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Wyniki wyszukiwania dla: GAS CHROMATOGRAPHY COUPLED WITH MASS SPECTROMETRY (GC-MS)
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Prediction of Overall In Vitro Microsomal Stability of Drug Candidates Based on Molecular Modeling and Support Vector Machines. Case Study of Novel Arylpiperazines Derivatives
PublikacjaOther than efficacy of interaction with the molecular target, metabolic stability is the primary factor responsible for the failure or success of a compound in the drug development pipeline. The ideal drug candidate should be stable enough to reach its therapeutic site of action. Despite many recent excellent achievements in the field of computational methods supporting drug metabolism studies, a well-recognized procedure to model...
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Revealing dynamic changes of the volatile profile of food samples using PTR–MS
PublikacjaVolatile compounds carry valuable information regarding the properties of foodstuffs. Volatiles emitted from food can be used as, for example, indicators of quality, shelf-life, or authenticity. A better understanding of the multitude of transformations which occur during food processing could facilitate the optimisation of production, increase the desirability of food products, and also their wholesomeness. However, as some of...
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Fast GC as a useful tool for authenticity assessment of kiwifruit
PublikacjaKiwifruit is one of the healthiest fruits due to its high content of biologically active substances and nutrients. The most popular species of Actinidia (kiwifruit) are the Actinidia deliciosa fruits called kiwi and Actinidia chinensis commonly called golden kiwi, while the lesser known species is Actinidia arguta known as mini kiwi. Bioactivities and nutrients of Actinidia are influenced by species and cultivars. It is very important...
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Comparative evaluation of different methods for determining phytochemicals and antioxidant activity in products containing betalains - Verification of beetroot samples
PublikacjaThis study presents methods that can be used to assess the health quality of products containing betalains. The paper compares and verifies data on the phytochemical composition of three different pigmented beetroot cultivars using spectrophotometric, HPLC-DAD, HPTLC and LC-Q-Orbitrap-HRMS techniques. Additionally, we compared the total antioxidant activity in both the cell-free and cellular systems. Betalain contribution to antioxidant...
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Synthesis and structural characterization of bio-based bis(cyclic carbonate)s for the preparation of non-isocyanate polyurethanes
PublikacjaBio-based cyclic carbonates are of significant research interest as monomers for non-isocyanate polyurethane (NIPU) synthesis. This research describes the synthesis of a series of five-membered bis(cyclic carbonate)s using bio-based polyether polyols (PO3G) with different molecular weights (250, 650 and 1000 g mol−1) and carbon dioxide as green feedstocks. The utilization of CO2 as a source of carbon in the chemical reaction is...
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In-tube extraction for the determination of the main volatile compounds in Physalis peruviana L
PublikacjaAn analytical procedure based on in-tube extraction followed by gas chromatography with mass spectrometry has been developed for the analysis of 24 main volatile components in cape gooseberry (Physalis peruviana L.) samples. According to their chemical structure, the compounds were organized into different groups: one hydrocarbon, one aldehyde, four alcohols, four esters, and 14 monoterpenes. By single-factor experiments, incubation...
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Rapid Evaluation of Poultry Meat Shelf Life Using PTR-MS
PublikacjaThe use of proton transfer reaction mass spectrometry (PTR-MS) for freshness classification of chicken and turkey meat samples was investigated. A number of volatile organic compounds (VOCs) were selected based on the correlation (> 95%) of their concentration during storage at 4 °C over a period of 5 days with the results of the microbial analysis. In order to verify if the selected compounds are not sample-specific, a number...
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MRM–MS of marker peptides and their abundance as a tool for authentication of meat species and meat cuts in single-cut meat products
PublikacjaThe abundance of protein markers in different types of meat cuts was explored in the context of authentication of raw meat (pork, beef and chicken) and processed meat products. Peptides originating from myoglobin (Mb) and myosin (My) were analyzed using multiple reaction monitoring mass spectrometry (MRM–MS). Analytical protocol was optimized for good repeatability (CV < 10%) and high sensitivity. The MS signal intensity of Mb...
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Occurrence and seasonal variations of 25 pharmaceutical residues in wastewater and drinking water treatment plants
PublikacjaThousands of tons of pharmaceuticals are introduced into the aqueous environment due to their incomplete elimination during treatment process in wastewater treatment plants (WWTPs) and water treat- ment plants (WTPs). The presence of pharmacologically active compounds in the environment is of a great interest because of their potential to cause negative effects. Furthermore, drugs can undergo different pro- cesses leading to the...
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Long-Term Stability of Benzodiazepines and Z-Hypnotic Drugs in Blood Samples Stored at Varying Temperatures
PublikacjaBenzodiazepines (BZDs) and Z-drugs are among the most commonly prescribed pharmaceuticals in the world and are considered standard care for various mental illnesses and for treatment of sleeping and anxiety disorders, alcohol withdrawal, muscle spasms and epilepsy. Some BZDs are not allowed as pharmaceuticals in many countries, and they are used as "designer benzodiazepines" (DBZDs). All these compounds are typically screened in...
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Influence of reactive oxygen species during deposition of iron oxide films by high power impulse magnetron sputtering.
PublikacjaIron oxide films were deposited using high power impulse magnetron sputtering (HiPIMS) of an iron cathode in an argon/oxygen gas mixture at different gas pressures (0.5~Pa, 1.5~Pa, and 5.0~Pa). The HiPIMS system was operated at a repetition frequency $f = 100$~Hz with a duty cycle of 1~\%. A main goal is a comparison of film growth during conventional and electron cyclotron wave resonance-assisted HiPIMS. The deposition plasma...
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Ionogel sorbent coatings for determining organophosphorus and pyrethroid insecticides in water and fresh juice samples by headspace-solid phase microextraction
PublikacjaThe sol–gel method yielded three different ionogel sorbent coatings that were obtained based on a silica material containing ionic liquids (ILs) immobilized in its pores. Two ILs, triethylsulfonium bis(trifluoromethylsulfonyl) imide [Set3][TFSI] and 1-butyl-1-methylpiperidinium bis(trifluoromethylsulfonyl)imide [C4C1Pip][TFSI], as well as their equimolar mixture [Set3/C4C1Pip], were used to obtain ionogel fibers. The developed...
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Head-Space SPME for the Analysis of Organophosphorus Insecticides by Novel Silica IL-Based Fibers in Real Samples
PublikacjaThis work demonstrates the suitability of a newly developed ionic liquid (IL)-based silica SPME fiber for the determination of seven organophosphorus insecticides in cucumber and grapefruit samples by headspace solid-phase microextraction (HS-SPME) with a gas chromatography–flame ionization detector (FID). The sol-gel method released four different sorbent coatings, which were obtained based on a silica matrix containing ILs immobilized...
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Distinction of clenbuterol intake from drug or contaminated food of animal origin in a controlled administration trial – the potential of enantiomeric separation for doping control analysis
PublikacjaThe differentiation of clenbuterol abuse and unintentional ingestion by contaminated meat is crucial with respect to the valuation of an adverse analytical finding in human sports doping control. The proportion of the two enantiomers of clenbuterol may serve as potential discriminating parameter. For the determination of the individual enantiomers, specific methods were developed and validated for the different matrices under investigation...
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Simultaneous opto-electrochemical monitoring of carbamazepine and its electro-oxidation by-products in wastewater
PublikacjaThe growing human impact on aquatic environments, due to the extensive use of pharmaceuticals and the release of persistent pollutants, makes it necessary to implement new widespread methods for the characterisation and quantification of such contaminants and relative degradation products. Carbamazepine, 5H-dibenzo[b,f]azepine-5-carboxamide, (CBZ) is a widely used anti-epileptic drug, characterised by its limited removal by conventional...
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Production of essential oils from in vitro cultures of Caryopteris species and comparison of their concentrations with in vivo plants
PublikacjaThe chemical composition of hydrodistilled essential oils obtained from aerial parts and roots of selected Caryopteris (‘bluebeard’) species (C. incana, C. mongolica, Caryopteris 9 clandonensis), as well as the newly established in vitro shoot and adventitious root cultures of the above plants, was analyzed by gas chromatography– mass spectrometry. Essential oil content and composition differed significantly depending on the type...
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Relative quantification of pork and beef in meat products using global and species-specific peptide markers for the authentication of meat composition
PublikacjaWe used global and species-specific peptide markers for a relative quantitative determination of pork and beef in raw and processed meat products made of the two meat species. Four groups of products were prepared (i.e., minced raw meats, sausages, raw and fried burgers) in order to represent products with different extents of food processing. In each group, the products varied in the pork/beef proportions. All products were analysed...
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Reactive deposition of TiNx layers in a DC-magnetron discharge
PublikacjaTiNx layers have been deposited in 'balanced mode' and 'unbalanced mode' of a reactive DC-magnetron plasma (carrier gas argon, reactive gas nitrogen) under different conditions. Discharge power and reactive gas flow have been varied. The layers have been examined by X-ray photoelectron spectroscopy (XPS), X-ray reflectometry (XR), and spectroscopic ellipsometry (SE). The results of the layer analyses were combined with plasma investigations...
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Influence of Diosmin Treatment on the Level of Oxidative Stress Markers in Patients with Chronic Venous Insufficiency
PublikacjaOxidative stress plays an important role in the pathophysiology of many human disorders, while antioxidants prevent the development of various adverse symptoms. Diosmin is a natural flavonoid applied in vascular system disorders, especially in chronic venous insufficiency (CVI), and it plays a significant part in the alleviation of CVI symptoms. Due to antioxidant activity, it also has the ability to scavenge the oxygen free radicals...
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Electrochemistry meets enzymes: Investigation of the biotransformation pathway of C-1311 based on electrochemical simulation in comparison to in vitro methods.
PublikacjaThe knowledge of the metabolic pathways and the biotransformation of new drugs is one of the major challenges in pharmaceutical research. It is crucial for elucidation of degradation routes of the new biologically active compounds, especially in the area of possible toxicity. Conventional in vitro drug metabolism studies are based on incubating drug candidate with e.g. hepatocytes or, most importantly, liver cell microsomes and...
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Nowe metodyki oznaczania dodatków do paliw z zastosowaniem rozdzielenia wielopomiarowego = New procedures for fuel additives determination by multidimensional separation systems
PublikacjaW pracy przedstawiono wyniki badań nad opracowaniem metodyki oznaczania wybranych dodatków "myjących" w paliwie diesla. Porównano metodyki jednoetapowe z wykorzystaniem chromatografii gazowej z detektorem płomieniowo-jonizacyjnym (GC-FID) lub spektrometrem mas (GC-MS) oraz wysokosprawnej chromatografii cieczowej z detektorem UV z matrycą fotodiodową (HPLC-UV-DAD), z metodykami dwuetapowymi, w których do wstępnej izolacji składników...
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The analysis of raw spirits – a review of methodology
PublikacjaAgricultural distillates (raw spirits) are alc oholic l iquids obtained thro ugh dis till ation (preceded by alcoholic ferm entation)of specific agricultural products that do not have the properties of ethyl alcohol or a spirit, but still retain th e aroma andtaste of the raw ingredients used. This review is a brief overview of agricultural distillates and of some methods commonlyused (GC-MS, GC-FID, GC-O, electronic nose) for...
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Ionogel fibres of bis(trifluoromethanesulfonyl)imide anion-based ionic liquids for the headspace solid-phase microextraction of chlorinated organic pollutants
PublikacjaIonogels, a family of hybrid materials in which ionic liquids (ILs) are confined in a sol–gel network, are receiving much attention in a variety of scientific and technological fields. In this work, ionogels derived from three different ILs based on the anion bis(trifluoromethanesulfonyl)imide (TFSI), namely 1-butyl- 3-methylpyridinium bis(trifluoromethanesulfonyl)imide ([C4C1Py][TFSI]), 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide...
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Chemical, Aroma and Pro-Health Characteristics of Kaffir Lime Juice—The Approach Using Optimized HS-SPME-GC-TOFMS, MP-OES, 3D-FL and Physiochemical Analysis
PublikacjaThe study aimed to provide the chemical, aroma and prohealth characteristics of the kaffir lime juice. A procedure using solid-phase microextraction with gas chromatography (SPME-GC-TOFMS) was optimized and validated for the determination of terpenes of kaffir lime. Main physicochemical parameters: pH, vitamin C, citric acid and °Brix were evaluated. Micro- and macro elements were determined using microwave plasma optic emission...
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GTR/Thermoplastics Blends: How Do Interfacial Interactions Govern Processing and Physico-Mechanical Properties?
PublikacjaIn this work, GTR/thermoplastics blends (in ratio 50/50 and 75/25 wt.%) were prepared by melt-compounding in an internal mixer. During research, trans-polyoctenamer rubber (TOR), ethylene-vinyl acetate copolymer (EVA), ethylene-octene copolymer (EOC), and linear low-density polyethylene (LLDPE), were used in their thermoplastic phase. Microstructure and processing-performance property interrelationships of the studied materials...
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Differences between selected volatile aromatic compound concentrations in sludge samples in various steps of wastewater treatment plant operations
PublikacjaSewage sludge, one of the main wastes generated during wastewater treatment, constitutes an important source of emissions of volatile chemical compounds such as volatile aromatic compounds These substances may undergo various changes as a result of operations and unit processes, which affects their concentrations in sewage sludge. An important factor determining the potential hazardousness of volatile organic compounds is the quality...
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Phototransformation of Amlodipine: Degradation Kinetics and Identification of Its Photoproducts
PublikacjaNowadays, monitoring focuses on the primary compounds and does not include degradation products formed during various biological and chemical processes. Transformation products may have the same effects to human health and the environment or sometimes they can be more toxic than the parent compound. Unfortunately, knowledge about the formation of degradation products is still limited, however, can be very important for the environmental...
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Structure and Stability Characterization of Natural Lake Pigments Made from Plant Extracts and Their Potential Application in Polymer Composites for Packaging Materials
PublikacjaNatural dyes were extracted from various plant sources and converted into lake pigments based on aluminum and tin. Three different plants (weld, Persian berries, and Brazilwood) were chosen as representative sources of natural dyes. High-performance liquid chromatography (HPLC) and triple-quadrupole mass spectrometry (QqQ MS) were used to identify dyestuffs in the raw extracts. The natural dyes and lake pigments were further characterized...
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Recent Developments in Data-Assisted Modeling of Flexible Proteins
PublikacjaMany proteins can fold into well-defined conformations. However, intrinsically-disordered proteins (IDPs) do not possess a defined structure. Moreover, folded multi-domain proteins often digress into alternative conformations. Collectively, the conformational dynamics enables these proteins to fulfill specific functions. Thus, most experimental observables are averaged over the conformations that constitute an ensemble. In this...
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Dissociative electron attachment to the radiosensitizing chemotherapeutic agent hydroxyurea
PublikacjaDissociative electron attachment to hydroxyurea was studied in the gas phase for electron energies ranging from zero to 9 eV in order to probe its radiosensitizing capabilities. The experiments were carried out using a hemispherical electron monochromator coupled with a quadrupole mass spectrometer. Diversified fragmentation of hydroxyurea was observed upon low energy electron attachment and here we highlight the major dissociation...
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Thermal degradation kinetics of poly(propylene succinate) prepared with the use of natural origin monomers
PublikacjaLinear biobased polyester polyols were prepared with the use of succinic acid and 1,3-pro- panediol (both with natural origin). Tetraisopropyl orthotitanate (TPT) was used as a catalyst. In order to determine the effect of various synthesis temperature conditions on the thermal degradation kinet- ics, nine sequences of temperature conditions were used during two-step polycondensation reaction. Thermogravimetric analysis was conducted...
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Influence of chemical structure on physicochemical properties and thermal decomposition of the fully bio-based poly(propylene succinate-co-butylene succinate)s
PublikacjaIn this work, two polyesters and four copolyesters were studied. All materials were synthesized to obtain the monomers dedicated for thermoplastic polyurethane elastomers. For this type of PUR, the monomers should characterize by appropriate selected physicochemical properties and macromolecular structure distribution, which depends on synthesis conditions. The study of chemical structure with extensive and knowledgeable analysis...
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An energetic analysis of a gas turbine with regenerative heating using turbine extraction at intermediate pressure - Brayton cycle advanced according to Szewalski's idea
PublikacjaIn this paper, a modification of a simple gas turbine into the Brayton cycle with regenerative heating, using turbine extraction at intermediate pressure, is presented. The main concept of the retrofitting is based on the transfer of heat from the turbine exhaust gases to the air entering the combustion chamber. The extracted gas transfers heat to air via the divided regenerative heat exchanger and after that is compressed and...
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New approach for e-cigarette aerosol collection by an original automatic aerosol generator utilizing melt-blown non-woven fabric
PublikacjaCurrently, there is lack of standardized conditions for the collection and analysis of e-cigarette (EC) aerosol. Considering the urgent need for the development of these guidelines, a procedure for EC aerosol analysis was developed. A novel automatic e-cigarette aerosol generator was designed. For the first time, melt-blown non-woven fabric was applied for the effective uptake of compounds released from vaporized e-liquid. The...
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Evaluation of the suitability of electronic nose based on fast GC for distinguishing between the plum spirits of different geographical origins
PublikacjaPlum spirits are obtained exclusively via the alcoholic fermentation and distillation of meaty plums or must composed of plums, with or without stones. The European countries such as Poland, the Slovak Republic, the Czech Republic, Bulgaria and Romania are the leading producers of this alcoholic beverage. Information about the authentication of plum spirits produced in different countries can be found in the published literature....
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Zastosowanie chromatografii gazowej w analityce technicznej do charakterystyki ksylenu technicznego na potrzeby rejestracji w systemie REACH
PublikacjaW pracy przedstawiono metodykę badań ksylenu technicznego w celu jego charakterystyki zgodnie z wymaganiami rejestracyjnych systemu REACH. W badaniach zastosowano technikę chromatografii gazowej z detektorem płomieniowo-jonizacyjnym (GC-FID) oraz w sprzężeniu ze spektrometrią mas (GC-MS) Chromatografia gazowa umożliwia wykonanie dwóch fundamentalnych oznaczeń tego typu mieszaniny – tzn. zbadania czystości mieszaniny oraz identyfikacji...
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Emission profile of butan-2-one oxime from commercially available neutral silicone sealant
PublikacjaThe paper presents results of research on emission profile of butan-2-one oxime (methyl ethyl ketoxime, MEKO) released from two types of commercially available neutral silicone sealants: silicone type ‘S’ and silicone type ‘T’. To determine the emissions from silicone samples, the system consists of a stationary emission chamber, and the thermal desorption-gas chromatography-mass spectrometry system was applied. First, the research...
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Application of passive sampling technique in monitoring research on quality of atmospheric air in the area of Tczew, Poland.
PublikacjaThis paper presents the results of atmospheric air quality research in Tczew (adjacent to the Vistula River) on the content of BTEX compounds. Analytical procedure applied during the sampling of the analytes from the air used the passive sampling technique (diffusive passive sampler, Radiello®). For determination of BTEX compounds in atmospheric air, two-stage thermal desorption technique combined with gas chromatography (TD-GC-FID)...
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Structure-rheology relationship of fully bio-based linear polyester polyols for polyurethanes - Synthesis and investigation
PublikacjaThe synthesis of polyols from renewable substances as an alternative for petrochemical-based polyols play important matter in the polyurethane industry. In this work, the fully bio-based linear polyester polyols with different catalyst amounts were synthesized via two-step polycondensation method. The effect of various catalyst content on the structure and rheological behavior were established. Fourier Transform Infrared Spectroscopy,...
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Polymer biodegradable coatings as active substance release systems for urological applications
PublikacjaCatheter-associated urinary tract infections are the result of catheterization of the bladder. The risk of infection is directly proportional to the length of the bladder catheterization. Bacteria cells have the ability to adhere and create the biofilm on the surface of catheter materials. Bacteria’s biofilm is an extremely beneficial environment of existence for microorganisms. Microorganisms that are an integral part of the biofilm...
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Electron-impact ionization of fluoromethanes – Review of experiments and binary-encounter models
PublikacjaExperiments and recommended data on electron-impact ionization of methane and fluoromethanes (CH3F, CH2F2, CHF3, CF4) are reviewed and compared with binary-encounter models (Gryzinski’s, ´ Deutsch and Märk’s, and Kim and Rudd’s). A good agreement between recent experiments and the two latter classical-like models is shown. Kim and Rudd’s model (calculated presently in the restricted HartreeFock 6-31**G orbital basis) predicts well...
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Dissociative multi-photon ionization of isolated uracil and uracil-adenine complexes
PublikacjaRecent multi-photon ionization (MPI) experiments on uracil revealed a fragment ion at m/z 84 that was proposed as a potential marker for ring opening in the electronically excited neutral molecule. The present MPI measurements on deuterated uracil identify the fragment as C3H4N2O+ (uracil+ less CO), a plausible dissociative ionization product from the theoretically predicted open-ring isomer. Equivalent measurements on thymine...
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Chemistry induced by low-energy electrons in condensed multilayers of pure small organic acids
PublikacjaPrzedstawiono reakcje indukowane przez niskoenergetyczne elektrony (0.7 - 20 eV) w kondensowanych warstwach kwasu mrówkowego (HCOOH), częściowo deuterowanego kwasu octowego (CH3COOD) oraz kwasu trifluorooctowego (CF3COOD).
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Dissociation and fragmentation of furan by electron impact
PublikacjaDissociation and fragmentation processes that produce electronically excited atomic and molecular fragments, following electron impact excitation, have been studied in furan. The optical excitation technique has been employed over the electron incident energy range 15-95 eV. Formation of excited hydrogen atoms H(n) in the n = 4-10 states has been detected by observation of the Balmer series. The diatomic CH fragments are formed...
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Electron impact ionization of CCl4 and SF6 embedded in superfluid helium droplets
PublikacjaBadana była jonizacja helowych nano-kropel o rozmiarach 104 z osadzonymi wewnątrz molekułami CCl4 i SF6. Zmierzone z dużą rozdzielczością widma masowe wskazują na tworzenie dużych klasterów w przypadku CCl4. Zależność intensywności jonizacji w funkcji energii wskazuje, że w przypadku obu molekuł osadzają się one wewnątrz kropli. Zaobserwowano jon macierzysty CCl4-, prawdopodobnie powstający na drodze jonizacji Penninga podczas...
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Electron ionization induced fragmentation of fluorinated derivatives of bisphenols
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Bi-dipole-bound anions
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Possible mechanisms for protecting NCα bonds in helical peptides from electron-capture (or transfer) dissociation
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Ionization of tocopherols and tocotrienols in atmospheric pressure chemical ionization
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Reactions in nanofilms of trifluoroacetic acid (CF3COOH) driven by low energy electrons
PublikacjaBadano modyfikacje chemiczne indukowane przez niskoenergetyczne elektrony (0-20eV) w cienkich warstwach skondensowanych molekuł CF3COOH. Do badań zastosowano dwie metody: desorpcję jonów w wyniku bombardowania elektronami (ESD - Electron Stimulated Desorption) oraz termiczną desorpcję jonów (TDS - Thermal Desorption Spectroscopy).