Determination of organic substances with different boiling points in aqueous media by capillary gas-liquid chromatography

Abstract

543.544.45.38 T. I. Samsonova, and A. V. Genis Studies were conducted on separation of organic substances with different boiling points and polarity when simultaneously present in water by capillary gas-liquid chromatography on a Kristall 2000 m chromatograph.The effect of the column phase and temperature conditions on the separation factor and component exit time was investigated. Column temperature programming was used to reduce the component, especially heavy component, retention time. The chromatography regime was selected and a fast method was developed for determining components with different volatility in water during one analysis with suffi ciently high reproducibility and reliability of the results. It was shown that the time of the analysis decreased by more than two times with the same accuracy as with the standard methods. The method can be recommended for fast analysis of wastewaters for making a decision on the treatment method.Capillary gas-liquid chromatography is an effi cient method of determining low concentrations of organic substances. In this method, columns (capillaries) are used without any special carrier with the stationary phase applied on the inside of the capillary. This type of column ensures more effi cient separation in almost all cases than packed columns and columns with porous sorbents and allows conducting a quantitative analysis in lower concentration ranges. As a result of the studies using capillary gas chromatography, methods were developed for determining contaminants in monomers and solvents and many other organic compounds in waste and natural water [1-4]. These methods include chromatographic conditions (columns, temperature) that allow determining organic substances with different boiling points separately or groups of substances with close boiling points and polarity. At the same time, the process media of the enterprises, including the wastewaters, can contain organic contaminants that strongly differ in boiling point. In this case, several methods are used, and since the conditions of determination usually differ, the equipment must be realigned and calibrated or different chromatographs must be used. This increases the duration and cost of the analysis. For quickly obtaining information on the composition of production media, fast methods that allow obtaining the necessary information after one analysis are required. The instrument base for realization of the chromatographic method now allows expanding its possibilities, including programming of the column temperature.We will examine the possibility of using capillary gas-liquid chromatography and the new generation of gas chromatographs for simultaneously determining the content of compounds with different boiling points in water to analyze the process media of chemical fi bre plants. It ensures good separation of contaminants and suffi ciently high reproducibility, and reliability of the results.Scientifi c-Research Institute of Synthetic Fibres with Experimental Factory, Tver'.

Equilibrium Solubility, Modeling, and Extended Hildebrand Solubility Parameter Approach Analysis of 3-Amino-6-bromopyridazine in Four Cosolvent Blends and Ten Pure Solvents at T = 278.15 to 323.15 K

“…As far as drugs are concerned, development of the crystal form, purification, and final formulation are all inseparable from the dissolution of the drug. Especially, for drugs that are insoluble in water, the extremely poor water solubility will cause great obstacles to the development of the pharmaceutical form. − In general, as a cheap and clean solvent, water is listed as the preferred solvent by many pharmaceutical manufacturers, so improving the water solubility of drugs has become the primary research problem of many pharmaceutical scientists. Therefore, some common cosolvents are mixed with water to prepare different kinds of binary solvent mixtures which can effectively dissolve drugs with poor water solubility to improve the delivery efficiency of the drug in the human body. − …”