The titanometric determination of azobenzene derivatives in mixed acetonitrile-methanol-water medium

1982 ◽  
Vol 47 (2) ◽  
pp. 495-502 ◽  
Author(s):  
Jiří Barek ◽  
Antonín Berka ◽  
Vladimír Borek
Keyword(s):  
Potentiometric Titration ◽  
Sodium Citrate ◽  
Azo Compounds ◽  
Water Medium ◽  
Optimal Conditions ◽  
Azobenzene Derivatives ◽  
Trivalent Titanium

The possibility of titanometric determination of a number of azobenzene derivatives in a mixed acetonitrile-methanol-water medium, which ensures sufficient solubility of the substances determined, was studied. Trivalent titanium in the presence of sodium citrate was found to be optimal. Conditions were found for the automatic potentiometric titration of a number of azo-compounds using this reagent.

scholarly journals Determination of thymol with micellar extraction preconcentration

2021 ◽  
Vol 21 (3) ◽  
pp. 267-273
Author(s):  
Elmira I. Tsygulyova ◽  
◽  
Sergei Yu. Doronin ◽  
Keyword(s):  
Aqueous Media ◽  
Spectrophotometric Study ◽  
Azo Compounds ◽  
Colorimetric Determination ◽  
Optimal Conditions ◽  
Color Channel ◽  
Micellar Extraction ◽  
Triton X ◽  
Extraction Preconcentration

For the efficient preconcentration of azo compounds – products of the interaction of 4-nitrophenyldiazonium with thymol, a system 4-nitroaniline (4-NA) – NO2- – Triton X-100 – NaOH – ethanol has been proposed. The optimal conditions for the formation of micellarsaturated phases of the system under study have been established: 3.10-4 M 4-NA – 3.10-4 M NO2- – 5% Triton X-100 – 2.8 M NaOH – 10 vol. % С 2Н5ОН. A spectrophotometric study of the above system has been carried out. A linear dependence was built in the coordinates A (at λ max = 552 nm) vs с(thymol), which is described by an equation of the form A = f(c), A = 26291c + 0.02; R2 = 0.997. The range of the determined contents of thymol is (2·10-6 – 4·10-5) mol/l. A technique for the colorimetric determination of thymol in aqueous media (color channel G) has been developed. The intensity of the channel G chromaticity (IG) is linearly dependent on pc(thymol) in accordance with the equation IG = 54.2pc – 267, R 2 = 0; the lower limit of the determined contents of thymol is 1.10-6 mol/l, which is two times less than in the variant of its spectrophotometric determination. The profiles of petal diagrams in the color coordinates of the RGB CMYK model have been constructed; the dependences of their area (S) and perimeter (P) on the thymol concentration have been obtained (P: y = 278x – 10.13; R 2 = 0.97; S: y = 20182x – 87649, R 2 = 0.99).

scholarly journals Azocoupling Reaction Of Cephalosporin Antibiotics With 8-Hydroxyquinoline And Its Application In The Analysis Of Medicinal Products

2020 ◽  
Vol 15 (3) ◽  
pp. 144-155
Author(s):  
O. Kostiv ◽  
O. Korkuna ◽  
M. Ornat
Keyword(s):  
Quality Control ◽  
Spectrophotometric Determination ◽  
Azo Compounds ◽  
Optimal Conditions ◽  
Medicinal Products ◽  
Final Volume ◽  
Auxiliary Substance ◽  
Cephalosporin Antibiotics ◽  
High Standards

Methods for spectrophotometric determination of cephalosporin antibiotics ceftazidime and ceftriaxone using azocoupling reactions with 8-hydroxyquinoline have been developed. Optimal conditions for the diazotization of antibiotics in hydrochloric acid (CHCl = 12 M) and subsequent azocoupling with 8-hydroxyquinoline in alkaline medium (0.16 M NaOH in the final volume) were established. The of azocopling products of violet and light red colors are formed, which are characterized by absorption maxima at 553 nm (ε553 = 6.31·103 M-1 cm-1) and 550 nm (ε550 = 1.45·104 M-1 cm-1) for ceftazidime and ceftriaxone, respectively. Stoichiometric ratios of the azo compounds components were determined using continuous variations methods and in both cases are 1:1. Sensitive methods of spectrophotometric determination of ceftazidime (LOD = 1.81∙10-6 M) and ceftriaxone (LOD = 5.92·10-7 M) have been developed. The selectivity of cephalosporin antibiotics spectrophotometric determination in the presence of auxiliary substance (sodium carbonate) has been investigated. The elaborated methods has been approved during the analyses of model solutions and the single component drug. The recommended procedure is well suited for the ceftazidime and ceftriaxone assay in medicine to assure high standards of quality control.

Spectrophotometric study of the complexation equilibria of cadmium ions with 5-bromo and 5-chloro derivatives of 2-(2-pyridylazo)-5-diethylaminophenol (BrPADAP, ClPADAP)

1983 ◽  
Vol 48 (1) ◽  
pp. 52-59 ◽  
Author(s):  
Vlastimil Kubáň ◽  
Miroslav Macka
Keyword(s):  
Equilibrium Constants ◽  
Spectrophotometric Study ◽  
Graphical Analysis ◽  
Optimal Conditions ◽  
Cadmium Ions ◽  
Brij 35 ◽  
Ethanol Medium ◽  
Triton X ◽  
Derivatives Of

The composition, optical characteristics, molar absorption coefficients and equilibrium constants of the reactions of formation of the ML and ML2 complexes of both reagents with cadmium(II) ions were determined by graphical analysis and numerical interpretation of the absorbance-pH curves by the modified SQUAD-G program. Optimal conditions were proposed for the spectrophotometric determination of Cd in 10% v/v ethanol medium in the presence of 0.1% w/v Triton X-100 or 1% w/v Brij 35. BrPADAP and ClPADAP are the most sensitive spectrophotometric reagents for the determination of cadmium(II) ions (ε = 1.28-1.44 . 105 mmol-1 cm2 at 560 nm and pH 8.0-9.5) with a high colour contrast in the reaction (Δλmax ~117 nm) and a selectivity similar to that of other N-heterocyclic azodyes (PAR, PAN, etc.).

Spectrophotometric study of the reactions of lanthanoids with bromopyrogallol red in the presence of cation active tensides

1982 ◽  
Vol 47 (2) ◽  
pp. 503-508 ◽  
Author(s):  
Irena Němcová ◽  
Pavla Plocková ◽  
Tran Hong Con
Keyword(s):  
Absorption Spectra ◽  
Photometric Determination ◽  
Spectrophotometric Study ◽  
Ternary Complexes ◽  
Optimal Conditions ◽  
Bromopyrogallol Red ◽  
Binary Complexes

The absorption spectra of the binary complexes of lanthanoids with bromopyrogallol red were measured and the formation of ternary complexes with cation active tenside, Septonex, was studied. Optimal conditions were found for the formation of these complexes and the possibility of their use in the photometric determination of lanthanoids was demonstrated on several examples.

The polarographic and voltammetric determination of 2,6-dicyano-4-nitro-2'-acetylamino-4'-diethylaminoazobenzene

1990 ◽  
Vol 55 (6) ◽  
pp. 1508-1517 ◽  
Author(s):  
Jiří Barek ◽  
Dagmar Civišová ◽  
Ashutosh Ghosh ◽  
Jiří Zima
Keyword(s):  
Azo Dye ◽  
Differential Pulse ◽  
Differential Pulse Polarography ◽  
Determination Limit ◽  
Polarographic Reduction ◽  
Hanging Mercury Drop Electrode ◽  
Optimal Conditions ◽  
Pulse Polarography ◽  
Pulse Voltammetry

The polarographic reduction of the title azo dye was studied and optimal conditions were found for its analytical utilization in the concentration range 1 . 10-6 - 1 . 10-7 mol l-1 using differential pulse polarography and 1 . 10-6 - 1 . 10-8 mol l-1 using fast scan differential pulse voltammetry or linear scan voltammetry at a hanging mercury drop electrode. When the latter technique is combined with adsorptive accumulation of the studied substance on the surface of the hanging mercury drop, the determination limit can be further decreased to 3 . 10-9 mol l-1.

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