Berlin 2012 – scientific programme

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UP: Fachverband Umweltphysik

UP 9: Poster session

UP 9.20: Poster

Wednesday, March 28, 2012, 18:30–19:15, Poster F

Development of an active alkaline trap to determine acidic gas ratios in volcanic plumes: sampling technique and analytical methods — •Julian Wittmer¹, Nicole Bobrowski¹, Marcello Liotta², and Ulrich Platt¹ — ¹IUP Heidelberg, Germany — ²INGV Palermo, Italy

The study of the chemical interaction of volcanic gases with the atmosphere is an important issue to determine the volcanic gas composition when a diluted plume is sampled. Over the last years volcanic monitoring has been strongly influenced by optical measurement systems, whose development goes along with comparison to and is complemented by results of reliable and accurate direct sampling techniques. Besides Giggenbach bottles and filter packs, the alkaline trap is an established method to sample acid gas species.

The active alkaline trap, used in this work, is based on the principle of a Drechsel bottle to purify gas mixtures. A NaOH solution inside the bottle performs an acid-base reaction while the diluted volcanic gases are pumped through. To assess the concentration of the elements, the samples are analysed by titration and ion chromatography (IC). For higher sensitivity the analysis by IC-MS (IC coupled with mass spectrometry), ICP (Inductively coupled plasma)-MS and neutron activation is planned. The various methods will be compared and tested, using samples taken at Etna and Stromboli (Italy) in cooperation with the National Institute of Volcanology and Geophysics, Palermo, Italy. First results will be presented for the detection of carbon dioxide, sulphur, chlorine, fluorine, bromine and iodine.