The biguanide concentration of polyhexamethylene biguanide hydrochloride (PHMB-HCl) was measured by non-aqueous titration with HClO4, argentometric titration, the Kjeldhal method, and colloidal titration. The summation value of non-aqueous titration and argentometric titration corresponded to two titrable nitrogens in five nitrogens per one unit of PHMB-HCl, and consisted with the result of the Kjeldhal method to the five nitrogens. The colloidal titration of PHMB-HCl at pH 2.05 was equal to that with the two nitrogens. The relative standard deviations of non-aqueous titration, argentometric titration, the Kjeldhal method, and colloidal titration were 0.50% for 8 runs, 0.13% for 7 runs, 3.61% for 6 runs, and 0.69% for 6 runs, respectively.
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http://dx.doi.org/10.2116/analsci.19.1525 | DOI Listing |
Chem Sci
June 2024
Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University Ithaca New York USA
In biopolymers such as proteins and nucleic acids, monomer sequence encodes for highly specific intra- and intermolecular interactions that direct self-assembly into complex architectures with high fidelity. This remarkable structural control translates into precise control over the properties of the biopolymer. Polymer scientists have sought to achieve similarly precise control over the structure and function of synthetic assemblies.
View Article and Find Full Text PDFPolymers (Basel)
June 2023
RISE PFI AS, Høgskoleringen 6B, 7491 Trondheim, Norway.
The characterization and quantification of functional groups in technical lignins are among the chief obstacles of the utilization of this highly abundant biopolymer. Although several techniques were developed for this purpose, there is still a need for quick, cost-efficient, and reliable quantification methods for lignin. In this paper, three sampling techniques for fourier transform infrared (FTIR) spectroscopy were assessed both qualitatively and quantitatively, delineating how these affected the resultant spectra.
View Article and Find Full Text PDFChem Res Toxicol
July 2023
Department of Chemistry, Faculty of Arts and Sciences, American University of Beirut, Riad El Solh, Beirut 1107 2020, Lebanon.
Recently, many electronic cigarettes (ECIGs) manufacturers have begun offering e-liquids, known as "nicotine salts". These salts that have started gaining big popularity among users can be formed by adding weak acid to e-liquid mixtures consisting of propylene glycol (PG), vegetable glycerin (VG), flavors, and nicotine. The latter can exist in two forms: monoprotonated (mp) and freebase (fb) based on the pH of the matrix.
View Article and Find Full Text PDFTalanta
June 2023
Department of Chemistry, University of North Bengal, Darjeeling, West Bengal, 734013, India. Electronic address:
Fast and precise identification of toxic G-series nerve agents in the solution and vapor phase is urgently needed to save human beings from unwanted wars and terrorist attacks, which is challenging to execute practically. In this article, we have designed and synthesized a sensitive and selective phthalimide-based chromo-fluorogenic sensor, DHAI, by a simple condensation process that shows ratiometric and turns on chromo-fluorogenic behavior towards Sarin gas mimic diethylchlorophosphate (DCP) in liquid and vapor phases, respectively. A colorimetric change, from yellow to colorless, is observed in the DHAI solution due to the introduction of DCP in daylight.
View Article and Find Full Text PDFAnn Pharm Fr
September 2021
Laboratory of Biochemistry and Neurosciences, Department of Biology, University Hassan 1(er), Settat, Morocco.
Two non-aqueous titrimetric and one visible spectrophotometric methods were developed and validated for the determination of valganciclovir hydrochloride (VLGH) in pure drug and tablets. The titrimetric methods were carried out by titrating the VLGH solution in glacial acetic acid with acetous perchloric acid (HClO) in the presence of mercuric acetate and the end point of this titration was being located either visually (method A) or potentiometrically (method B). The spectrophotometric method (method C) was based on the addition of p-dimethylaminobenzaldehyde (DMAB) solution to VLGH solution and the formed yellow condensation product was measured at 420nm.
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