CAPILLARY ELECTROKINETIC SEPARATION OF POLYCYCLIC AROMATIC HYDROCARBONS USING CETYLPYRIDINIUM BROMIDE

Polycyclic aromatic hydrocarbons (PAHs) including isomeric pairs were separated in capillary electrokinetic chromatography using a cationic surfactant cetylpyridinium bromide (CPBr) as additive. With addition of 2 mM CPBr into the running electrolyte, dynamic coating occurs in the capillary and EOF is reversed. Changes of electroosmotic and electrophoretic mobilities with increasing CPBr concentration were investigated. Under optimum separation conditions, running electrolyte contains 50% MeCN, 20 mM acetate, and 40 mM CPBr at pH = 4.0. Using high concentration of organic solvent, aggregation of surfactants into micelles is prevented. Significant retentions indicate solvophobic, n- and π-electron interactions between CPBr monomers and PAHs.     

Role of the Bay- and L-Regions in the Metabolic Activation and Carcinogenicity of Picene and Dibenz[ a,h ]anthracene

Early carcinogenicity tests found no evidence of activity for picene but found considerable initiating and carcinogenic activity for DBA. More recent investigation suggests that both pentacyclics are complete carcinogens when administered as single s.c. injections in NMRI mice, despite findings that picene acts as neither an initiating nor promoting agent. To investigate this contradiction, the complete carcinogenicity of both isomers was compared by s.c. injection in female Sprague-Dawley rats. The results demonstrated that 1 w mol of DBA administered three times weekly for 20 doses, induced sarcomas in all test animals by 33 weeks (100%). Similar treatment with picene did not induce sarcoma in any test animals by 37 weeks (0%). These present results agree with the earlier studies. It follows then that the metabolic activation and carcinogenicity of DBA and picene are dependent on the presence of an L-region, but are independent of the presence of a bay-region.     

Using slurries from flotational coal enrichment in the production of heat insulation on the basis of intershale clay

Heat insulation may be produced from intershale clay and slurries obtained in flotational coal enrichment, without employing traditional materials. The thermal conductivity and density of the insulation produced are 0.20 W/(m °C) and 1200 kg/m³.     

Cellular automata as models of inorganic structures self-assembly (Illustrated by uranyl selenate)

The theory of cellular automata is applied to describe the self-assembly of inorganic structures on molecular and nanoscale levels based on the example of uranyl selenates. The automaton that reproduces the structural topologies observed in these compounds is constructed, and its properties are studied. It is shown that the growth of complicated structural complexes in inorganic compounds depends on the structure of the nucleus as the initial condition of automaton’s work and, despite the topological differences of the resulting structures, the mechanisms of local interactions in these systems are identical. Under some conditions, this unity of mechanism leads to the formation of disordered structures.     

Determination of Critical Aggregation Concentration in the Poly-(vinylpyrrolidone)–Sodium Dodecyl Sulfate System by Capillary Electrophoresis

We introduce an alternative separation method, i.e., capillary electrophoresis to examine the polymer/surfactant interaction. The migration behavior of the poly-(vinylpyrrolidone)–sodium dodecyl sulfate (PVP–SDS) model system was screened under a high electrical field for seven different PVP initial concentrations. From the electrophoretic mobilities of formed polymer–surfactant species, the critical aggregation concentration (CAC) of SDS for PVP was determined. The CAC value in the present study was very well matched with the CAC values of this system reported by alternative methods. A strong interaction between polymer and SDS under CAC concentration was observed and the independence of CAC on polymer concentration was experimentally demonstrated.     

Composition of resinous ozonization products of raw benzene

The composition of the ozonization products of coal-based benzene is studied. The resinous products formed consist of a mixture of oxygen-bearing benzene hydrocarbons and aliphatic mono- and dicarboxylic acids.     

Fractionation effects of polystyrene on acylation reaction and their adhesive and corrosive properties

First, polystyrene (PS) was fractionated using solvent-precipitation methods; then the chemical modification of PS was investigated in the presence of Lewis acid [BF₃·O(C₂H₅)₂] catalyst with some anhydrides such as phthalic anhydride, glutaric anhydride, maleic anhydride, and propionic anhydride. The amount of the polyfunctional groups bonded to polymer structures changed depending on the molecular weight of the polymer, and more functional groups connected to the highest-molecular-weight fraction. The amount of the bonded functional groups was determined with the chemical analysis method. The structures of PS functionalized with anhydrides were confirmed by FTIR, ¹H NMR, and thermogravimetric studies. Their adhesion capability and corrosion resistance against metals have been investigated under various conditions. The results showed that the addition of functional groups to PS increases its adhesion capability and corrosion resistance. This increase is attributed to the quantity of the functional groups bonded to PS.     

Response to Comment on “Development of a High-Pressure Aerodynamic Lens for Focusing Large Particles (4–10 μm) into the Aerosol Time-of-Flight Mass Spectrometer”

Copyright 2015 American Association for Aerosol Research     

Processing of Soot by Controlled Sulphuric Acid and Water Condensation—Mass and Mobility Relationship

The effects of atmospheric processing on soot particle morphology were studied in the laboratory using the Differential Mobility Analyzer-Aerosol Particle Mass Analyzer (DMA-APM) and the DMA-DMA (Tandem DMA) techniques. To simulate atmospheric processing, combustion soot agglomerates were altered by sulphuric acid vapor condensation, relative humidity (RH) cycling, and evaporation of the sulphuric acid and water by heating. Primary investigated properties were particle mobility size and mass. Secondary properties, derived from these, include effective density, fractal dimension, dynamic shape factor, and the mass fraction of condensed material. A transformation of the soot particles to more compact forms occurs as sulphuric acid and water condense onto fresh soot. The particle mass increases and initially the mobility diameter decreases, indicating restructuring of the soot core, likely due to surface tension forces. For a given soot source and condensing liquid, the degree of compaction depends strongly on the mass (or volume) fraction of condensed material. For water and sulphuric acid condensing on combustion soot, a mass increase of 2–3 times is needed for a transformation to spherical particles. In the limit of spherical particles without voids, the effective density then approaches the inherent material density, the fractal dimension approaches 3 and the dynamic shape factor approaches 1. Our results indicate that under typical atmospheric conditions, soot particles will be fully transformed to spherical droplets on a time scale of several hours. It is expected that the morphology changes and addition of soluble material to soot strongly affect the optical and hygroscopic properties of soot.