Stable glass formation by a hexagonal ordered columnar mesophase of a low molar mass phthalocyanine derivative

Effluents of biological sewage treatment plants mainly contain non-biodegradable, polar, organic pollutants of biogenic and anthropogenic origin. This paper presents a substance-specific determination method for these compounds, which are partly able to reach drinking water during the soil filtration process. Tandem mass spectrometry (MS/MS) combined with softly ionizing interfaces is applied for this purpose. The behaviour of the functional groups of these pollutants - forming characteristic fragment ions under MS/MS conditions and abstracting neutral particles - is used for detection. With help from this screening process on specific functional groups it is possible to establish the presence of substance groups with similar behaviour in the aquatic environment. Additionally this analytical procedure provides information on the molar mass of the pollutants detected. In a second step the compounds characterized by the molar mass and belonging to a group of pollutants with specific functional groups can be identified using MS/MS.

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QELSS diffusion data for moderately broad molar mass distribution polymer samples compared with data from classical gradient techniques

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19891821 ◽

1989 ◽

Vol 54 (7) ◽

pp. 1821-1829

Author(s):

Bedřich Porsch ◽

Simon King ◽

Lars-Olof Sundelöf

Keyword(s):

Diffusion Coefficient ◽

Mass Distribution ◽

Molar Mass ◽

Molar Mass Distribution ◽

Diffusion Data ◽

Mass Distributions ◽

Classical Diffusion ◽

Polydisperse Polymer

The differences between the QELSS and classical diffusion coefficient of a polydisperse polymer resulting from distinct definitions of experimentally accessible average values are calculated for two assumed specific forms of molar mass distributions. Predicted deviations are compared with the experiment using NBS 706 standard polystyrene. QELSS Dz of this sample relates within 2-4% to the classical diffusion coefficient, if the Schulz-Zimm molar mass distribution is assumed to be valid. In general, differences between the height-area and QELSS diffusion coefficient of about 20% may be found for Mw/Mn ~ 2, and this value may increase above 35%, if strongly tailing molar mass distribution pertains to the sample.

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Activities of Components in the Ca2MgSi2O7-CaSiO3Molten System

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19960837 ◽

1996 ◽

Vol 61 (6) ◽

pp. 837-843

Author(s):

Ladislav Kosa ◽

Ivan Nerád ◽

Katarína Adamkovičová ◽

Jozef Strečko ◽

Ivo Proks

Keyword(s):

Gibbs Energy ◽

Molar Mass ◽

Excess Entropy ◽

Enthalpy Of Mixing ◽

Real Particle ◽

Entropy Of Mixing ◽

Energy Of Mixing ◽

Gibbs Energy Of Mixing

Activities of the components, the Gibbs energy of mixing, and the excess entropy of mixing have been calculated for the Ca2MgSi2O7-CaSiO3 system. The mole fractions of the components were calculated assuming that in the point of the formal component Ca2MgSi2O7, the molar mass of the quasi-real particle in the melt corresponds to its formula molar mass, whereas in the point of the formal component CaSiO3 the molar mass of the quasi-real particle in the melt is 8.5 times higher than as corresponds to its formula. The fact that the enthalpy of mixing is zero whereas the excess entropy of mixing is non-zero suggests that Ca2MgSi2O7-CaSiO3 melts behave as athermal solutions.

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