Temporal evolution of tellurium emission lines in a capillary dielectric barrier discharge after hydride generation

Abstract In the field of analytical chemistry, the dielectric barrier discharge (DBD) is a widely used tool for trace element detection. Due to the good optical accessibility of the plasma in most DBD devices, one way to detect elements is optical emission spectrometry. Moreover, by means of temporally resolved optical emission spectrometry, the periodicity of the DBD can be utilized in order to get insight into the evolution of the plasma emission. Serving as analyte, tellurium was introduced into a capillary DBD via hydride generation. Temporally resolved broad band spectra of the discharge were recorded with an ICCD-camera coupled to a spectrograph. This enables to simultaneously track the emission of several plasma species along the discharge cycle. The maximum emission signal from tellurium was significantly delayed to the emission of the discharge gas helium and the hydrogen background. By means of the recorded broad band spectra it was shown that the ratio of two selected tellurium lines changed during the discharge cycle, which also resulted in different signal to noise ratios for both lines. The knowledge of the point in time at which optimal conditions for the signal to background ratio was achieved enabled to record a clear spectrum of the tellurium lines without additional background subtraction.