Complex-formation reactions of 7-(o-carboxyphenylazo)-8-hydroxyquinoline-5-sulphonic acid with copper(II) ions: An application in EDTA photometric microtitrations

1982 ◽  
Vol 47 (8) ◽  
pp. 2110-2120 ◽  
Author(s):  
Jaromíra Chýlková ◽  
Václav Říha ◽  
Stanislav Kotrlý
Keyword(s):  
Sulphonic Acid ◽  
Matrix Analysis ◽  
Molar Ratio ◽  
Ratio Method ◽  
Computer Assisted ◽  
Conditional Stability ◽  
Molar Ratio Method ◽  
Wide Ph Range ◽  
Ph Range ◽  
Conditional Stability Constants

Colour reactions of 7-(o-carboxyphenylazo)-8-hydroxyquinoline-5-sulphonic acid (OKFAZOX) with various metal ions are described. The formation of copper(II) complexes has been studied spectrophotometrically within a wide pH range by molar ratio method using computer-assisted regression matrix analysis of the absorbance sets. The following complexes have been identified, in agreement with the results of non-linear regression of continuous variation plots, as predominating species: CuLH2 within pH 1.3-2.9; CuLH within pH 3-7. Then, between pH 7 and 10, the complexes CuL and CuL2 take part in a stepwise equilibrium. Relevant conditional stability constants have been determined. A new photometric EDTA microtitration of copper(II) using OKFAZOX as indicator is proposed with the following optimum arrangement: pH about 5 (acetate buffer) and ionic strength 0.01; indicator concentration approx. 5 μmol l-1 or slightly higher; absorbance followed at 510 nm. End-point extrapolation gives precise results even within micromolar range:e.g. 2 μmol l-1 Cu2+ can be determined with a relative error less than 2%.

Study of properties of complexes of SNAZOXS and Naphthylazoxine 6S with copper(II), zinc(II) and lead(II) ions in solution by non-linear regression of spectrophotometric data

1979 ◽  
Vol 44 (7) ◽  
pp. 2032-2063 ◽  
Author(s):  
Milan Meloun ◽  
Jan Pancl
Keyword(s):  
Linear Regression ◽  
Sulphonic Acid ◽  
Matrix Analysis ◽  
Computer Assisted ◽  
Conditional Stability ◽  
Molar Ratios ◽  
Spectrophotometric Methods ◽  
Non Linear ◽  
Spectrophotometric Data ◽  
Conditional Stability Constants

Complexation equilibria of two metallochromic indicators viz. 7-(4-sulpho-1-naphthylazo)-8-hydroxyquinoline-5-sulphonic acid (SNAZOXS) and 7-(6-sulpho-2-naphthylazo)-8-hydroxyquinoline-5-sulphonic acid (Naphthylazoxine 6S) with copper(II), zinc(II), and lead(II) ions have been studied by various spectrophotometric methods in 0.1M-NaClO4 medium at 25 °C. Number of the coloured complexes in solution, their stoichiometry, and their overall and conditional stability constants have been determined by computer-assisted non-linear regression of the curves of continuous variations, the curves of molar ratios, the absorbance-pH curves, the curves of corresponding solutions, and by regression matrix analysis of the spectra. Besides the yellow complexes ML and ML2 the orange protonated forms MLH and M(LH)2 have also been determined.

scholarly journals Biological Study of Transition Metal Complexes with Adenine Ligand

Proceedings ◽  
2019 ◽  
Vol 41 (1) ◽  
pp. 77 ◽  
Author(s):  
Hamad M. I. Hasan ◽  
Aaza I. Yahiya ◽  
Safaa S. Hassan ◽  
Mabrouk M. Salama
Keyword(s):  
Metal Complexes ◽  
Molar Conductance ◽  
Molar Ratio ◽  
Biological Study ◽  
Ratio Method ◽  
Spectroscopic Techniques ◽  
Stoichiometric Ratio ◽  
Metal Contents ◽  
Molar Ratio Method

Adenine complexes were prepared with some of the first series transition metals in a stoichiometric ratio of 1: 2 (Mn+: L), where Mn+ = Mn2+, Fe3+, Co2+, Ni2+, Cu2+, Zn2+, and Cd2+ ions. The Complexes were characterized by the physicochemical and spectroscopic techniques as electric conductivity, metal contents, IR, UV–Visible, and molar conductance techniques. The stoichiometric ratios of the synthesized complexes were confirmed by using molar ratio method. The dissociation constant of adenine ligand was determined spectrophotometrically. Solvent effect on the electronic spectra of the adenine ligand was examined using solvents with different polarities. The biological activity of adenine ligand and its metal complexes were tested in vitro against some selected species of fungi and bacteria. The results showed a satisfactory spectrum against the tested organisms.

Estimation of diet in extinct raccoon dog species by the molar ratio method

2016 ◽  
Vol 98 (3) ◽  
pp. 292-299 ◽  
Author(s):  
Masakazu Asahara ◽  
Masanaru Takai
Keyword(s):  
Molar Ratio ◽  
Ratio Method ◽  
Raccoon Dog ◽  
Molar Ratio Method

scholarly journals Reversible Oxygenation of 2,4-Diaminobutanoic Acid-Co(II) Complexes

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Xiang Cheng ◽  
Yan Huang ◽  
Hui Li ◽  
Fan Yue ◽  
Hongmei Wen ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Oxygen Carrier ◽  
Molar Ratio ◽  
Ratio Method ◽  
Oxygen Carriers ◽  
Structural Detail ◽  
New Family ◽  
Molar Ratio Method ◽  
The Relationship ◽  
Insight Into

This paper introduces the structural characterization and studies on reversible oxygenation behavior of a new oxygen carrier Co(II)-2,4-diaminobutanoic acid (DABA) complex in aqueous solution. The composition of the oxygenated complex was determined by gas volumetric method, molar ratio method, and mass spectrometry, and the formula of the oxygenated complex was determined to be [Co(DABA)2O2]. In aqueous solution, the complex can continuously uptake and release dioxygen and exhibit excellent reversibility of oxygenation and deoxygenation ability. This complex can maintain 50% of its original oxygenation capacity after 30 cycles in 24 h and retain 5% of the original oxygenation capacity after more than 260 cycles after 72 h. When a ligand analogue was linked to histidine (His), the new complex exhibited as excellent reversible oxygenation property as His-Co(II) complex. Insight into the relationship between structural detail and oxygenation properties will provide valuable suggestion for a new family of oxygen carriers.

scholarly journals Screening and Purification of a Chymotrypsin Inhibitor from Entrolobium Saman Seeds

2010 ◽  
Vol 15 ◽  
pp. 19
Author(s):  
Maher Ali. Maqtari ◽  
A.B. Mohamed. Saad
Keyword(s):  
Molecular Weight ◽  
Enzyme Inhibitor ◽  
Gel Filtration ◽  
Exchange Chromatography ◽  
Molar Ratio ◽  
Apparent Dissociation Constant ◽  
Chymotrypsin Inhibitor ◽  
Ammonium Sulphate Precipitation ◽  
Wide Ph Range ◽  
Ph Range

A chymotrypsin inhibitor was isolated and purified from the seeds of Enterolobium saman  (Leguminaceae family) by extraction with 100 mM phosphate buffer, heat treatment, ammonium sulphate precipitation, ion-exchange chromatography on DEAEcellulose and filtration through Sephadex G-75. The final preparation appeared to be homogeneous by both chromatographic and electrophoretic analyses. ESCI had a molecular weight of about 17,890 and an isoelectric point of 5.8. ESCI inhibited bovine chymotrypsin at an inhibitor-enzyme molar ratio of 1:2. The inhibition mode of chymotrypsin inhibitor was competitive on bovine chymotrypsin. Investigation has been carried out on the complex formed between chymotrypsin and chymotrypsin inhibitor by physico-chemical methods. An apparent dissociation constant (Ki) of 9.05 X 10-8 M has been calculated for the complex. This enzyme-  inhibitor complex was isolated by gel filtration on Sephadex G-75 and a molecular weight of 43.000 was estimated for the complex. The inhibitor did not have any effect on other proteinases, such as papain, bromelin, elastase, α -amylase, trypsin and pepsin. The chemical modification of lysine residues indicated that –NH2  groups are not essential for the activity of ESCI toward chymotrypsin. The inhibitor was an acidic protein and was stable over a wide pH range of 2-12 and temperature range of 10o C-97o C. 

scholarly journals Synthesis, spectroscopic study of Pt (IV), Au (III), Rh(III),Co(II) and V (IV) complexes with sodium[5-(p-nitro phenyl) -/4- phenyl-1,2,4-triazole-3-dithiocarbamato hydrazide] and cytotoxicity assay on rhabdomyosarcoma cell line of heavy metals

2012 ◽  
Vol 9 (4) ◽  
pp. 668-679 ◽  
Author(s):  
Baghdad Science Journal
Keyword(s):  
Cell Line ◽  
Molar Absorptivity ◽  
Molar Ratio ◽  
Ratio Method ◽  
Ethanolic Solution ◽  
Flame Atomic Absorption ◽  
Square Planar ◽  
Vis Spectroscopy ◽  
Molar Ratio Method ◽  
Ft Ir

All the prepared metal complexes of Pt (IV), Au(III), Rh (III), Co (II) and V(IV) with new ligand sodium [5-(p-nitro phenyl)-/4-phenyl-1,2,4-triazole-3-dithiocarbamato hydrazide] (TRZ.DTC) have been synthesized and characterized in solid state by using flame atomic absorption, elemental analysis C.H.N.S, FT-IR ,UV-Vis Spectroscopy, conductivity and magnetic susceptibility measurements. The nature of the complexes formed in ethanolic solution has been studied following the molar ratio method also was studied stability constant and found to be stable in molar ratio1:1 of VL (IV) and CoL(II) while Pt(IV), Au(III) and Rh(III) complexes stable in molar ratio 1:2 as well as the molar absorptivity for these complexes were calculated. From the previous analyses, octahedral geometry was suggested for Pt (IV), Rh (III) and Co (II) complexes, square planar was suggested for Au(III) complex while V(IV) complex has a square pyramidal. Cytotoxic effect of PtL, AuL and RhL as well as ligand has been evaluated against RD cell line by using four different concentrations (500, 250, 125 & 62.5 µg/ml) respectively in three exposure times 24, 48 and 72 hrs and compared this effect with control positive Cis-Pt.

scholarly journals Spectrophotometric Determination of Selenium in Various Samples Using 5,6-Diaminouracil Hydrochloride (DAUH)

2015 ◽  
Vol 61 ◽  
pp. 128-136 ◽  
Author(s):  
Salwa Fares Rassi
Keyword(s):  
Acidic Medium ◽  
Metal Ion ◽  
Molar Absorptivity ◽  
Molar Ratio ◽  
Ratio Method ◽  
Colored Complex ◽  
Molar Ratio Method ◽  
Analytical Reagent ◽  
Color Reactions

A simple, rapid and sensitive spectrophotometric method was developed for the determination of Se (IV) using 5,6-diaminouracil hydrochloride (DAUH) as an analytical reagent. The reagent has been synthesized and characterized using IR, 1H NMR. The metal ion in aqueous medium forms yellow colored complex with DAUH showing maximum absorbance at 343 nm. Hence, analytical studies were further carried out at 343 nm. The reagent reacts with selenium in acidic medium to form yellow colored 1:1 (M:L) complex . The color reactions are instantaneous and absorbance values remain constant for one week. The composition of the Se (IV) complex with DAUH was studied by the method of job’s continuous variation and molar ratio method. Beer’s law was obeyed in the range 0.2-15.0 μg mL−1of Se (IV). The molar absorptivity and Sandell’s sensitivity of the method were found to be 0.5×10+4 L.mol-1.cm-1and 0.031μg.cm-2 respectively. Since DAUH method is more sensitive, it was applied for the determination of selenium in samples.

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