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

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.

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.

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.

SODIUM CHELATES OF ETHYLENEDIAMINETETRAACETIC ACID

1963 ◽  
Vol 41 (1) ◽  
pp. 18-20 ◽  
Author(s):  
Vladimir Palaty
Keyword(s):  
Stability Constant ◽  
Stability Constants ◽  
Ethylenediaminetetraacetic Acid ◽  
Glass Electrode ◽  
Neutral Solution ◽  
Experimental Conditions ◽  
The Stability ◽  
Sensitive Method

The stability constant of the sodium chelate of EDTA was determined by means of a sodium-sensitive glass electrode. It appears that a hydrogen chelate of the formula NaHY2− is formed in the neutral solution of EDTA, but is very unstable. The stability constants, pKNaY = −2.61 and pKNaHY = 0.03, are comparable to the value obtained by Schwarzenbach and Ackermann under different experimental conditions by a less sensitive method.

scholarly journals COMPARISON OF THREE EXTRACTION METHODS OF ALLOPURINOL IN URIC ACID HERBAL MEDICINE WITH HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY QUANTIFICATION

2021 ◽  
pp. 141-147
Author(s):  
RIMADANI PRATIWI ◽  
RASPATI D. MULYANINGSIH ◽  
NYI M. SAPTARINI
Keyword(s):  
Herbal Medicine ◽  
High Performance ◽  
Solid Phase ◽  
Extraction Methods ◽  
Liquid Extraction ◽  
Filtering Method ◽  
Liquid Liquid Extraction ◽  
Accuracy And Precision ◽  
Relative Standard ◽  
Parameters Of Accuracy

Objective: This study was aimed to understand and determine the effectiveness of allopurinol extraction in herbal medicine from three extraction methods based on parameters of accuracy and precision. Methods: The study consisted of three methods including dissolving and filtering, liquid-liquid extraction, and solid-phase extraction with mixed-mode cation exchanger (SPE-MCX). The procedures were carried out using NaOH and HCl in dissolving and filtering method; methanol, HCl, and ethyl acetate in liquid-liquid extraction; and NH4OH elution solvent in SPE-MCX. Results: The results showed that extraction effectiveness based on accuracy level was the dissolving and filtering method>SPE-MCX>liquid-liquid extraction with % recovery+SD of 91.314+2.903%, 87.533+4.950%, and 54.549+3.517%, respectively. The precision level was the dissolution and filtering method>SPE-MCX>liquid-liquid extraction based on % relative standard deviations (RSD) of 3.18%, 5.226%, and 6.446%, respectively. Conclusion: It can be concluded that the allopurinol extraction method with the highest effectiveness based on accuracy and precision parameters in herbal medicine is the dissolving and filtering method.

Thermodynamic parameters for the complexation of Tc(IV) with bromide under aqueous conditions

2020 ◽  
Vol 108 (5) ◽  
pp. 409-414
Author(s):  
Cecilia Eiroa-Lledo ◽  
Donald E. Wall ◽  
Nathalie A. Wall
Keyword(s):  
Working Conditions ◽  
Equilibrium Constants ◽  
Liquid Extraction ◽  
Complexation Reaction ◽  
Hydrolysis Constant ◽  
Carboxylate Ligands ◽  
Liquid Liquid Extraction ◽  
Varied Temperature ◽  
Aqueous Conditions ◽  
Aqueous Complexes

AbstractTechnetium-99 is a long-lived fission product present in nuclear wastes, found mainly as Tc(VII) and Tc(IV) in the environment. The quantification of the equilibrium constants for the formation of Tc(IV) aqueous complexes has been limited to carboxylate ligands and interactions with the halides is mostly unknown. This work reports equilibrium constants of the formation of the TcO(OH)+ complexes with Br−, in a 3 M NaClO4 solution of pcH 2 and varied temperature, using a liquid-liquid extraction system. Neutron activation confirmed the suitability of the extraction technique for this work. Under the working conditions, Br− forms a weak exothermic TcO(OH)Br complex, with a Gibbs free energy (ΔGr) of 3 ± 3 kJ · mol−1 at a temperature of 273.15 K. The values for ΔHr (−32 ± 3 kJ · mol−1) and ΔSr (106 ± 9 J · mol−1 · K−1) of the complexation reaction were quantified using a van’t Hoff analysis. This work also showed that bromide addition does not displace the hydroxide from TcO(OH)+, as the equilibrium constant of bromide addition is much weaker than the first hydrolysis constant of the metal.

Transferrin binding of Al3+ and Fe3+.

1987 ◽  
Vol 33 (3) ◽  
pp. 405-407 ◽  
Author(s):  
R B Martin ◽  
J Savory ◽  
S Brown ◽  
R L Bertholf ◽  
M R Wills
Keyword(s):  
Stability Constant ◽  
Blood Plasma ◽  
Stability Constants ◽  
Metal Ion ◽  
Equilibrium Dialysis ◽  
Ion Binding ◽  
Metal Ion Binding ◽  
Quantitative Studies ◽  
Intensity Changes ◽  
The Stability

Abstract An understanding of Al3+-induced diseases requires identification of the blood carrier of Al3+ to the tissues where Al3+ exerts a toxic action. Quantitative studies demonstrate that the protein transferrin (iron-free) is the strongest Al3+ binder in blood plasma. Under plasma conditions of pH 7.4 and [HCO3-]27 mmol/L, the successive stability constant values for Al3+ binding to transferrin are log K1 = 12.9 and log K2 = 12.3. When the concentration of total Al3+ in plasma is 1 mumol/L, the free Al3+ concentration permitted by transferrin is 10(-14.6) mol/L, less than that allowed by insoluble Al(OH)3, by Al(OH)2H2PO4, or by complexing with citrate. Thus transferrin is the ultimate carrier of Al3+ in the blood. We also used intensity changes produced by metal ion binding to determine the stability constants for Fe3+ binding to transferrin: log K1 = 22.7 and log K2 = 22.1. These constants agree closely with a revision of the reported values obtained by equilibrium dialysis. By comparison with Fe3+ binding, the Al3+ stability constants are weaker than expected; this suggests that the significantly smaller Al3+ ions cannot coordinate to all the transferrin donor atoms available to Fe3+.

Discontinuous spectrocolorimetric titration method for determining stability constants of fulvic acid - iron complexes

Soil Research ◽  
1997 ◽  
Vol 35 (6) ◽  
pp. 1279 ◽  
Author(s):  
S. B. Pandeya ◽  
A. K. Singh
Keyword(s):  
Stability Constant ◽  
Stability Constants ◽  
Aqueous Media ◽  
Poultry Manure ◽  
Fulvic Acids ◽  
Titration Method ◽  
Binding Ability ◽  
Press Mud ◽  
Determining Factors ◽  
The Stability

The stability constants for the complexes formed between iron species existing in ambient soil environment and fulvic acids (FA) extracted from organic wastes like sewage sludge, farm yard manure (FYM), poultry manure, and press mud were determined in aqueous media of pH 5·0 and 8·5 by discontinuous spectrocolorimetric titration method. The values of stability constant (log K) of Fe–FA complexes estimated at pH 5·0 were 6·026, 6·212, 6·270, and 6·342 for FYM, sludge, poultry manure, and press mud, respectively. The respective values at pH 8·5 were 6·145, 6·276, 6·350, and 6·940. The order of the values of log K for different preparations of fulvic acids was press mud > poultry manure > sludge > FYM. The functional group contents, their pH of neutralisation, and electrostatic properties of the FA such as pKINT, pKm, and 0·868 nW, were found to be the determining factors for maximum binding ability of FA for metal cations and the stability constant of Fe–FA for different FA preparations. The basic assumptions and the limitations of the discontinuous spectrocolorimetric estimation of stability constants for Fe–FA are discussed.

Quantitation and Confirmation of Chloramphenicol, Florfenicol, and Nitrofuran Metabolites in Honey Using LC-MS/MS

2018 ◽  
Vol 101 (3) ◽  
pp. 897-903 ◽  
Author(s):  
Brian T Veach ◽  
Renea Anglin ◽  
Thilak K Mudalige ◽  
Paula J Barnes
Keyword(s):  
Extraction Procedure ◽  
Extraction Methods ◽  
Liquid Extraction ◽  
Tandem Ms ◽  
Robust Method ◽  
Calibration Standards ◽  
Single Extraction ◽  
Liquid Liquid Extraction ◽  
Lc Tandem Ms ◽  
Nitrofuran Metabolites

Abstract This paper describes a rapid and robust method utilizing a single liquid–liquid extraction for the quantitation and confirmation of chloramphenicol, florfenicol, and nitrofuran metabolites in honey. This methodology combines two previous extraction methods into a single extraction procedure and utilizes matrix-matched calibration standards and stable isotopically labeled standards to improve quantitation. The combined extraction procedure reduces the average extraction time by >50% when compared with previously used procedures. The drug residues were determined using two separate LC-tandem MS conditions. Validation of all the analytes was performed, with average quantitation ranging from 92 to 105% for all analytes and the RSDs for all analytes being ≤12%.

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