Acid-base and optical properties of neutral red in the presence of ionic and nonionic tensides

1987 ◽  
Vol 52 (10) ◽  
pp. 2401-2411 ◽  
Author(s):  
Jitka Jurasová ◽  
Vlastimil Kubáň

Changes in the optical and acid-base characteristics of neutral red in the presence of hexadecylpyridinium bromide, hexadecyltrimethylammonium bromide, α-carbethoxypentadecyltrimethylammonium bromide (Septonex), sodium dodecyl sulphate, Triton X-100, and BRIJ 35 in submicellar and micellar concentrations were studied spectrophotometrically. The conditional dissociation constant of neutral red pKai* depends on the kind and concentration of tenside, kind and concentration of inert electrolyte, and concentration of the cationic dye. Changes in the pKai* values are described in terms of formation of ionic associates of the dye with the tenside and of the inert electrolyte ions with the tenside. The validity of equations for the dependence of pKai* on the logarithm of tenside concentration was proved experimentally over a wide region of cationic tenside concentrations. The changes in pKai* can also be partly accounted for by changes in the nature of the solvent. A titrimetric method based on the changes in the conditional dissociation constant of neutral red is suggested for the determination of tensides in aqueous solutions using photometric end point indication.

1997 ◽  
Vol 35 (7) ◽  
pp. 123-130 ◽  
Author(s):  
J. C. Liu ◽  
P. S. Chang

The solubility of chlorophenols as affected by surfactant was investigated. Three kinds of surfactant, sodium dodecyl sulfate, Triton X-100, and Brij 35, were utilized. The solubilization of chlorophenols by surfactant follows the order of 2,4,6-trichlorophenol > 2,4-dichlorophenol > 2,6-dichlorophenol > 2-chlorophenol; and the critical micelle concentration is an important index. The adsorption reactions of 2,4-dichlorophenol and 2,4,6- trichlorophenol onto hydrous montmorillonite in the presence of surfactant were examined. The presence of surfactant decreased the adsorption of chlorophenols significantly. The roles of hydrophobicity of chlorophenols in solubilization and adsorption behaviors are discussed.


1983 ◽  
Vol 48 (1) ◽  
pp. 52-59 ◽  
Author(s):  
Vlastimil Kubáň ◽  
Miroslav Macka

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.).


1982 ◽  
Vol 47 (10) ◽  
pp. 2676-2691 ◽  
Author(s):  
Miroslav Macka ◽  
Vlastimil Kubáň

The optical and acid-base characteristics of BrPADAP and ClPADAP were studied in mixed water-ethanol and water-DMF media and in 10% ethanol medium in the presence of cationic, anionic and nonionic tensides. The composition, optical characteristics, molar absorption coefficients and equilibrium constants of the ML and ML2 complexes with zinc(II) ions were found by graphical analysis and numerical interpretation of the absorbance curves by the modified SQUAD-G program. Optimal conditions were found for the spectrophotometric determination of Zn(II) in the presence of 0.1% Triton X-100 or 1% Brij 35 in alkaline media with pH = 6.5-10. BrPADAP and ClPADAP are the most sensitive reagents (ε = 1.3-1.6 . 105 mmol-1 cm2 at 557 and 560 nm, respectively) for the determination of zinc with high colour contrast of the reaction (Δλ = 104 nm) and selectivity similar to that for the other N-heterocyclic azodyes (PAN, PAR, etc.).


1990 ◽  
Vol 10 (2) ◽  
pp. 131-139
Author(s):  
Oyewole Adeyemo ◽  
E. O. Okegbile ◽  
O. O. Olorunsogo

For the development of immunological contraception, attention is being concentrated on the possibility of using a sperm membrane antigen. Boar sperm membrane was extracted with triton-X 100 and fractionated by Sephadex G-150 column chromatography. The glycosylated and nonglycosylated portions of protein peaks from the gel filtration were obtained by fractionating on concanavalin A-Sepharose and eluting the bound protein with 0.3 M methyl mannoside. A glycosylated fraction was found to induce sperm agglutinating antibodies in rabbit. The partially purified protein has a molecular weight of 30 kilodaltons, as determined by sodium dodecyl polyaccyrlamide gel electrophoresis. Further work is planned on the histochemical determination of the origin of this protein and species cross-activity of the antibody.


2014 ◽  
Vol 68 (11) ◽  
Author(s):  
Pavel Mikuška ◽  
Lukáš Bružeňák ◽  
Zbyněk Večeřa

AbstractA method for the rapid and sensitive determination of peroxyacetyl nitrate (PAN) in air based on a chemiluminescence reaction with an alkaline solution of luminol in the chemiluminescence aerosol detector is described. The PAN is chromatographically separated from nitrogen dioxide and ozone in a packed column filled with 5 % OV-1 on Chromosorb 30/60 and the eluted PAN is detected via the direct reaction with the luminol solution consisting of 0.002 mol L−1 luminol, 1 vol. % Brij-35 and 0.1 mol L−1 KOH. The limit of detection is 14.9 ng m−3 (3 ppt) of PAN. Alternatively, the PAN after separation is thermally converted to NO2 which is detected by the chemiluminescence reaction with a solution consisting of 0.002 mol L−1 luminol, 0.5 mol L−1 KOH, 0.2 mol L−1 Na2SO3, 0.1 mol L−1 KI, 0.05 mol L−1 EDTA and 0.5 vol. % triton X-100. The alternative approach affords the simultaneous determination of PAN and NO2. The limit of detection is 50 ppt of PAN and 50 ppt of NO2. The time resolution is 3 min. The method was applied to the measurement of ambient peroxyacetyl nitrate in air.


2019 ◽  
Vol 31 (4) ◽  
pp. 907-916
Author(s):  
M.C. Somasekhara Reddy ◽  
S.M. Sarvar Jahan ◽  
K. Sridevi ◽  
G.V. Subba Reddy

A natural surfactant (NS) of plant-base was obtained from the fruit pericarp of soapnuts by using a simple and economical method. The interaction of this natural surfactant with direct dye, anionic dye, Congo red (CR) was studied spectrophotometrically in sub-micellar and micelle concentration range in aqueous solution. These interactions (CR-NS) were compared with that of CR-CTAB (cationic surfactant-cetyl trimethylammonium bromide, CTAB), CR-SDS (anionic surfactant-sodium dodecyl sulphate, SDS) and CR-TX 100 (neutral surfactant - Triton X-100, TX 100) and were useful to understand the nature of natural surfactant. The mechanism of formation of complex due to interactions between Congo red and natural surfactant was suggested. This spectrophotometric method was used for the determination of critical micelle concentration (CMC), at which the formation of micelles was started. The CMC values obtained spectrophotometrically for the natural surfactant was coincided with the experimental value available in the literature. A definite change in the absorbance maxima of Congo red in the presence of natural surfactant (micelles of natural surfactant) was also observed. The change in maxima was also interpreted in terms of pH and CMC. The equilibrium constant of interaction between Congo red and natural surfactant was calculated on the theoretical model. The stability of the complexes of Congo red with different surfactants like CTAB, SDS, TX 100 and natural surfactant may be written in increasing order as: CR-TX 100 > CR-CTAB > CR-NS > CR-SDS. The biodegradable, non-toxic, inexpensive, environmental friendly, renewable natural surfactant was suggested in place of synthetic surfactants.


2010 ◽  
Vol 8 (3) ◽  
pp. 536-542 ◽  
Author(s):  
Mohammad Amjadi ◽  
Jamshid Manzoori ◽  
Javad Hassanzadeh

AbstractThe surfactant to dye binding degree (SBDB) methodology was used to determine fluvoxamine maleate and citalopram hydrobromide. Neutral red and sodium dodecyl sulfate (SDS) were used as the dye and surfactant, respectively, to form dye-surfactant aggregates. When a cationic drug is added to dye-surfactant mixture, it interacts with the surfactant and decreases the dye-surfactant binding degree. This decrease is proportional to the drug concentration. This was measured by monitoring the absorbance changes of the dye at 532 nm. Under the optimum conditions, the calibration graphs were linear over the range of 1.2–15 μg mL−1 and 1.1–15 μg mL−1 for fluvoxamine maleate and citalopram hydrobromide, respectively. The detection limits (signal to noise ratio = 3) were found to be 0.37 and 0.35 μg mL−1, for fluvoxamine maleate and citalopram hydrobromide, respectively.


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