Programming of temperature and flow rate of carrier gas in work with polycapillary columns for gas-liquid chromatography

Methods of programming temperature and flow rate of carrier gas for to reducing the time of analyte separation on polycapillary columns (PCC) are compared. As was shown, the programming of temperature is accompanied by a change of peak shape, associated with the irregular heating of PCC capillaries. The programming of carrier gas flow rate does not distort the shape of chromatography peaks and does not require long time to return the system to the starting conditions.     

Behavior of silver sulfide in the system Ag<Subscript>2</Subscript>S-Fe(NO<Subscript>3</Subscript>)<Subscript>3</Subscript>-HNO<Subscript>3</Subscript>-H<Subscript>2</Subscript>O

Behavior of silver sulfide in the system Ag₂S-Fe(NO₃)₃-HNO₃-H₂O was studied at 25, 55, and 80°C using the method of the simplex-lattice experiment design. The quantitative dependences of Ag₂S oxidation on the concentrations of the acid and Fe³⁺ were determined. The isoconcentration diagrams were obtained.     

Synthetic transformations of sesquiterpene lactones. V.* Synthesis and cytotoxicity of 13-aryl-substituted tourneforin derivatives

13-Aryl-substituted tourneforin derivatives were synthesized via the Heck reaction with aryliodides. The structure of (E)-13-(3,4-dimethoxybenzyl)-eudesma-4(5),11(13)-dien-6α,12-olide was confirmed by an XSA. A study of the cytotoxicity of the synthesized derivatives for CEM-13, MT-4, and U-937 tumor models showed promise for the modification.     

Sol-gel multicapillary columns for gas-solid chromatography

In this work, we report the method for the preparation of multicapillary columns (MCCs) for gas-solid chromatography. The porous layer adsorbent is formed on capillary walls by the hydrolysis of aluminum alkoxide in the presence of polypropylene glycol (PPG) and HCl. Porosity and selectivity of the adsorbent depend on reaction conditions and the concentration of PPG. Sol-gel MCCs are well suited for high-speed chromatographic analysis of light hydrocarbons by gas-solid chromatography. Nine-component mixtures of C1-C4 hydrocarbons are separated within 8-12 s. The efficiency of 25-30 cm long alumina sol-gel MCCs consisting of approximately 1400 capillaries of 40 microm diameter is up to 2500-3000 theoretical plates.     

Solubility of Lead Nitrate in Aqueous Solutions of Nitric Acid and Iron(III) Nitrate

Solubility of lead(II) nitrate in the system H₂O-Fe(NO₃)₃-HNO₃ was studied using the simplex-lattice method of experiment design.