The crystallization process of gas hydrates during their formation in the presence surface-active substances (SAS) is studied. research conducted two directions – theoretical and experimental. Experimental data on rate methane surfactants have been obtained: high-molecular compounds are used basis polymeric quaternary ammonium salts containing side aliphatic radicals various lengths acyl fragme...

Treatment of aqueous zinc solutions with incremental additions of a ditopic fluorescent sensor of the Zinpyr family, based on pyridine/pyrazine-containing metal recognition units, affords a fluorescence titration curve with a sharp maximum at a sensor:Zn(2+) ratio of 0.5 (Zhang, X-a.; Hayes, D.; Smith, S. J.; Friedle, S.; Lippard, S. J. J. Am. Chem. Soc.2008, 130, 15788-15789). This fluorescenc...

A comparative study on the interaction of a benzophenanthridine alkaloid chelerythrine (CHL) with RNA triplex poly(U).poly(A)*poly(U) (hereafter U.A*U, .(dot) and *(asterisk) represent Watson-Crick and Hoogsteen base pairing respectively) and its parent duplex poly(A).poly(U) (A.U) was carried out by using a combination of various spectroscopic, viscometric and calorimetric techniques. The inte...

Three methods, one titrimetric and two spectrophotometric, using chloramine-T (CAT) and two dyes, metanil yellow and indigocarmine have been developed for the determination of atenolol (ATN) in bulk drug and in tablets. The titrimetric method (Method A) involves the oxidation of the drug by a measured excess of CAT in acid medium followed by the determination of the residual oxidant by iodometr...

The spectrophotometric iodine measurement for oxygen determination by the Winkler method is reexamined for theoretical and operational aspects. It is shown that the selection of an isobestic point for measuring the mixture of iodine and tri-iodide in the solution enhances reliability. The wavelength value of 466 nm was selected after a spectrum study. Then, performances are assessed by mean of ...

Quantifying the amount of carbon dioxide (CO2) in seawater is an essential component of ocean acidification research; however, equipment for measuring CO2 directly can be costly and involve complex, bulky apparatus. Consequently, other parameters of the carbonate system, such as pH and total alkalinity (AT), are often measured and used to calculate the partial pressure of CO2 (pCO2) in seawater...