Determination of the Dissociation Constants of 5-Substituted 1H-Tetrazoles and Amino Acids by the Concentration Spectrophotometric Method: A New Approach

2017 ◽  
Vol 62 (8) ◽  
pp. 2400-2405 ◽  
Author(s):  
Tatiana Aleksandrovna Skripnikova ◽  
Svetlana Sergeevna Lysova ◽  
Yuriy Eduardovich Zevatskii
Keyword(s):  
Amino Acids ◽  
Spectrophotometric Method ◽  
Dissociation Constants ◽  
New Approach

scholarly journals Studies on complex formation between curcumin and Hg(II) ion by spectrophotometric method: A new approach to overcome peak overlap

2009 ◽  
Vol 7 (3) ◽  
pp. 388-394 ◽  
Author(s):  
Ratanasuda Waranyoupalin ◽  
Sumpun Wongnawa ◽  
Malinee Wongnawa ◽  
Chaveng Pakawatchai ◽  
Pharkphoom Panichayupakaranant ◽  
...  
Keyword(s):  
Complex Formation ◽  
Spectrophotometric Method ◽  
Equilibrium Concentration ◽  
Chloride Ions ◽  
Tetrahedral Complex ◽  
Microsoft Excel ◽  
New Approach ◽  
Peak Overlap ◽  
Linear Plot

AbstractComplex formation between curcumin and Hg(II) ion MeOH/H2O (1: 1 v/v) was investigated and monitored by the spectrophotometric method. The absorption peak of unreacted curcumin which was close and overlapped with that of the complex, was removed by calculation using Microsoft Excel, thereby, allowing determination of the stoichiometry of the complex by the mole-ratio and the Job’s continuous variation methods. Both methods indicated that a 1:1 complex of curcumin and Hg(II) was formed in solution. The formation constant of the 1:1 Hg(II) complex was obtained from two methods, the equilibrium concentration calculation and the linear plot of Benesi-Hildebrand equation, as log K = 4.44 ± 0.16 and 4.83 ± 0.02, respectively. The structure is proposed as a tetrahedral complex of Hg(II) with one curcumin and two chloride ions as ligands.

Determination of the Dissociation Constants of α-Amino Acids by the Ionophoretic Technique

1986 ◽  
Vol 267O (1) ◽  
Author(s):  
S. Singh ◽  
D. Gupta ◽  
H. L. Yadava ◽  
P. C. Yadava ◽  
R. K. P. Singh ◽  
...  
Keyword(s):  
Amino Acids ◽  
Dissociation Constants

Determination of dissociation constants of α-amino acids by ionophoretic technique

1985 ◽  
Vol 30 (1) ◽  
pp. 105-107 ◽  
Author(s):  
S. Singh ◽  
D. Gupta ◽  
M.M. Tewari ◽  
P.C. Yadava ◽  
S.R. Tripathi ◽  
...  
Keyword(s):  
Amino Acids ◽  
Dissociation Constants

scholarly journals A new approach for the determination of sunscreen levels in seawater by ultraviolet absorption spectrophotometry

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0243591
Author(s):  
Antonio Tovar-Sánchez ◽  
Erica Sparaventi ◽  
Amandine Gaudron ◽  
Araceli Rodríguez-Romero
Keyword(s):  
Marine Environment ◽  
Spectrophotometric Method ◽  
Analytical Methods ◽  
Low Cost ◽  
Sample Pretreatment ◽  
New Approach ◽  
Spectrophotometric Procedure ◽  
Marine Life ◽  
Absorption Spectrophotometry

Sunscreen is released into the marine environment and is considered toxic for marine life. The current analytical methods for the quantification of sunscreen are mostly specific to individual chemical ingredients and based on complex analytical and instrumental techniques. A simple, selective, rapid, reproducible and low-cost spectrophotometric procedure for the quantification of commercial sunscreen in seawater is described here. The method is based on the inherent properties of these cosmetics to absorb in the wavelength of 300–400 nm. The absorption at 303 nm wavelength correlates with the concentration of most commercial sunscreens. This method allows the determination of sunscreens in the range of 2.5–1500 mg L-1, it requires no sample pretreatment and offers a precision of up to 0.2%. The spectrophotometric method was applied to quantify sunscreen concentrations at an Atlantic Beach with values ranging from 10 to 96.7 mg L-1 in the unfiltered fraction and from the undetectable value to 75.7 mg L-1 in the dissolved fraction. This method is suggested as a tool for sunscreen quantifications in environmental investigations and monitoring programs.

Spectrophotometric method for the simultaneous determination of proteins and amino acids with p-benzoquinone

1993 ◽  
Vol 277 (1) ◽  
pp. 89-95 ◽  
Author(s):  
Dimas A.M. Zaia ◽  
Wagner J. Barreto ◽  
Nilson J. Santos ◽  
Asae S. Endo
Keyword(s):  
Amino Acids ◽  
Simultaneous Determination ◽  
Spectrophotometric Method

scholarly journals Methylmercury(II) sulfhydryl interactions. Potentiometric determination of the formation constants for complexation of methylmercury(II) by sulfhydryl containing amino acids and related molecules, including glutathione

1983 ◽  
Vol 61 (7) ◽  
pp. 1428-1434 ◽  
Author(s):  
Alan P. Arnold ◽  
Allan J. Canty
Keyword(s):  
Amino Acids ◽  
Dissociation Constants ◽  
Formation Constants ◽  
Low Ph ◽  
Acid Dissociation ◽  
Mercaptoacetic Acid ◽  
Cationic Complex ◽  
Acid Dissociation Constants ◽  
Mercaptosuccinic Acid

Formation constants for the interaction of methylmercury(II) with 2-mercaptoethanol, mercaptoacetic acid, O-methyl-mercaptoacetate, 2-mercaptosuccinic acid, L-cysteine, D,L-penicillamine, N-acetyl-D,L-penicillamine, glutathione, thiocholine, and 4-mercapto-N-methylpiperidine have been determined by potentiometric titration. For the equilibrium [Formula: see text], log β occurs in the range 14.60(1)–17.14(1), with the lowest value obtained for the cationic complex of thiocholine, [Formula: see text]. Acid dissociation constants for the ligands are reported. Formation constants for the addition of both one and two equivalents of MeHg(II) to L-cysteine have been determined, giving log K ca. 4.1 for the reaction[Formula: see text]occurring at low pH, and log K 8.8 for the reaction[Formula: see text]occurring at higher pH.

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