[seminar] seminar na IF-u, 15. rujna 2011. u 15:00h

[Vlasta Horvatic]

      Institut za fiziku, Bijenicka cesta 46,

      predavaonica u zgradi Mladen Paic

      cetvrtak, 15. rujna 2011. u 15:00 sati
     
      Detection of dissolved metals using a liquid electrode 

      dielectric barrier discharge (LE-DBD)

       

      and

       

      Characterization of a DBD plasma jet for soft ionization
     
      Tobias Krähling, MSc 

      and

      Saskia Müller, MSc
     
      Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V., Dortmund, Germany

      E-mail:  saskia.mueller at isas.de , Tobias.Kraehling at isas.de
     
      Analysis of dissolved metals in liquid samples using a dielectric barrier discharge with flowing liquid electrode has been studied. Inside a fused silica capillary the discharge is ignited between the liquid surface and a tungsten electrode, driven by a pulsed high voltage. In this manner the flowing liquid acts as second electrode itself and the wall of the capillary as dielectric barrier. Due to a pulsation of the electrode gap the discharge is sustainable for one hour and more. Calibration measurements are performed for several alkali, alkaline earth metals and silver. With a flow rate of 20 µL/min detection limits between 0.02 mg/L for potassium and 6.9 mg/L for barium are determined. Application as metal detection system for environmental liquid samples as well as monitoring device in flow systems seems possible.

       

      ~~~~~~~~~~~~~~~~~~~~~~

      A source for soft ionization of organic molecules will be presented. It is based on an atmospheric pressure dielectric barrier plasma jet, whereby the plasma is ignited inside a glass capillary surrounded by two ring electrodes. The length of the plasma jet depends on the applied gas and the gas flow. Pure He, Ne and Ar are used as operating gases. To characterize the mechanisms, which are responsible for soft ionization, spatially resolved optical emission spectrometry (OES) measurements were implemented. Besides on the emission of the different element lines, a special focus was put also on the intensity variation of the N2 and N2+ lines, which are involved in the ionization process.

       

      http://www.isas.de/Projects.79.0.html
     
       

      Voditelji seminara IF-a: Vlasta Horvatic i Ivica Zivkovic
     
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