Soft chemical ionization mass spectrometry techniques, particularly the well-established proton transfer reaction mass spectrometry, PTR-MS, and selected ion flow tube mass spectrometry, SIFT-MS, are widely used for real-time quantification of volatile organic compounds in ambient air and exhaled breath with applications ranging from environmental science to medicine. The most common reagent ions H3O+, NO+, or O2+• can be selected either by quadrupole mass filtering from a discharge ion source, which is relatively inefficient, or by switching the gas/vapor in the ion source, which is relatively slow. The chosen reagent ions are introduced into a flow tube or flow-drift tube reactor where they react with analyte molecules in sample gas. This article describes a new electrostatic reagent ion switching, ERIS, technique by which H3O+, NO+, and O2+• reagent ions, produced simultaneously in three separate gas discharges, can be purified in post-discharge source drift tubes, switched rapidly, and selected for transport into a flow-drift tube reactor. The construction of the device and the ion-molecule chemistry exploited to purify the individual reagent ions are described. The speed and sensitivity of ERIS coupled to a selected ion flow-drift tube mass spectrometry, SIFDT-MS, is demonstrated by the simultaneous quantification of methanol with H3O+, acetone with NO+, and dimethyl sulfide with O2+• reagent ions in single breath exhalations. The present ERIS approach is shown to be preferable to the previously used quadrupole filtering, as it increases analytical sensitivity of the SIFDT-MS instrument while reducing its size and the required number of vacuum pumps.
- MeSH
- dechové testy * MeSH
- hmotnostní spektrometrie přístrojové vybavení MeSH
- indikátory a reagencie analýza MeSH
- ionty analýza MeSH
- kyslík analýza MeSH
- lidé MeSH
- oniové sloučeniny analýza MeSH
- oxid dusnatý analýza MeSH
- plyny chemie MeSH
- statická elektřina MeSH
- tělesné tekutiny chemie MeSH
- vzduch MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- hydronium ion MeSH Prohlížeč
- indikátory a reagencie MeSH
- ionty MeSH
- kyslík MeSH
- oniové sloučeniny MeSH
- oxid dusnatý MeSH
- plyny MeSH
Vapor phase hydrogen peroxide (VPHP) nowadays finds more and more applications especially as a bio-decontamination agent for enclosed areas. Although this oxidizing agent logically offers a potential for the degradation of hazardous chemical contaminants, the information on the utilization within this area is very limited. The main objective of this study was to examine in detail the influence of basic operational (temperature, concentration of VPHP, relative humidity, condensation) and other conditions (e.g. amount of contaminant, the effect of UV radiation) on the efficiency of the VPHP process for the degradation of the selected model substance, i.e. 4-(dimethylamino)benzaldehyde. For this purpose, a series of different VPHP "wet" decontamination cycles (with a visible condensation) were carried out and compared. The obtained results clearly proved that VPHP could be utilized for the degradation of 4-(dimethylamino)benzaldehyde, however it was necessary to regard this process as a multi-parametric, in which all operational conditions played significant roles, while the molecular distribution of H(2)O and H(2)O(2) at first constituted the key factor for a successful degradation of contaminants on the surface. In order to achieve the highest decomposition efficiency of 4-(dimethylamino)benzaldehyde by the wet VPHP process, it appeared to be necessary to decrease the initial relative humidity in the relevant enclosed area (ideally up to 5%) before the introduction of VPHP and carry out this decontamination procedure ideally at 25°C and maintain the VPHP concentration higher than 500 ppm. Furthermore, it was found that the addition of UV radiation had a positive role on VPHP efficiency (in the best case, the degradation rate increased up to 1.5 times compared to using the sole VPHP). The monitoring of the concentration of VPHP within an enclosed facility is a good tool for the monitoring of the degradation of chemical contaminants by this agent.
- MeSH
- benzaldehydy analýza chemie MeSH
- chemické modely MeSH
- indikátory a reagencie analýza chemie MeSH
- látky znečišťující životní prostředí analýza chemie MeSH
- peroxid vodíku chemie MeSH
- regenerace a remediace životního prostředí metody MeSH
- teplota MeSH
- změna skupenství MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- benzaldehydy MeSH
- indikátory a reagencie MeSH
- látky znečišťující životní prostředí MeSH
- p-dimethylaminobenzaldehyde MeSH Prohlížeč
- peroxid vodíku MeSH
An electrochemical DNA biosensor based on the screen printed carbon paste electrode (SPCPE) with an immobilized layer of calf thymus double-stranded DNA has been used for in vitro investigation of the interaction between genotoxic nitro derivatives of fluorene (namely 2-nitrofluorene and 2,7-dinitrofluorene) and DNA. Two types of DNA damage have been detected at the DNA/SPCPE biosensor: first, that caused by direct association of the nitrofluorenes, for which an intercalation association has been found using the known DNA intercalators [Cu(phen)(2)](2+) and [Co(phen)(3)](3+) as competing agents, and, second, that caused by short-lived radicals generated by electrochemical reduction of the nitro group (observable under specific conditions only).
- MeSH
- biosenzitivní techniky * MeSH
- DNA analýza chemie MeSH
- elektrochemie * MeSH
- fluoreny farmakologie MeSH
- indikátory a reagencie analýza chemie MeSH
- poškození DNA genetika MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- 2,7-dinitrofluorene MeSH Prohlížeč
- calf thymus DNA MeSH Prohlížeč
- DNA MeSH
- fluoreny MeSH
- indikátory a reagencie MeSH
We describe here a newly developed method for a contact-free optical pH measurement in yeast suspensions supplemented with glucose, and containing the pH sensitive triphenylmethane dye bromocresol green. It is suitable for performing the acidification power test (based on measuring the rate of pH drop of yeast suspension caused by active extrusion of acidity from cells after glucose addition) used for assessing yeast vitality in fermentation industries. Using this methodology we monitored the pH in yeast suspensions in the course of acidification in the pH range of 3.5-5.3. Optical pH measurement allows simultaneous testing of several samples, minimizes the sample volume, simplifies sample handling and reduces the hands-on time in sample processing.
- MeSH
- bromkresolová zeleň analýza MeSH
- fermentace MeSH
- glukosa metabolismus MeSH
- indikátory a reagencie analýza MeSH
- kolorimetrie přístrojové vybavení metody MeSH
- koncentrace vodíkových iontů * MeSH
- kultivační média speciální chemie MeSH
- kvasinky metabolismus MeSH
- mykologie přístrojové vybavení metody MeSH
- nefelometrie a turbidimetrie přístrojové vybavení metody MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- bromkresolová zeleň MeSH
- glukosa MeSH
- indikátory a reagencie MeSH
- kultivační média speciální MeSH
- MeSH
- chromatografie na tenké vrstvě MeSH
- indikátory a reagencie analýza MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- indikátory a reagencie MeSH
- MeSH
- aminokyseliny analýza MeSH
- dieta aterogenní MeSH
- fyziologická adaptace * MeSH
- fyziologický stres MeSH
- indikátory a reagencie analýza MeSH
- játra analýza MeSH
- krysa rodu Rattus MeSH
- myokard analýza MeSH
- peptidy analýza MeSH
- svaly analýza MeSH
- terapeutická hypotermie * MeSH
- tkáňové extrakty analýza MeSH
- zvířata MeSH
- Check Tag
- krysa rodu Rattus MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- aminokyseliny MeSH
- indikátory a reagencie MeSH
- peptidy MeSH
- tkáňové extrakty MeSH
- MeSH
- aklimatizace * MeSH
- elektroforéza MeSH
- indikátory a reagencie analýza MeSH
- krysa rodu Rattus MeSH
- metody MeSH
- myokard analýza MeSH
- nadmořská výška MeSH
- proteiny metabolismus MeSH
- svaly analýza MeSH
- vystavení vlivu životního prostředí MeSH
- zvířata MeSH
- Check Tag
- krysa rodu Rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- indikátory a reagencie MeSH
- proteiny MeSH
