Synthesis and characterization of modified silica gel as an intermediate in the generation of gaseous standard mixtures

A possibility of extending analytical applications of chemically modified silica gels is described. This involves their utilization for the generation of gaseous standard mixtures consisting of methyl chloride as the analyte and nitrogen as a carrier gas to be used for the calibration of the GC-FID system. N-methylmorpholine was chemically bonded to the propylsilylated surface of silica gel forming chloride of an appropriate immobilized compound which, under certain conditions, undergoes thermal decomposition yielding a single, volatile component (methyl chloride). Such a method of generating specific amounts of a standard substance can be used both for a single point calibration and for checking the accuracy of an analytical instrument in a relatively wide measurement range. It was found that 3.40±0.081 mg of methyl chloride can be generated per 1 g of the modified gel

European Constitution and National Constitution

Preface "The history of the question of alliance, integration, and unification of European states along different lines reaches far back. We only have to mention I. Kant and J. C. Bluntschli, who saw the future of Europe in establishing a union of its states based on the rule of law. It was on the grounds of freedom and republican democracy that J. Lorimer of Edinburgh envisaged the possibility of uniting European states. Much like him, Polish thinkers too, including A. Mickiewicz, B. Limanowski, and K. Kelles-Krauz, believed that Europe would unite as soon as its constituent states were driven by shared ideals of freedom and republican democracy."(...

Carbon Nanotubed Mediated Drug Delivery Approach Using Novel Antimicrobials

<p><strong>Original Conference Abstract</strong></p> <p>     The idea of employing carbon nanotubes (CNTs) as potential drug delivery vehicles is more than a decade old but a still emerging hot topic in the field. What still keep this topic so hot are not only the outstanding physical/chemical (high aspect ratio, strength, functionality...) properties of CNTs that have initially attracted scientists, but especially their potential side effects on the biological systems that left the researchers unconvinced for many years. The lack of standardized research methodology resulting in conflicting conclusions on the side effects of these unnatural/artificial materials have caused the CNTs to be highly questioned for the employment in biological applications. Consequently, the question of “whether the CNTs are really toxic” has become the most popular research problem.<br>     In the light of the conflicting literature data and the “unanswered toxicity” problems, CNT mediated cellular delivery of CNTs has been taken under investigation using novel antimicrobial agents. The recent study is not only expected to bring the novel antimicrobials into use but also to give answers on: i) the most reliable and stable methods for CNT functionalizations, ii) the most appropriate intra-cellular delivery mechanism for the drug, iii) the fate of CNTs after drug delivery, their bio-compatibility, iv) effects of different variables in the CNT properties, and, v) target based outcomes of the novel antimicrobial utilization in CNT research in comparison to the other reported active agents.<strong> </strong></p> <p> </p> <p>(The poster was awarded the "3rd Best Poster Award" at <em>Bioinnovation & ScanBalt Forum - International Conference on Molecular Biotechnology and Innovations for Healthy Life, Gdańsk | 16-18 of October 2013</em>)</p

Quartz Rod Coated with Modified Silica Gel as a Source of CO and CO2 for Standard Gaseous Mixtures

Quartz rods coated with a thin layer of chemically modified silica gel have been used for the generation of a two-component gaseous standard mixture containing carbon monoxide and carbon dioxide. A new method based on thermal decomposition of immobilized compounds chemically bonded to the surface of silica gel has been used in the generation process. The oxalic acid moiety bonded to the glycydoxypropylsilylated surface of silica gel underwent decarbonylation and decarboxylation at 300°C, yielding carbon monoxide and carbon dioxide. On-line connection of a thermal desorber with the GC/FID enabled calibration of the detector following the process of methanization of CO and CO2. The following amounts of CO and CO2 were generated per unit length of the rod: 15.1 × 10−8 Mol cm−1 (RSD = 5.71%) for CO and 34.2 × 10−8 Mol cm−1(RSD = 5.16%) for CO2

Utilization of standards generated in the process of thermal decomposition chemically modified silica gel for a single point calibration of a GC/FID system

The utilization of a multicomponent gaseous standard mixture, containing CO and CO(2) and obtained by thermal decomposition of a so-called immobilized compound, for a single point calibration of a GC/FID system are described. The generation of such a mixture takes place as a result of thermal decomposition of a sample of chemically modified silica gel placed in a heated chamber of thermal desorber coupled with the device being calibrated via a catalytic methanizer. The mean amount of the analyte librated from unit mass of the gel was 0.71 mg g(-1) (RSD = 3%) for carbon monoxide and 0.86 mg g(-1) (RSD = 3%) for carbon dioxide

Characterization of Modified Silica Gel as a Source of Ethene for Standard Gaseous Mixtures

The application of chemically modified silica gel as a source of gaseous standard mixture containing ethene as a measured component is described. The surface of silica gel was chemically modified, which resulted in the formation of N-oxide of diethylaminopropylsilylated silica gel. This compound undergoes thermal decomposition at 245°C, yielding known amounts of ethene. The process of thermal decomposition of chemically modified silica gel took place in a desorber furnace connected on-line via a four-port valve to the device being calibrated. Such a solution provides convenient calibration of a GC/FID system after direct introduction of a stream of the generated mixture onto the front of a GC. It was found that 480 ± 15 mg of ethene can be generated per 1 g of the modified gel

Calibration of the thermal desorption-gas chromatography-mass spectrometry system using standards generated in the process of thermal decomposition of chemically modified silica gel

A calibration method for the thermal desorption gas chromatographic-mass spectrometric (TD-GC-MS) determination of n-propanethiol based on a gas standard mixture generated in the process of thermal decomposition of chemically modified silica gel is proposed. The experimental results indicated that the total amount of n-propanethiol liberated from unit mass of the gel did not depend on the total mass of the gel used. A calibration curve for the TD-GC-MS system for n-propanethiol, determined for the relationship between the mass of n-propanethiol and the mass of the modified silica gel used, was found by a linear regression method and was characterized by a correlation coefficient r=0.99. This means that the amounts of liberated n-propanethiol are directly proportional to the mass of the modified gel used within the examined range of masses of silica gel samples. Consequently, the amount of the analyte (n-propanethiol) can be determined on the basis of mass of silica gel used and hence the modified silica gel can be treated as a standard of the liberated component (n-propanethiol) in this case)