Electrokinetic chromatography with micelles, polymeric and monomeric additives with similar chemical functionality as pseudo-stationary phases.

A comparison is made of the retention properties of additives applied as positively charged pseudo-stationary phases for electrokinetic chromatography of neutral analytes. All additives have a quaternary ammonium as functional group. The polymeric additive [poly(N,N,N',N'-tetramethyl-N-trimethylenehexamethylenediammonium), Polybrene] has a concentration of 2% (w/w) in the background electrolyte (acetate, pH 5.2). Monomeric octyltrimethylammonium (OTMA) was used at a concentration below or above its critical micelle concentration (CMC) (140 mmol/l). At a concentration (259 mmol/l) above the CMC the system is that normally used for micellar electrokinetic chromatography with cationic micelles. However, even below the CMC, where OTMA is present as monomer, retention of the neutral analytes is observed as well. In all systems coating of the capillary wall with Polybrene establishes an electroosmotic flow directed towards the anode, counter-migrating to the electrophoretic movement of the additive. Based on the measurement of the mobility of the analytes (15 small, monofunctional aromatic compounds with different functional groups), their capacity factors, k(i), were determined in all systems. Low correlation of the k(i) values is observed between the particular systems, indicating their different selectivity at least for individual pairs of analytes. Based on the log k(i) values, a linear free energy relationship was applied to elucidate the main types of chemical interaction responsible for retention. As a result, cavity formation and n or pi electron interactions were found being significant for the micellar OTMA system, which agrees with findings described in the literature for other (cationic and anionic) micellar systems. For the polymeric system and for the monomeric OTMA system, the significant retention parameter is indicating n and pi electron interactions.

Comparison of separation selectivity in capillary electrokinetic chromatography using a cationic linear polymeric pseudo-stationary phase or monomeric additives of similar structure.

The retention properties in electrically driven systems with monomeric additives were compared to an electrokinetic chromatographic system with a linear, charged polymer of similar chemical structure (all additives are quaternary tetraalkyl ammonium ions). The monomeric additives were tetramethylammonium (TMA), tetraethylammonium (TEA) and dimethylpyrrolidinium (DMP), respectively, the polymeric additive was poly(diallyldimethyl)ammonium (PDADMA). The additive concentration in the background electrolyte was 2 and 4% (w/w). The retention characteristics were based on the apparent mobilities of 10 non-charged analytes with different chemical functionality, which were transported by the anodic electroosmotic flow in the dynamically coated capillary, and retained by the counter-flowing cationic additives. From these data capacity factors were derived, which ranged up to 0.8. Association constants were calculated, and were found between 10 and 170. Roughly, the association constants increased for a given analyte in the sequence TMA

[Comparative epicutaneous study on allergy to mild-fibrosing agents]. / Sravnitelno epikutanno izsledvane za alergiia kum mekofibrozirashti sredstva.

In connection with clinical observations and literature data about allergic manifestations in the oral cavity in the treatment of periodontal pockets with mild-fibrosing agents, we performed a comparative epicutaneous study on the preparations most often used in our country: Phytodont, maraslavin, zemisvet and preparation P. The method of Jadahsson and Block was used in patients with manifested periodontosis. Positive allergic tests with zemisvet and preparation P have not been established so far, whereas they were 5.71% with maraslavin and 8.57%--with phytodont. That provided grounds to recommend the fibrosing therapy in the single courses to be performed with various mild-fibrosing agents so as to reduce the possibilities of sendibilization. In the presence of data about drug allergy, the patients should be tested for allergy to the respective mild-fibrosing agents prior to the fibrosing therapy.