Nano-HPLC of Oligosaccharides – Method Development and Optimization

 The separation of homologous maltodextrins using methyl-, ethyl- and n-butyl esters of aminobenzoic acid and n-heptyloxyaniline by means of reversed phase nano-HPLC is presented. Fused silica capillaries packed with four different stationary phases were tested, the separation of the derivatized sugars was optimized and the separation properties of these columns were tested on the basis of the van Deemter plots. UV/VIS detection was used (285 nm for the aminobenzoic esters and 275 nm for the aniline derivatives) in combination with on-line ESI triple quadrupole mass spectrometry and off-line MALDI-TOF mass spectrometry. The choice of the stationary phase had a tremendous influence on the separation. Optimal results were obtained with an encapsulated ODS stationary phase and n-butyl aminebenzoate as label for the oligosaccharides. Malto-oligosaccharides with a degree of polymerization of up to of 25 could be resolved to baseline. On-line coupling with ESI-MS yielded additional information as a result of induced fragmentation and increased sensitivity by monitoring precursor ion. Off-line mass detection with MALDI-TOF was performed on the separated derivatized saccharides collected from nano-HPLC runs. The MALDI-TOF mass spectra confirm the ESI-MS data. Received January 25, 2001. Revision April 28, 2001.     

Morphology – Property Correlations of PP Materials by Means of Microhardness

The present work deals with the influence of crystallization temperature, cooling rate and annealing conditions on microhardness, indentation modulus and creep behaviour of ethylene/propylene (E/P) random copolymers with 4, 6 and 8 mol% ethylene as well as α- and β-spherulites in a homopolymer and an E/P random copolymer. The materials are unnucleated, the formation of β-spherulites occurs sporadically. Additionally the indentation creep behaviour of α- and β-nucleated PP is investigated. A nearly linear correlation between hardness as well as indentation modulus and crystallintity of the E/P copolymers can be proved. An increasing cooling rate leads to decreasing hardness and modulus values due to the hindered crystallization. For the investigation of the α- and β-phases different crystallization and annealing temperatures are used. Independent of these conditions, microhardness and modulus determined by indentation testing are lower for the β-phase in both materials. Increasing crystallization temperature and annealing lead to an increasing hardness and modulus in both phases. However, an effective annealing effect takes place only at short times and elevated temperatures above 100 °C. The increasing of microhardness and modulus is correlated with an increasing in lamellae thicknesses. Additionally, indentation creep experiments were carried out on nucleated materials that show the stronger creep tendency of the β-phase PP and the stronger influence of annealing on this phase.     

Studies on Composites of Nanoparti

Studies　on　Composites　of　Nanoparti...     

Polymer Electrolytes – New Opportunities for the Development of Multivalent Ion Batteries

Batteries, as highly concerned energy conversion system, have a great development prospect in various fields, especially in the field of energy powered vehicles. Multivalent ion batteries are getting more attention due to their low cost, high abundance in earth crust, high capacity and safety compared with Lithium batteries. Despite above advantages, several problems still need to be solved before multivalent ion batteries achieve large-scale application, such as interfacial parasitic reaction, anode passivation, and dendrites. The replacement of liquid electrolytes with gel polymer electrolytes (GPEs) which pose high safety, high mechanical strength and simplified battery system, is an effective strategy to inhibit dendrite growth and improve electrochemical performance. This review mainly discusses the advantages and challenges of multivalent ion batteries including zinc, magnesium, calcium and aluminum batteries. Meanwhile, the major targets of this review are introducing the recent developments and making a summary of the future trends of GPEs in the multivalent ion batteries.     

Development of a natural ingredient – Natural preservative: A case study

Lately, the cosmetic and personal care market has been more and more driven toward natural ingredients by the rising consumers' awareness about personal health and safety and their will for safer cosmetics free of harmful chemicals. Preservatives are no exception to the rule: evidence or suspicion of the toxicity of certain synthetic preservatives that have been around for decades pushed the cosmetic industry forward to seek for natural alternatives, as the selection of natural preservatives already available is quite limited. Sourcing active metabolites and developing new natural ingredients are long-term procedures that are thoroughly described in the present paper, via the example of the design of a natural preservative based on the Santolina chamaecyparissus extract, and of the assessments of its preservative effectiveness.     

Re-Emerging Field of Lignocellulosic Fiber – Polymer Composites and Ionizing Radiation Technology in their Formulation

Natural cellulose-based fibers offer low cost, low density composite reinforcement with good strength and stiffness. Because of their annual renewability and biodegradability, natural fibers have materialized as environmentally-friendly alternatives to synthetic fibers in the last two decades. They are replacing synthetic materials in some traditional composites in industrial manufacturing sectors such as automotive, construction, furniture, and other consumer goods. In this work, the use of lignocellulosic fibers in green materials engineering, particularly their application as polymeric composite reinforcement and surface treatment via ionizing radiation are reviewed. Because these cellulose-based materials are intrinsically hydrophilic, they require surface modification to improve their affinity for hydrophobic polymeric matrices, which enhances the strength, durability, and service lifetime of the resulting lignocellulosic fiber-polymer composites. In spite of a long history of using chemical methods in the modification of material surfaces, including the surface of lignocellulosic fibers, recent research leans instead towards application of ionizing radiation. Ionizing radiation methods are considered superior to chemical methods, as they are viewed as clean, energy saving, and environmentally friendly. Recent applications of controlled ionizing radiation doses in the formulation of natural fiber –reinforced polymeric composites resulted in products with enhanced fiber-polymer interfacial bonding without affecting the inner structure of lignocellulosic fibers. These applications are critically reviewed in this contribution.     

Development of a high-performance liquid chromatography – Tandem mass spectrometry urinary pterinomics workflow

Pteridines have evoked considerable interest from the scientific community owing to their prominent roles in human health and disease. The availability of analytical methodologies suitable for comprehensive pteridine profiling, termed here as “pterinomics”, has been limited by inconsistent sample preparation and the exclusion of lesser studied pteridine derivatives. In response, the present study describes a new pterinomics workflow using a high-performance liquid chromatography – tandem mass spectrometry (HPLC-MS/MS) methodology for the simultaneous analysis of 15 pteridine derivatives including four structural isomers, marking the largest quantitative pteridine panel that has been studied to-date. The validated method possessed excellent sensitivity with method detection limits (0.025 μg L⁻¹ to 0.5 μg L⁻¹) that were comparable or superior to existing techniques. Spiked recovery studies demonstrated the technique was both accurate (88–112%) and precise (RSD: 0–6%). A comparative study of commonly used oxidative pretreatments, including triiodide, permanganate, and manganese dioxide, revealed that the oxidative mechanisms were inefficient, complex, and concentration dependent. Finally, 50 clinical urine specimens were examined with the new technique wherein 10 pteridine derivatives were quantified and population ranges have been given. This technique can be used to examine pteridine molecular epidemiology and biochemistry to support related research applications, and may further be readily extended to include additional pteridine derivatives and biological matrices for specific applications.     

Development of Bionic Polymers

Bionics, an artificial imitation of natural products, has always been a forever dream in the fairy tale or scientific fiction when we were childhood and children live now. However, the development of science in molecular scale makes this dream of childhood and manhood realize today. Bionics, a branch of science concerned with application the data about the functioning of biological system to the solution of engineering problems, become top-priority of science in the 21st century. However, few …     

3D Printable Geopolymer Composites Reinforced with Carbon-Based Nanomaterials – A Review

Three-dimensional (3D) geopolymer printing (3DGP) technology is a rapidly evolving digital fabrication method used in the construction industry. This technology offers significant benefits over 3D concrete printing in terms of energy saving and reduced carbon emissions, thus promoting sustainability. 3DGP technology is still evolving, and researchers are striving to develop high-performance printable materials and different methods to improve its robustness and efficiency. Carbon-based nanomaterials (CBNs) with beneficial properties have a wide range of applications in various fields, including as concrete/geopolymer systems in construction. This paper comprehensively reviews the research progress on carbon-based nanomaterials (CBNs) used to develop extrusion-based 3D geopolymer printing (3DGP) technology, including dispersion techniques, mixing methods, and the materials′ performance. The rheological, mechanical, durability, and other characteristics of these materials are also examined. Furthermore, the existing research limitations and the prospects of using 3DGP technology to produce high-quality composite mixtures are critically evaluated.     

Development of polyaniline – TiO2 nano composite films and its application in corrosion inhibition of oil pipelines

Oil and gas industries are the driving force of Oman’s economy and have a relatively diversified wealth among Gulf Cooperation Council Countries. Oil pipelines play an important role in transporting oil and gas from the wellheads to the processing facilities. Corrosion normally results in the deterioration of the pipe material with exposure to the surrounding environment and complete control of corrosion is difficult. Corrosion in oil transmission pipeline would be effectively addressed by introducing conventional corrosion control practices. Most of the conventional techniques are either less effective or too expensive in controlling the deterioration rate of the pipe materials. However, preventative measures may be taken to protect the metal surface from corrosion is a possible way to reduce corrosion. This research work aimed to develop a novel technique utilizing Polyaniline (PANI) and Titanium dioxide (TiO₂) nanocomposites to assess its corrosion inhibition effect on mild steel. TiO₂ was synthesized by sol-gel process. Polyaniline-Titanium dioxide (PANI/TiO₂) nanocomposites were coated on mild steel specimen by dip coating technique. The coated specimen was subjected to stability studies at different environmental conditions and exposure time. The stable thin film coated specimen was employed in the corrosion inhibition studies at various processing environments. The characteristics of TiO₂ nanoparticles and PANI-TiO₂ thin films were analyzed using Fourier Transform Infra-Red Spectroscopy (FTIR), Energy Dispersive X-Ray analysis (EDX) and X-Ray Diffraction (XRD) and Dynamic Light scattering (DLS). Scanning Electron Microscopy (SEM) was used to visualize the surface morphology and micro structural characteristics of the preformed thin layer. Potentio dynamic test, Atmosphere test and Wet/Dry tests were carried out to investigate the corrosion behaviour of coated and uncoated specimen. The study demonstrates that the Polyaniline – TiO₂ composite thin films fabricated using dip coating technique with minimum film thickness could be a feasible solution in controlling the corrosion in oil pipelines with good film stability, high durability, with a cost effective and environmentally friendly approach.     

Physico-Chemical Properties of Laponite®/Polyethylene-oxide Based Composites

This review aims to provide a literature overview as well as the authors’ personal account to the studies of Laponite® (Lap)/Polyethylene-oxide (PEO) based composite materials and their applications. These composites can be prepared over a wide range of their mutual concentrations, they are highly water soluble, and have many useful physico-chemical properties. To the readers’ convenience, the contents are subdivided into different sections, related with consideration of PEO properties and its solubility in water, behavior of Lap systems(structure of Lap-platelets, properties of aqueous dispersions of Lap and aging effects in them), analyzing ofproperties LAP/PEO systems, Lap platelets-PEO interactions, adsorption mechanisms, aging effects, aggregation and electrokinetic properties. The different applications of Lap/PEO composites are reviewed. These applications include Lap/PEO based electrolytes for lithium polymer batteries, electrospun nanofibers, environmental, biomedical and biotechnology engineering. Both Lap and PEO are highly biocompatible with living systems and they are non-toxic, non-yellowing, and non-inflammable. Medical applications of Lap/PEO composites in bio-sensing, tissue engineering, drug delivery, cell proliferation, and wound dressings are also discussed.     

Development of Multi-Wavelength Spectral-Correction Method

Beta-correction theory has been applied extensively for the analysis of metal complex solution1-3. Recently, we found that the beta-correction principle was very useful to the determination of metal complex's properties, for example the stepwise real absorptivity (() and stability constant (Km). The new equations were established as follows: and where Ac=((A-((A')/(1-((). The term, Ac indicated the real absorbance of complex ML( ((, ( and ( were all constants), Cligand and CM were the mola…     

Transport Properties of LiClO4–Nanodiamond Composites

Russian Journal of Electrochemistry - The transport properties of solid composite electrolytes (1 – x)LiClO4–xCND (where СND are “UDA-S” nanodispersed diamonds with a...     

Development of improving processing HNBR

The hydrogenated nitrile elastomer (HNBR) is a new rubber consisting of methylene chain, cyano groups and a small number of C=C. This elastomer is produced by selection hydrogenation reaction of the olefin segments in NBR. During reaction, only the double bond should be selectively hydrogenated without the cynao groups which are essential for retaining the oil resistant properties of NBR. Present, the capacity of HNBR in total world is about 7500t/a[1],developed and commercialized by Ba…     

Studies on Kinetics of Crystallization of PA6／UFAPR Composites

The influence of Ultrafine Full-Vulcanized Acrylate Powdered Rubber(UFAPR) on the isothermal crys-tallization kinetics and nonisothermal crystallization behavior of PA8 has been studied by means of DSC. The results show that with the introduction of a small amount of UFAPR, the crystallization rate of PA8 can be increased obviously, and the crystallization temperature range can be augmented and the crystallite size distri-bution of the crystal can be narrowed down. The change of free energy perpendicular to the crystal nucleus, which has been calculated according to the Hoffman theory, is consistent with the result of Avrami′s equa-tion. The unit surface free energy of the radial-developing crystal spherulite decreases while the crystalliza-tion rate of PA8 increases with the introduction of UFAPR. Meanwhile, it is shown by means of the polariz-ing microscope(PLM) that the crystal size drops down and the number of the crystal grains augments with the addition of UFAPR, which shows that UFAPR can function as a nucleating agent.     

Development of rapid methodologies for the isolation and quantitation of drug metabolites by differential mobility spectrometry – mass spectrometry

Clinical and forensic toxicology laboratories are inundated with thousands of samples requiring lengthy chromatographic separations prior to mass spectrometry. Here, we employ differential mobility spectrometry (DMS) interfaced to nano-electrospray ionization-mass spectrometry to provide a rapid ion filtration technique for the separation of ions in gas phase media prior to mass spectral analysis on a DMS-integrated AB SCIEX API 3000 triple-quadrupole mass spectrometer. DMS is efficient at the rapid separation of ions under ambient conditions and provides many advantages when used as an ion filtration technique in tandem with mass spectrometry (MS) and MS/MS. Our studies evaluated DMS-MS/MS as a rapid, quantitative platform for the analysis of drug metabolites isolated from urine samples. In targeted applications, five metabolites of common drugs of abuse were effectively and rapidly separated using isopropanol and ethyl acetate as transport gas modifiers, eliminating the gas chromatography or liquid chromatography-based separations commonly employed in clinical and forensic toxicology laboratories. Calibration curves were prepared for the selected drug metabolites utilizing deuterated internal standards for quantitative purposes. The feasibility of separating and quantitating drug metabolites in a rapid fashion was evaluated by compensation voltage stepping followed by multiple reaction monitoring (MRM) detection. Rapid profiling of clinical and forensic toxicology samples could help to address an urgent need within the scientific community by developing high-throughput analytical methodologies, which could reduce significant case backlogs present within these laboratories.     

Kinetic Adsorption of Cd onto Nanometer Al203/Carbon Fibre

A new nanometer material, nano-Al2O3 with carbon fibre as the carrier, was employed for the removal of Cd with low concentrations from polluted water. The characterization of the material was carried out by means of SEM and TEM. Batch adsorption and elution experiments were carried out to determine the adsorption properties of Cd on the new adsorbent. The classical Thomas model was applied to estimating the equilibrium coefficients of Cd adsorption and the saturated adsorption ability. The results show that the Thomas model is fit for describing the kinetic adsorption process, and the maximum adsorption capacity of the nanometer Al2O3/carbon is 69.29 mg/g. The resulting information also indicates that the desorption of Cd eluted with de-ionized water at a rate of 9.8 mL/min can be neglected. With the advantage of a high adsorption capacity for removing low concentration Cd, the Al2O3/carbon fibre possesses the potentiality to be an effective adsorbent for the removal of Cd from polluted water.     

Properties of Single-Component Metal–Organic Framework Crystal-Glass Composites

The formation, and subsequent structural, thermal and adsorptive properties of single-component metal–organic framework crystal-glass composites (MOF-CGCs) are investigated. A series of novel materials exhibiting chemically identical glassy and crystalline phases within the same material were produced, where crystalline ZIF-62(Zn) was incorporated within an a_gZIF-62(Zn) matrix. X-ray diffraction showed that the crystalline phase was still present after heating to above the glass transition temperature of a_gZIF-62(Zn), and interfacial compatibility between the crystalline and glassy phases was investigated using a mixed-metal (ZIF-62(Co))_0.5(a_gZIF-62(Zn))_0.5 analogue. CO₂ gas adsorption measurements showed that the CO₂ uptakes of the MOF-CGCs were between those of the crystalline and glassy phases.     

Contributions to Forming and Analytical Investigations of Solutions of Cellulose and Cellulose Derivatives – A Research and Development Topic of the TITK eV

Modification, forming and analytical characterisation of cellulose and cellulose solutions represents one of the most important research topics of the Thuringian Institute for Textiles and Plastics Research (TITK). The presentation provides information on the current capabilities of the institute and on the analytical methods developed in these fields.