scholarly journals The role of the 2,7-dinitrozo-1,8-dihydroxynaphthalene-3,6-disulfonic acid reagent in determining the thorium ion (IV)

2021 ◽  
pp. 54-58
Keyword(s):  
Organic Reagent ◽  
Disulfonic Acid ◽  
Acid Base ◽  
Amperometric Titration ◽  
Amperometric Determination ◽  
Half Wave ◽  
Acid Reagent ◽  
Background Electrolytes

The aim is to develop a method for the amperometric determination of thorium (IV) ion with 2,7-dinitroso-1,8-dihydroxynaphthalene-3,6-disulfoxyl reagent. Methods of amperometric determination of thorium by solution of 2,7-dinitrozo-1,8-dihydroxynaphthalene-3,6-disulfonic acid on different acid-base properties of background electrolytes and buffer mixtures are considered. The half-wave potential of new reagent was found by logarithmic analysis equal 0.72 V at pH 2.82, which once again indicates on the irreversibility of the process of electrooxidation of the studied organic reagent in used acid-base medias. The conditions for amperometric titration of thorium are optimized, and the influence of outside accompanying metals on the shape of curves and the results of its determination are investigated.

Some applications of polarography for investigation of equlibria in aqueous solutions of organic compounds

2009 ◽  
Vol 74 (11-12) ◽  
pp. 1777-1789 ◽  
Author(s):  
Petr Zuman
Keyword(s):  
Aqueous Solutions ◽  
Organic Compounds ◽  
Carbonyl Compounds ◽  
Limiting Current ◽  
Nitroso Compounds ◽  
Primary Amines ◽  
Acid Base ◽  
Fast Reactions ◽  
Half Wave

There are two possibilities how to follow equilibria of organic compounds established in aqueous solutions using polarography: for very fast reactions, information can be obtained from shifts of half-wave potentials. For slowly established equilibria, the changes in the limiting current are followed. In both cases variation of the half-wave potentials or limiting currents with concentration of a reactant, present in excess, is followed. The types of reactions, which had been followed in this way, are as follows: hydration–dehydration equilibria, additions of hydroxide ion to carbonyl and nitroso compounds, the role of slowly established acid–base equilibria involving C-acids; further also reactions involving the addition of ammonia, primary amines, hydroxylamine, and hydrazine to carbonyl compounds.

THE AMPEROMETRIC DETERMINATION OF GLUTATHIONE REDUCTASE ACTIVITY IN HUMAN ERYTHROCYTES

1955 ◽  
Vol 33 (3) ◽  
pp. 404-407 ◽  
Author(s):  
H. Bruce Collier ◽  
Sheila C. McRae
Keyword(s):  
Glutathione Reductase ◽  
Reduced Glutathione ◽  
Reductase Activity ◽  
Human Erythrocytes ◽  
Amperometric Titration ◽  
Amperometric Determination ◽  
Marked Inhibition ◽  
Glutathione Reductase Activity ◽  
Glucose 6 Phosphate Dehydrogenase

Glutathione reductase activity of hemolyzates of human erythrocytes was measured by an amperometric titration of the reduced glutathione that is formed from oxidized glutathione. The electron donor in the system was reduced triphosphopyridine nucleotide, produced by the glucose-6-phosphate dehydrogenase of the cells. Removal of the red-cell stromata from hemolyzates slightly increased the reductase activity. Addition of Na+, K+, or Ca++ had no effect on the enzyme. No marked inhibition was observed in the presence of phenothiazine, phenothiazone, phenylhydrazine, or p-chloromercuribenzoate.

THE AMPEROMETRIC DETERMINATION OF GLUTATHIONE REDUCTASE ACTIVITY IN HUMAN ERYTHROCYTES

1955 ◽  
Vol 33 (1) ◽  
pp. 404-407 ◽  
Author(s):  
H. Bruce Collier ◽  
Sheila C. McRae
Keyword(s):  
Glutathione Reductase ◽  
Reduced Glutathione ◽  
Reductase Activity ◽  
Human Erythrocytes ◽  
Amperometric Titration ◽  
Amperometric Determination ◽  
Marked Inhibition ◽  
Glutathione Reductase Activity ◽  
Glucose 6 Phosphate Dehydrogenase

Glutathione reductase activity of hemolyzates of human erythrocytes was measured by an amperometric titration of the reduced glutathione that is formed from oxidized glutathione. The electron donor in the system was reduced triphosphopyridine nucleotide, produced by the glucose-6-phosphate dehydrogenase of the cells. Removal of the red-cell stromata from hemolyzates slightly increased the reductase activity. Addition of Na+, K+, or Ca++ had no effect on the enzyme. No marked inhibition was observed in the presence of phenothiazine, phenothiazone, phenylhydrazine, or p-chloromercuribenzoate.

scholarly journals AMPEROMETRIC DETERMINATION OF CERIUM (III) USING 2,7-DINITROZO-1,8- DIHYDROXYNAPHTHALENE-3,6-DISULFONIC ACID SOLUTION

2020 ◽  
Vol 17 (36) ◽  
pp. 735-749
Author(s):  
Nigora QUTLIMUROTOVA ◽  
Salohiddin MAHMADOLIEV ◽  
Zulayho SMANOVA ◽  
Zuhra YAKHSHIYEVA ◽  
Zhasur TURSUNKULOV
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Negative Impact ◽  
Process Water ◽  
Disulfonic Acid ◽  
Express Method ◽  
Amperometric Determination ◽  
Cerium Content ◽  
Amperometric Method

Cerium and its compounds are widely used in the production of electronic devices and semiconductors, which is why these substances will enter the environment more often in the future. There is a need for effective express methods that can determine the trace amounts of cerium and other rare earth elements with high accuracy to control and study the possible negative impact of cerium compounds on the ecosystems. The objective of this research paper was to elaborate on an express method capable of producing accurate and reliable results on the content of cerium in wastewaters in the presence of other rare earth elements. The elaboration of the express method was carried out based on the amperometric titration method studying the effect of various buffer solutions on cerium determination. Moreover, the effect of strontium, lutetium, iron, yttrium, samarium, niobium, holmium, praseodymium, gadolinium, and erbium ions on acquisition accuracy of the cerium (III) ions in samples of process water was studied. The research results presented a method for the amperometric determination of cerium (III) applying 2,7-dinitroso-1,8-dihydroxynaphthalene-3,6-disulfonic acid on a rotating platinum disk microelectrode. The extraction-amperometric method of analysis was proposed for the analysis of process water. The optimal concentrations of background electrolytes and buffer mixtures and the voltage values, were determined; the stability constant of the complex was calculated; the lower limit of the determined cerium content was defined. No interfering influence of foreign ions on the determination of cerium (III) ions was observed. The developed method for determining cerium (III) has a simpler hardware design than the previously described method of pulsed direct current glow discharge mass spectrometry but has a higher detection limit.

A Molecular Approach to Immunoscintigraphy: A Study of the T-Antigen Conformation on the Surface of Tumors

1987 ◽  
Vol 26 (01) ◽  
pp. 1-6 ◽  
Author(s):  
S. Selvaraj ◽  
M. R. Suresh ◽  
G. McLean ◽  
D. Willans ◽  
C. Turner ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Tumor Cell ◽  
T Antigen ◽  
Human Carcinomas ◽  
Animal Tumor ◽  
Synthetic Antigens

The role of glycoconjugates in tumor cell differentiation has been well documented. We have examined the expression of the two anomers of the Thomsen-Friedenreich antigen on the surface of human, canine and murine tumor cell membranes both in vitro and in vivo. This has been accomplished through the synthesis of the disaccharide terminal residues in both a and ß configuration. Both entities were used to generate murine monoclonal antibodies which recognized the carbohydrate determinants. The determination of fine specificities of these antibodies was effected by means of cellular uptake, immunohistopathology and immunoscintigraphy. Examination of pathological specimens of human and canine tumor tissue indicated that the expressed antigen was in the β configuration. More than 89% of all human carcinomas tested expressed the antigen in the above anomeric form. The combination of synthetic antigens and monoclonal antibodies raised specifically against them provide us with invaluable tools for the study of tumor marker expression in humans and their respective animal tumor models.

On The Mechanism Of Heparin-Induced Potentiation Of Platelet Aggregation

1981 ◽  
Author(s):  
M Yamamoto ◽  
K Watanabe ◽  
Y Ando ◽  
H Iri ◽  
N Fujiyama ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Platelet Activation ◽  
Coagulation Factors ◽  
Marked Enhancement ◽  
Matrix Bound ◽  
Induced Aggregation ◽  
Aggregation Of Platelets ◽  
Plasma Heparin

It has been suggested that heparin caused potentiation of aggregation induced by ADP or epinephrine. The exact mechanism of heparin-induced platelet activation, however, remained unknown. In this paper, we have investigated the role of anti-thrombin III ( AT ) in heparin-induced platelet activation using purified AT and AT depleted plasma. When ADP or epinephrine was added to citrated PRP one minute after addition of heparin ( 1 u/ml, porcine intestinal mucosal heparin, Sigma Co. USA ), marked enhancement of platelet aggregation was observed, compared with the degree of aggregation in the absence of heparin. However, in platelet suspensions prepared in modified Tyrode’s solution, heparin exhibited no potentiating effect on platelet aggregation induced by epinephrine or ADP. Potentiation of epinephrine- or ADP-induced platelet aggregation by heparin was demonstrated when purified AT was added to platelet suspensions at a concentration of 20 μg/ml. AT depleted plasma, which was prepared by immunosorption using matrix-bound antibodies to AT, retained no AT, while determination of α1-antitrypsinα2- macroglobulin and fibrinogen in AT depleted plasma produced values which corresponded to those of the original plasma when dilution factor was taken into account. The activities of coagulation factors were also comparable to those of the original plasma. Heparin exhibited potentiating effect on ADP- or epinephrine-induced aggregation of platelets in original plasma, but no effect in AT depleted plasma. When purified AT was added back to AT depleted plasma at a concentration of 20 μg/ml, potentiation of platelet aggregation by heparin was clearly demonstrated.Our results suggest that effect of heparin on platelet aggregation is also mediated by anti-thrombin III.

COMPARISON OF VARIOUS METHODS FOR THE CHEMICAL ASSAY OF CORTICOIDS IN URINE

1955 ◽  
Vol 18 (4) ◽  
pp. 374-378
Author(s):  
Mogens Sprechler
Keyword(s):  
Calibration Curve ◽  
Periodic Acid ◽  
Reducing Power ◽  
Standard Technique ◽  
Phosphomolybdic Acid ◽  
Florisil Column ◽  
Chemical Assay ◽  
Chromatographic Procedure ◽  
Acid Reagent

SUMMARY Since 1949 about 10,000 urinary corticoid analyses have been performed routinely in our laboratory. The method used for this purpose was described in 1950 (Sprechler). We determine the corticoids which can be extracted from the urine with chloroform immediately after acidification to pH 1. The extract is washed with sodium hydroxide and water, a Girard separation is performed, and finally the reducing power of the ketonic fraction is measured by means of the phosphomolybdic acid reagent reaction. During the last few years two other chemical reactions have been used for comparison: The formaldehyde and the Porter-Silber method. After a thorough examination of the above methods a standard technique was followed. In the formaldehyde method a microdiffusion in a Conway unit was used instead of distillation of the formaldehyde following the oxidation with periodic acid. The calibration curve was corrected for loss of material by taking the standard doses of DOC through all the procedures of the method. A micromodification of the Porter-Silber method was chosen. Furthermore attempts were made to determine how specific the chromatographic procedure is in the determination of steroids in urinary extracts. For this purpose the Florisil column was used, and the technique described by Nelson & Samuels was followed. Finally we have investigated the glucuronide-bound corticoids in urine in a smaller series of objects.

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