Stefan Matejcik

Stefan Matejcik
Comenius University Bratislava · Department of Experimental Physics

Professor

About

281
Publications
46,975
Reads
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3,889
Citations
Introduction
Electron and Ion physics, Mass spectrometry, Ion Mobility Spectrometry, UV-VIS spectrometry, Plasma Physics
Additional affiliations
January 1998 - December 2020
Comenius University Bratislava
Position
  • Professor (Full)
January 1998 - present
Comenius University Bratislava
Position
  • Principal Investigator
Education
September 1993 - November 1995
University of Innsbruck
Field of study
  • Physics
September 1991 - June 1998
Comenius University Bratislava
Field of study
  • Physics
September 1986 - June 1991
Comenius University Bratislava
Field of study
  • Physics

Publications

Publications (281)
Chapter
Technika IMS-MS będąca połączeniem spektrometrii ruchliwości jonów (IMS) i spektrometrii mas (MS) wykorzystywana jest do zadań analitycznych, w których wymagane jest rozdzielanie składników próbki o zbliżonych masach. W ostatnich latach zainteresowanie tą techniką wzrosło, a głównymi obszarami zastosowań są badania medyczne, proteomika i metabolomi...
Article
In nuclear fusion reactors, plasmas are heated to very high temperatures of more than 100 million kelvin and, in so-called tokamaks, they are confined by magnetic fields in the shape of a torus. Light nuclei, such as deuterium and tritium, undergo a fusion reaction that releases energy, making fusion a promising option for a sustainable and clean e...
Article
An atmospheric Pressure Field Effect (APFE) ionisation source for drift tube ion mobility spectrometry has been developed for operation in positive and negative polarities. The formation of negative and positive ions in synthetic air was studied and compared with the Atmospheric Pressure Corona Discharge (APCD) ionisation source. The APFE ionisatio...
Article
The excitation of nitromethane (CH3NO2), which is an important propellant and prototypic molecule for large class of explosives, has been investigated by electron impact and subsequent emission of photons in the UV‐VIS spectral region between 300 nm and 670 nm. Emission spectrum of nitromethane was recorded at an electron energy of 50 eV. New disso...
Article
Full-text available
An online coupling of microchip isotachophoresis (µITP) with ion mobility spectrometry (IMS) using thermal evaporation interface is reported for the first time. This combination integrates preconcentration power of the µITP followed by unambiguous identification of trace compounds in complex samples by IMS. Short-chain carboxylic acids, chosen as m...
Article
Full-text available
In this study, we have demonstrated a separation of positional isomers of some derivatives of alkoxyphenylcarbamic acid. These compounds belong to drugs with local anesthetics activity. The low volatility compounds were analysed by a Thin Layer Chromatography (TLC) and Ion Mobility Spectrometry (IMS) using diode laser desorption for sample introduc...
Article
Full-text available
In this paper, the rate coefficients (k) and activation energies (Ea) for SiCl4, SiHCl3, and Si(CH3)2(CH2Cl)Cl molecules in the gas phase were measured using the pulsed Townsend technique. The experiment was performed in the temperature range of 298–378 K, and carbon dioxide was used as a buffer gas. The obtained k depended on temperature in accord...
Poster
The performance of ion mobility spectrometry (IMS) instruments is influenced by the intensity and stability of the ion source and the homogeneity of the gas flow and drift field of the IMS drift tube. These parameters have been studied and optimized using experiments and computer simulations. In the case of corona discharge ion source, we have test...
Article
Rationale: Phthalates are widely used in consumer products in the chemical industries. Due to their abundance in the milieu, their potentially harmful effect on the environment, human and animal health there is a need for sensitive and fast methods for their detection. Methods: Positive polarity Corona Discharge Atmospheric Pressure Chemical Ion...
Article
Full-text available
Ion mobility spectrometry was used to monitor the degradation of phthalate vapors by corona discharge. Three different phthalates (dimethyl [DMP], diethyl [DEP], and dipropyl [DPP]) were examined in a corona discharge reactor (wire‐to‐cylinder geometry) at direct current positive polarity in ambient air. The relative removal efficiencies up to 96%...
Article
This paper reports on the variation of the physical properties of vacuum breakdown in microgaps from the static to the pulsed electric fields in a quasi-homogeneous electric field. The measurements were performed between the spherical cathode and planar anode, both made of stainless-steel separated from 1 μm up to 10 μm at the pressure of ∼1×10−4 P...
Conference Paper
The stability of the operation of the negative corona discharge ion source for the Ion Mobility Spectrometry (IMS) has been studied. The temporal stability of the ion current was investigated as a function of wire diameter (20, 50, and 100µm) and wire material (the high-voltage electrode). The ion current generation efficiency was increasing for th...
Article
Full-text available
In this paper, we describe an efficient, massively parallel GPU implementation strategy for speeding up one-dimensional electrostatic plasma simulations based on the Particle-in-Cell method with Monte-Carlo collisions. Relying on the Roofline performance model, we identify performance-critical points of the program and provide optimised solutions....
Article
Full-text available
The electron impact excitation of N 2 O was studied using the crossed electron-molecular beams method. Optical emission spectrum initiated by 50 eV electron impact was recorded within the range 200-700 nm. Main emission bands arise from excited ion state N 2 O + (A 2 Σ) and dissociative excitation into N 2 + (B 2 Σ + u). The rotationally un-resolve...
Article
A rapid and simple method is proposed for detection of elemental mercury (Hg) vapor by ion mobility spectrometry (IMS). Negative corona discharge (CD) as the ionization source and chloroform as the dopant gas were used to produce Cl⁻ reactant ion. A mass spectrum of the product ions confirmed that the mechanism of ionization is based on Cl⁻ anion a...
Article
Phthalates are widely industrially used and their toxicity is of serious environmental and public health concern. Chemical ionization (CI) analytical techniques offer the potential to detect and monitor traces of phthalate vapours in air or sample headspace in real time. Promising techniques include selected ion flow tube mass spectrometry (SIFT-MS...
Article
We present an experimental and theoretical study of electron ionization (EI) of Cyclopropylamine (CPA) molecule, using crossed electron – molecular beam technique with mass spectrometric detection of the ions. We have obtained energy resolved mass spectra, and electron energy dependent ion efficiency curves for ions of particular mass charge ratios...
Article
We present the design, construction, and first spectra of a step-scan Michelson Fourier-transform spectrometer for optical emission spectroscopy in the UV–VIS spectral range. The mirror motion mechanism is based on a long-travel piezo-based linear translation stage with built-in position feedback. The step-scan arrangement allows for signal integra...
Article
In this work, we present the application of a fast and sensitive microanalytical method, microchip capillary electrophoresis (MCE), for the determination of NO2− and NO3− ions in deionized water treated by atmospheric pressure plasma jet (APPJ). The MCE technique consisted of an online combination of isotachophoresis with zone electrophoresis, both...
Article
The present study compares the operation of two cold atmospheric plasma jet (CAPJ) configurations: needle‐to‐cylinder electrode configuration (CAPJ I) and single high‐voltage cylinder electrode around the quartz tube (CAPJ II). The CAPJs were operated in argon flowing through a quartz capillary with 0.5‐mm inner diameter into the ambient air, and t...
Article
Full-text available
A global heat flux model based on a fractional derivative of plasma pressure is proposed for the heat transport in fusion plasmas. The degree of the fractional derivative of the heat flux, α, is defined through the power balance analysis of the steady state. The model was used to obtain the experimental values of α for a large database of the Joint...
Article
In this work, we present an Atmospheric Pressure Chemical Ionisation (APCI) study of several organic solvents relevant to Thin Layer Chromatography (TLC) (methanol, ethanol, propan-2-ol, acetone, ethyl acetate, diethylamine). The solvents were investigated using an Ion Mobility Spectrometry (IMS) combined with orthogonal acceleration Time Of Flight...
Article
An Ion Mobility Spectrometry (IMS) apparatus has been used to detect the β-methyl-γ-octalactone (Whisky Lactone - WL) standard in the air and as well WL vapours originating from the oak wood samples. The IMS was equipped with Atmospheric Pressure Chemical Ionisation (APCI) ion source based on a Corona Discharge (CD) and was operated in the positive...
Preprint
Full-text available
We studied dissociation reactions of electron impact on water vapor for several fragment species at optical and near ultraviolet wavelengths (200 - 850 nm). The resulting spectrum is dominated by the Hydrogen Balmer series, by the OH (A $^2\Sigma^+$ - X $^2\Pi$) band, and by the emission of ionic H$_2$O$^+$ (A $^2$A$_1$ - X $^2$B$_1$) and OH$^+$ (A...
Article
This is the first report of coupling of microchip electrophoresis (MCE) with ion mobility spectrometry (IMS) for the analysis of liquid samples. Zone electrophoresis, employed on a microchip as a MCE technique, is suitable for coupling with IMS. Sample components separated electrophoretically in liquid phase were transferred from the microchip usin...
Article
Results from two different sets of JET experiments are presented. In experiments in which toroidicity-induced Alfven eigenmodes (TAEs) localized at different radial locations had the same frequencies and toroidal mode numbers, the occurrence of enhanced losses after the excitation of TAEs in the core of the plasma was observed. On the contrary, enh...
Article
In this work we have studied ionisation mechanism of Atmospheric Pressure Chemical Ionisation (ACPI) for three isomers of dimethyl phthalate (dimethyl phthalate – DMP (ortho - isomer), dimethyl isophthalate – DMIP (meta) and dimethyl terephthalate – DMTP (para)) using Ion Mobility Spectrometry (IMS) and IMS combined with orthogonal acceleration Tim...
Article
Protonation, hydration, and cluster formation of ammonia, formaldehyde, formic acid, acetone, butanone, 2-ocatanone, 2-nonanone, acetophenone, ethanol, pyridine, and its derivatives were studied by IMS-TOFMS technique equipped with a corona discharge ion source. It was found that tendency of the protonated molecules, MH⁺, to participate in hydratio...
Article
Full-text available
In this work, we present the results of an experimental study focused on characterisation of an electron gun designed for atmospheric pressure ionisation - Atmospheric Pressure Electron Gun (APEG). The APEG generates electrons with energies of several keV and could be used as replacement for β-radiation-based ionization sources for Atmospheric Pres...
Article
Ionization of 2-nonanone, cyclopentanone, acetophenone, pyridine, and di-tert-butylpyridine (DTBP) in a corona discharge (CD) atmospheric pressure chemical ionization (APCI) ion source was studied using ion mobility (IMS) and time-of-flight mass spectrometry (TOF-MS). The IMS and MS spectra were recorded in the absence and presence of ammonia dopan...
Article
Experimental investigation of electron ionization (EI) of and electron attachment (EA) onto dicyclohexyl phthalate (DCHP) was carried out using a crossed electron and molecular beam technique. Formation of positive and negative ions by EI and EA with the corresponding dissociation processes was studied and discussed. Due to a low ion yield of the p...
Article
A negative corona discharge operating at atmospheric pressure has been used to initiate chemical reactions in a gaseous mixture of nitrogen, methane, and carbon dioxide. Such a mixture simulates the composition of the early Earth's atmosphere. This work extends our previous experimental studies of the chemistry of prebiotic atmospheres generated in...
Article
In a combined experimental and theoretical study we characterize dissociative electron attachment (DEA) to, and electronically excited states of, Fe(CO)$_5$. Both are relevant for electron-induced degradation of Fe(CO)$_5$. The strongest DEA channel is cleavage of one metal-ligand bond that leads to production of Fe(CO)$_4^-$. High-resolution spect...
Article
Full-text available
In the present study we have performed electron collision experiments with copper carboxylate complexes: [Cu2(t-BuNH2)2(µ-O2CC2F5)4], [Cu2(s-BuNH2)2(µ-O2CC2F5)4], [Cu2(EtNH2)2(µ-O2CC2F5)4], and [Cu2(µ-O2CC2F5)4]. Mass spectrometry was used to identify the fragmentation pattern of the coordination compounds produced in crossed electron – molecular b...
Article
2,4,6-trichloroanisole and 2,4,6-tribromoanisole were investigated by means of electron transmission spectroscopy and two different types of dissociative electron attachment spectrometers. The results obtained were interpreted with the support of density functional theory calculations. The dominant dissociative decay channels of the temporary molec...
Article
Full-text available
In this work, we probe anion production upon electron interaction with Fe(CO)5 clusters using two complementary cluster-beam setups. We have identified two mechanisms that lead to synthesis of complex anions with mixed Fe/CO composition. These two mechanisms are operative in distinct electron energy ranges. It is shown that the elementary decomposi...
Article
Full-text available
The 2014–2016 JET results are reviewed in the light of their significance for optimising the ITER research plan for the active and non-active operation. More than 60 h of plasma operation with ITER first wall materials successfully took place since its installation in 2011. New multi-machine scaling of the type I-ELM divertor energy flux density to...
Article
Full-text available
This paper reports on experimental studies of the breakdown mechanism in oxygen microdischarges generated in static and time-varying electric fields, up to radio-frequencies. Measurements were performed by using electrodes with round edges separated by a distance ranging between 2.5 μm and 100 μm, with the gas pressure from 7.5Torr to 700Torr. It i...
Article
Full-text available
The electron impact excitation-emission cross section of argon 4P²[1/2] → 4S²[1/2]° [1] was experimentally investigated in the electron energy range 5eV − 100eV. The absolute value of the cross section was calibrated by comparison with the known cross section for the helium transition He 3¹S → 2¹P⁰ [2].
Article
Full-text available
We report our recent experimental study regarding H2 and D2 continuum radiation (a³Σg⁺ → b³Σu⁺) in the spectral range of 200 – 650 nm, excited by electron impact at near-threshold impact energies. In contrast to earlier studies, present results indicate that H2 and D2 continuum radiation is detectable in the spectral range above 500 nm. To suppleme...
Article
Full-text available
The optical emission spectrum of acetylene excited by monoenergetic electrons was studied in the range of 190–660 nm. The dissociative excitation and dissociative ionization associated with excitation of the ions initiated by electron impact were dominant processes contributing to the spectrum. The spectrum was dominated by the atomic lines (hydrog...
Article
In this paper, the results of measurements of the characteristics of the hydrogen microdischarges from direct current to radio frequencies are presented and discussed. Two types of the electrode configurations are used: electrodes with Bruce profile and glass melting electrodes separated between 2.5 and 100 μm. The breakdown voltage values for low...
Article
This paper presents the results of the experimental and simulation studies of the breakdown characteristics of microdischarges in compressed ambient air under the influence of static and time-varying electric fields, up to radio-frequencies. The measurements were performed for sphere to plane geometry of the electrodes separated from 5 μm to 100 μm...
Article
The exploration of planetary atmosphere is being advanced by the exciting results of the Cassin-Huygens mission to Titan. The complex chemistry revealed in such atmospheres leading to the synthesis of bigger molecules is providing new insights into our understanding of how life on Earth developed. This work extends our previous investigation of nit...
Data
We present a novel method for solids and surfaces analysis by Ion mobility spectrometry. The Advance ion mobility spectrometer (AIMS) operated in subatmospheric pressure was used in this work. The capillary inlet was used for sample aspiration to reaction region of AIMS. The sample was desorbed from surface by laser diode module. This technique was...
Conference Paper
Full-text available
Purpose: We present a novel method for coupling thin layer chromatography (TLC) with ion mobility spectrometry (IMS) using laser desorption technique (LD). After separation of the compounds by TLC, the TLC surface was sampled by the LD-IMS without any further manipulation or preparation. Experimental description: The Advance ion mobility spectromet...
Article
Full-text available
This work extends our previous experimental studies of the chemistry of Titan’s atmosphere by atmospheric glow discharge. The Titan’s atmosphere seems to be similarly to early Earth atmospheric composition. The exploration of Titan atmosphere was initiated by the exciting results of the Cassini-Huygens mission and obtained results increased the int...
Presentation
Full-text available
We present a novel method for surface analysis by Ion mobility spectrometry. The Advance ion mobility spectrometer (AIMS) operated in subatmospheric pressure was used in this work. The capillary inlet was used for sample aspiration to reaction region of AIMS. The sample was desorbed from surface by laser diode module. This technique was successfull...
Article
Full-text available
We report results of an experimental study focused on the fluorescence of H2 initiated by the impact of quasi-monochromatic electrons. The emission spectra of H2 molecules at electron energies of 25 eV, 50 eV and 100 eV have been measured in the spectral range of 320–670 nm. The emission spectrum is dominated by Balmer emission lines, Fulcher α, β,...
Article
Although microchip electrophoresis (MCE) is intended to provide reliable quantitative data, so far there is only limited attention paid to these important aspects. This study gives a general overview of key aspects to be followed to reach high-precise determination using isotachophoresis (ITP) on the microchip with conductivity detection. From the...
Article
We present a novel method for coupling thin layer chromatography (TLC) with ion mobility spectrometry (IMS) using laser desorption technique (LD). After separation of the compounds by TLC, the TLC surface was sampled by the LD-IMS without any further manipulation or preparation. The position of the laser was fixed and the TLC plate was moved in des...
Article
An important direction of fusion research is the reconstruction of plasma equilibrium from measurements. Most of the plasma modeling codes and plasma control systems use equilibrium data on input. Therefore, the accuracy of reconstructions plays a crucial role in fundamental understanding of processes in present-day devices and fusion reactors. The...
Article
The exploration of planetary atmosphere is being advanced by the exciting results of the Cassin-Huygens mission to Titan. The complex chemistry revealed in such atmospheres leading to the synthesis of bigger molecules is providing new insights into our understanding of how life on Earth developed. In our experiments Titan's atmosphere is simulated...
Article
In this paper results of the experimental and theoretical studies of the field emission driven direct current argon microdischarges for the gaps between 1 μm and 100 μm are presented and discussed. The breakdown voltage curves and Volt-Ampere characteristics proved to be a fertile basis providing better understanding of the breakdown phenomena in m...
Article
This paper contains the results of experimental studies of the breakdown phenomena in hydrogen microdischarges from direct current to very high radio frequencies. Measurements were performed for two types of electrode configurations, glass melting electrodes and electrodes with Bruce profiles, by varying the gap size from &$2.5\mu \text{m} $ ; to &...
Article
Atmospheric pressure non-equilibrium plasmas (APPs) are effective source of radicals, metastables and a variety of ions and photons, ranging into the vacuum UV spectral region. A detailed study of these species is important to understand and tune desired effects during the interaction of APPs with solid or liquid materials in industrial or medical...
Article
We present a new technique suitable for direct liquid sampling and analysis by ion mobility spectrometry (IMS). The technique is based on introduction of a droplet stream to the IMS reaction region. The technique was successfully used to detect explosives dissolved in methanol and oil as well as to analyze amino acids and dipeptides. One of the mai...
Article
Full-text available
This paper reports the results of an extensive study of with the in situ mass spectrometry analysis of gaseous phase species produced by an atmospheric plasma glow discharge in N2-CH4 gas mixtures (with methane concentrations ranging from 1% to 4%). The products are studied using proton-transfer-reaction mass spectrometry (PTR-MS). HCN and CH3CN ar...
Article
This topical issue on " Elementary processes with atoms and molecules in isolated and aggregated states " was motivated by the 6th Conference on Elementary Processes in Atomic Systems – CEPAS, which was held from July 9–12, 2014 in Bratislava, Slovakia. The conference program overlaps with the topic of this issue. The scientific papers in the topic...
Article
Full-text available
In this study we have examined the formation of ions from hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) sample evaporated at 473 K in reactions with reactant ions (RI) produced in negative corona discharge (CD). The ions have been analysed and detected by ion mobility spectrometry coupled to orthogonal acceleration time of flight spectrometer (IMS-...
Article
Full-text available
The processes of dissociative excitation (DE) and dissociative ionisation with excitation (DIE) of iron pentacarbonyl, Fe(CO)5, have been studied using a crossed electron-molecule beam experimental apparatus (Electron Induced Fluorescence Apparatus, EIFA). Using EIFA we were able to record the emission spectrum of the molecule in the UV-VIS range,...
Article
In this paper, we report presence of various organic products formed in a flowing atmospheric glow discharge fed by gas mixture containing 1-5 % of methane in nitrogen, which mimics the Titan's atmosphere. Gaseous products from the discharge exhaust were analysed by Gas Chromatography with Mass Spectrometry (GC-MS). The experimental results reveale...