Atomization of hydrides and their methylated analogues in a dielectric barrier discharge (DBD) plasma atomizer was investigated. Selected ion flow tube mass spectrometry (SIFT-MS) was chosen as a detector being capable of selective detection of non-atomized original volatile species allowing thus direct quantification of atomization efficiency. Selenium hydride (SeH2) and three volatile arsenic species, namely arsenic hydride (AsH3), monomethylarsane (CH3AsH2) and dimethylarsane ((CH3)2AsH), were selected as model analytes. The mechanistic study performed contributes to understanding of the atomization processes in atomic absorption spectrometry (AAS). The presented results are compatible with a complete atomization of arsenic hydride as well as its methylated analogues and with atomization efficiency of SeH2 below 80%. Using AsH3 as a model analyte and a combination of AAS and SIFT-MS detectors has revealed that the hydride is not atomized, but decomposed in the DBD atomizer in absence of hydrogen fraction in the carrier gas. Apart from investigation of analyte atomization, the SIFT-MS detector is capable of quantitative determination of water vapor content being either transported to, or produced in the atomizer. This information is crucial especially in the case of the low-power/temperature DBD atomizer since its performance is sensitive to the amount of water vapor introduced into the plasma.

• MeSH
• arsen * MeSH
• hmotnostní spektrometrie MeSH
• nebulizátory a vaporizátory MeSH
• spektrofotometrie atomová MeSH
• vodík MeSH
• Publikační typ
• časopisecké články MeSH

A slurry sampling procedure for arsenic speciation analysis in baby food by arsane generation, cryogenic trapping and detection with atomic absorption spectrometry is presented. Several procedures were tested for slurry preparation, including different reagents (HNO3, HCl and tetramethylammonium hydroxide - TMAH) and their concentrations, water bath heating and ultrasound-assisted agitation. The best results for inorganic arsenic (iAs) and dimethylarsinate (DMA) were reached when using 3molL-1 HCl under heating and ultrasound-assisted agitation. The developed method was applied for the analysis of five porridge powder and six baby meal samples. The trueness of the method was checked with a certified reference material (CRM) of total arsenic (tAs), iAs and DMA in rice (ERM-BC211). Arsenic recoveries (mass balance) for all samples and CRM were performed by the determination of the tAs by inductively coupled plasma mass spectrometry (ICP-MS) after microwave-assisted digestion and its comparison against the sum of the results from the speciation analysis. The relative limits of detection were 0.44, 0.24 and 0.16µgkg-1 for iAs, methylarsonate and DMA, respectively. The concentrations of the most toxic arsenic species (iAs) in the analyzed baby food samples ranged between 4.2 and 99µgkg-1 which were below the limits of 300, 200 and 100µgkg-1 set by the Brazilian, Chinese and European legislation, respectively.

• MeSH
• analýza potravin přístrojové vybavení   metody   MeSH
• arsen analýza   MeSH
• arsenikové přípravky analýza   MeSH
• design vybavení MeSH
• kojenec MeSH
• kontaminace potravin analýza   MeSH
• kyselina kakodylová analýza   MeSH
• lidé MeSH
• mikrovlny MeSH
• novorozenec MeSH
• potrava pro kojence analýza   MeSH
• rýže (rod) chemie   MeSH
• spektrofotometrie atomová přístrojové vybavení   metody   MeSH
• vibrace ultrazvukové přístrojové vybavení   metody   MeSH
• Check Tag
• kojenec MeSH
• lidé MeSH
• novorozenec MeSH
• Publikační typ
• časopisecké články MeSH

The aim of this study was to compare two methods for quantification of changes in intracellular potassium concentration (decrease from ∼140 to ∼20mM) due to the action of a pore-forming toxin, the adenylate cyclase toxin (CyaA) from the pathogenic bacterium Bordetella pertussis. CyaA was incubated with stably transfected K1 Chinese hamster ovary cells expressing the toxin receptor CD11b/CD18 and the decrease in potassium concentration in the cells was followed by inductively coupled plasma mass spectrometry (ICP-MS). It is shown that this method is superior in terms of sensitivity, accuracy, and temporal resolution over the method employing the potassium-binding benzofuran isophthalate-acetoxymethyl ester fluorescent indicator. The ICP-MS procedure was found to be a reliable and straightforward analytical approach enabling kinetic studies of CyaA action at physiologically relevant toxin concentrations (<1000ng/ml) in biological microsamples.

• MeSH
• adenylátcyklasový toxin toxicita   MeSH
• antigeny CD11b genetika   MeSH
• antigeny CD18 genetika   MeSH
• Bordetella pertussis enzymologie   MeSH
• CHO buňky MeSH
• Cricetulus MeSH
• draslík chemie   metabolismus   MeSH
• fluorescenční barviva chemie   MeSH
• hmotnostní spektrometrie metody   MeSH
• intracelulární prostor účinky léků   metabolismus   MeSH
• křečci praví MeSH
• lidé MeSH
• transfekce MeSH
• zvířata MeSH
• Check Tag
• křečci praví MeSH
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

• Klíčová slova
• management, řízení práce,
• MeSH
• organizace a řízení MeSH

• Klíčová slova
• management,
• MeSH
• hodnocení rizik MeSH
• organizace a řízení MeSH
• podnikání MeSH
• řešení problému MeSH
• rozhodování organizační MeSH
• Publikační typ
• příručky MeSH

• Konspekt
• Management. Řízení

• Klíčová slova
• spektrometrie atomová absorbční,

• Konspekt
• Biochemie. Molekulární biologie. Biofyzika
• NLK Obory
• fyzika, biofyzika
• chemie, klinická chemie