining popularity in Cannabis research. In this review, extraction methods are introduced in three categories, which are Liquid-Liquid Extraction (LLE), Solid Phase Extraction (SPE), and Supercritical Fluid Extraction (SFE). Examples of application with each method will be covered. Advantages and disadvantages of these methods will be compared. In addition, methods in analysis following extraction will be briefly discussed.

Complex formation equilibria in the binary Zn2+–oxalate and In3+–oxalate systems

2003 ◽  
pp. 2698-2703 ◽  
Author(s):  
Ermanno Vasca ◽  
Diego Ferri ◽  
Carla Manfredi ◽  
Loredana Torello ◽  
Cecilia Fontanella ◽  
...  
Keyword(s):  
Complex Formation ◽  
Complex Formation Equilibria ◽  
Formation Equilibria
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