József Borossay

Fly-attracting volatiles produced by Rhodococcus fascians and Mycobacterium aurum isolated from myiatic lesions of sheep

Bacterial strains isolated from the healthy breech mucosa and myiatic wounds of ewes were tested for their volatile production as fly attractants towards Wohlfahrtia magnifica (Diptera: Sarcophagidae). Cultures were studied as fly baits in field experiments, and strains performing with the best chemotropic effect were selected for further analysis. Static and dynamic headspace samples from shaken cultures were examined by gas chromatography-mass spectrometry (GC-MS). Strains identified as Rhodococcus fascians and Mycobacterium aurum produced various volatile sulfur compounds and benzene, and proved to be the best fly attractants.

Study of decomposition of sulphur hexafluoride by gas chromatography/mass spectrometry

When electrical discharges occur in sulphur hexafluoride gas (SF6) lower fluorides are produced within the discharge, and they in turn react readily with impurities, insulators and the electrodes. The final stable compounds formed include sulphur oxyfluorides and sulphur oxides. The aim of the present work was to optimize an analytical method for determining the decomposition products, and finding the dependence of the reaction route followed on the reaction conditions (input energy, contaminants present in the system). By performing model experiments and using various GC/MS techniques, several decomposition products were identified and correlations found between the abundances of the individual components and the decomposition conditions

Determination of furanic compounds in insulating oil by high performance liquid chromatography/mass spectrometry using atmospheric pressure chemical ionization

A method has been developed to determine furanic compounds in insulating oil matrix using liquid chromatography/mass spectrometry with atmospheric pressure chemical ionization. The examined samples were provided from model experiments and also from several high voltage functioning transformers. To increase sensitivity of the method six furanic compounds (determined by model experiments) were quantified by selected ion monitoring, and quantitation was based on the marker peaks. Oil samples were prepared using solid phase extraction. The results are suitable for evaluation of model experiments and also to solve problems of calibration. From extracts of oil samples taken from functioning transformers cellulose depolymerization products have been identified, and their amounts were found to be valuable in assessing the condition of the transformer (fault diagnosis).

Determination of bond energies of organic silicon compounds on the basis of appearance potentials

Abstract For the kinetic treatment of the rearrangement reactions of siloxanes it was necessary to study the relative bond dissociation energies of the various silicon—oxygen bonds present in the siloxane chain. Therefore, appearance potentials of the trimethyl-silyl-and trimethyl-siloxy-ions formed in the course of fragmentation were determined by means of the electron impact method, and bond dissociation energies of the corresponding bonds were evaluated. A 20% increase in the bond dissociation energy was found for the silicon—oxygen bond adjacent to the vinyl-group in vinyl-substituted siloxanes. On the basis of this finding a differential equation was established which correctly describes the rearrangement reaction of heptamethyl-3-vinyl-trisiloxane.

Matrix effect for several derivatives of benzene in water by solid phase microextraction (SPME)

SummaryLevels of several derivatives of benzene were examined in natural surface water (river Zala, West-Hungary) by solid phase micro extraction. Results from the river water samples were compared to the results from spiked double distilled water. The difference in extraction efficiency is termed a “matrix effect”. Large matrix effect causing the change of extraction efficiency experienced in this study. Relationship was found between the matrix effect and TOC, TIC, suspended and the dissolved matter content.

Pyrolysis gas chromatography of insulating polymers used in electricity generators

Abstract Pyrolysis gas chromatography was applied to the study of generator insulating materials in a nitrogen atmosphere at 500–750°C. The materials were modified polyester and epoxy resins. The samples were pyrolysed in a directly heated furnace coupled on line with a gas chromatograph. Light hydrocarbons, carbon oxides and higher-molecular-weight degradation products were identified. The polymer compositions could also be determined.

Determination of fault gases in transformer oils

Abstract A method was developed for the determination of incipient faults in oil-insulated transformers. It involves the determination of so-called fault gases (C1C3 hydrocarbons, CO and CO2) formed upon thermal degradation of the insulator oil and of the insulating materials on the cellulose base by gas chromatography, using a flame ionization detector. The carbon oxides are converted into methane using a nickel catalyst at 400°C. The reproducibility of the method is better than ± 5% relative. Examples of three types of application of the method are presented.

Extraction and quantitation of furanic compounds dissolved in oils

Furans are amongst the decomposition products which are generated by the degradation of cellulose in paper. Paper insulation is used in capacitors, cables and transformers. These furans dissolve in the impregnating mineral oil, and a method, involving liquid/liquid extraction, solid phase extraction and high performance liquid chromatography, has been developed to determine the concentration of 2-furfural the most stable compound in oil. The degradation of paper is being examined in order to find correlation between the change in dielectric and mechanical properties and the increase in concentration of 2-furfural in the oil.

On the Behavior of [Zn(Propyltetrazole)6](BF4)2 Single Crystal Under High-Vacuum Conditions

We studied the long-term (190 hours) behaviour of [Zn(propyltetrazole)6](BF4)2 single crystal under high-vacuum (HV) conditions (10−8 torr) with a depth-sensitive technique of positron annihilation spectroscopy (PAS). The obtained data indicate the slow formation of a new near-surface structure which is formed by the decomposition of the [Zn(propyltetrazole)6]2+ ions. The assumption of such a decomposition process was confirmed by additional mass spectroscopic measurements.

Distribution of toxic and radiation components in air particulates

The concentrations of several toxic heavy metals and volatile organic compounds (VOCs) in various types of Hungarian fly-ash fine particulates were investigated by means of instrumental neutron activation analysis, X-ray fluorescence analysis and gas chromatography, coupled with mass spectrometry. Within a power station, particulate samples were taken from the boiler zone (BO), from the electrostatic dust filter chamber (FI) and from the flue-gas at the top of the stack (ST). Enrichment rates of the toxic metals both in FI and ST particulate fractions related to the BO concentrations were calculated to enable the temperature dependence on the adsorption of the toxic components to be studied. In addition, both the total amounts of the VOCs and their partial distributions in accordance with the number of carbon atoms were also studied in fly-ash particulates. From them, 31 organic species were identified and determined. Since Hungarian brown coals have high uranium and thorium contents, the specific radioactivities of the daughter isotopes of both the 232Th and 238U decay series were also measured and are discussed.