Field test for microlevel determination of cationic surfactants in aqueous solution

1974 ◽  
Vol 46 (9) ◽  
pp. 1359-1359 ◽  
Author(s):  
Wolfgang C. Geyer
Keyword(s):  
Aqueous Solution ◽  
Field Test ◽  
Cationic Surfactants

scholarly journals Interaction of Dyes with Cationic Surfactants in Solutions: Determination of Critical Micelle Concentration

2019 ◽  
Vol 81 ◽  
pp. 27-34 ◽  
Author(s):  
Serghey Shapovalov ◽  
V. Ponomariov
Keyword(s):  
Aqueous Solution ◽  
Critical Micelle Concentration ◽  
Cationic Surfactant ◽  
Cationic Surfactants ◽  
Empirical Methods ◽  
Visible Spectroscopy ◽  
Cetylpyridinium Bromide ◽  
Sulforhodamine B ◽  
Semi Empirical

Interactions of sulforhodamine B or ethyl eosin (as the anionic dye) with cetylpyridinium bromide (as a cationic surfactant) have been investigated by visible spectroscopy in aqueous solution. The object of research is the association between an anion of dye and of cationic surfactant in aqueous solutions and its features. Computer simulation of these interactions was carried out with the use of AM1 and PM3 semi-empirical methods. A new spectrophotometric method was developed for determination of critical micelle concentration of cationic surfactants.

Application of Silica Nanoparticles in the Determination of Herbicides in Environmental Water Samples Using Liquid Chromatography-Mass Spectroscopy

2020 ◽  
Vol 16 (5) ◽  
pp. 748-756
Author(s):  
Mir Waqas Alam ◽  
Tentu Nageswara Rao ◽  
Yarasani Prashanthi ◽  
Vourse Sridhar ◽  
Adil Alshoaibi ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Liquid Chromatography ◽  
Silica Nanoparticles ◽  
Solid Phase ◽  
Silica Nanoparticle ◽  
Environmental Water ◽  
Phase Extraction ◽  
Functionalized Nanoparticles ◽  
Supporting Material

Background: Herbicides are very beneficial in the crop yield with the aid of controlling weeds within the agriculture, but several herbicides are chronic in soil. Objective: In this study, nanoparticles and the packages of synthesized novel silica nanoparticles were studied for the preconcentration of herbicides. Methods: These nanoparticles prepared by the Stöber mechanism were purified and functionalized. Nanoparticles thus prepared successfully were used as supporting material for the preconcentration of residues of herbicides in the water. Results: Preconcentration was achieved by preparing the silica-based solid-phase-extraction cartridges. Nanoparticles used for this purpose were within the range of 50-250 nm. An SPE cartridge was prepared by packing 200 mg of silica nanoparticle in the empty cartridge of diameter 5.5 cm and length 0.6 cm in between PTFE frits. Aqueous solutions of 0.1 μg/ml of herbicides were prepared separately, and 10 ml of the solution was passed through the cartridge at the rate of 0.2 ml/min. After passing 10 ml volume of the aqueous solution, residues adsorbed on the cartridge were eluted using 2 ml of acetonitrile. The eluate was injected to determine the herbicide residue adsorbed on the SPE cartridge. Conclusion: In the study, it was found that greater than 90% of the herbicide residues were trapped on silica nanoparticle-based SPE cartridge. An analytical method was developed for the simultaneous determination of these herbicides. The residues were quantified by LC-MS/MS with ESI mode.

Enzymatic colorimetry of lecithin and sphingomyelin in aqueous solution.

1983 ◽  
Vol 29 (8) ◽  
pp. 1513-1517 ◽  
Author(s):  
M W McGowan ◽  
J D Artiss ◽  
B Zak
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Amniotic Fluid ◽  
Enzymatic Reaction ◽  
Detergent Solution ◽  
Enzymatic Determination ◽  
Red Color ◽  
Hydrolysis Of ◽  
Zwitterionic Detergent

Abstract A procedure for the enzymatic determination of lecithin and sphingomyelin in aqueous solution is described. The phospholipids are first dissolved in chloroform:methanol (2:1 by vol), the solvent is evaporated, and the residue is redissolved in an aqueous zwitterionic detergent solution. The enzymatic reaction sequences of both assays involve hydrolysis of the phospholipids to produce choline, which is then oxidized to betaine, thus generating hydrogen peroxide. The hydrogen peroxide is subsequently utilized in the enzymatic coupling of 4-aminoantipyrine and sodium 2-hydroxy-3,5-dichlorobenzenesulfonate, an intensely red color being formed. The presence of a non-reacting phospholipid enhances the hydrolysis of the reacting phospholipid. Thus we added lecithin to the sphingomyelin standards and sphingomyelin to the lecithin standards. This precise procedure may be applicable to determination of lecithin and sphingomyelin in amniotic fluid.

Determination of the effective charge on muonium during its reaction in aqueous solution

1979 ◽  
Vol 6 (1-4) ◽  
pp. 409-412 ◽  
Author(s):  
Y. C. Jean ◽  
J. H. Brewer ◽  
D. G. Fleming ◽  
D. M. Garner ◽  
D. C. Walker
Keyword(s):  
Aqueous Solution ◽  
Effective Charge

Scale Evaluation and Eligibility Determination of a Field-Test Version of the Assessment, Evaluation, and Programming System Third Edition

2021 ◽  
pp. 027112142098171
Author(s):  
Michael D. Toland ◽  
Jennifer Grisham ◽  
Misti Waddell ◽  
Rebecca Crawford ◽  
David M. Dueber
Keyword(s):  
Field Test ◽  
Programming System ◽  
Eligibility Determination ◽  
Fit Statistics ◽  
Reliability Estimates ◽  
Test Version ◽  
Acceptable Model ◽  
Cutoff Scores ◽  
Area Classification

Rasch and classification analyses on a field-test version of the Assessment, Evaluation, and Programming System Test—Third Edition (AEPS-3), a curriculum-based assessment used to assess young children birth to age 6 years, were conducted. First, an evaluation of the psychometric properties of data from each developmental area of an AEPS-3 field-test version was conducted. Next, cutoff scores at 6-month age intervals were created and then the validity of the cutoff scores was evaluated. Results using Rasch modeling indicated acceptable model fit statistics with reasonable reliability estimates within each developmental area. Classification results showed cutoff scores accurately classified a high percentage of eligible children. Findings suggest that scores from a field-test version of the AEPS-3 are reliable within developmental areas. To the extent allowed by state criteria, early childhood interventionists could possibly use a new field-test version of the AEPS-3 to determine or corroborate eligibility for special education services.

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