München 2019 – wissenschaftliches Programm
P 11.3: Vortrag
Dienstag, 19. März 2019, 14:45–15:00, HS 21
Detection and quantification of arsenic in a dielectric barrier discharge with spatial and temporal resolution — •Sebastian Burhenn1, Jan Kratzer2, Antje Michels1, and Joachim Franzke1 — 1Leibniz Institut für Analytische Wissenschaften - ISAS - e.V., Bunsen-Kirchhoff-Str. 11, 44139 Dortmund, Germany — 2Czech Academy of Sciences, Institute of Analytical Chemistry, Veveří 97, CZ-602 00 Brno, Czech Republic
Due to their versatility, plasmas enjoy high popularity in the field of analytical chemistry. In particular, for the detection and quantification of elements, several different plasma based approaches such as inductively coupled plasma mass spectrometry (ICP-MS) became standard. Since the operation of the ICP is related to high costs, dielectric barrier discharges (DBDs) have proven to be a simple and cost effective alternative, achieving excellent detection limits. However, the mechanisms for the atomization and excitation of the analyte in the plasma are not yet fully understood. In this work the emission signal of the model analyte arsenic, which is introduced into a capillary DBD via hydride generation is tracked with spatial and temporal resolved optical emission spectrometry (OES). The plasma inside the capillary DBD is mapped through a monochromator to the CCD of an iCCD-camera serving as a detector with a temporal resolution of 5 ns. It was shown that the emission of arsenic atoms at the 234 nm line is delayed to the emission of the background signal. This enables to temporally separate the analyte signal from the background, which enhances the signal to noise ratio and results in a low detection limit of 93 ppt.