A miniature plasma source based on dielectric barrier discharge (DBD) can be used for direct analysis of different substances in solid form. The ionisation source is installed in front of the inlet of a mass spectrometer with micromanipulators enabling a precise alignment.

The dielectric barrier discharge is generated in helium by applying a sinusoidal voltage with a frequency of 27 kilohertz and an amplitude of 7 kilovolts to two electrodes attached on a fused silica tube. The oscillator circuitry is based on an oscillator and a high voltage transformer.

Different examples from food analysis, pharmaceuticals and illegal drugs are given employing DBD as a soft ionization technique.

(A) cinnamaldehyde in cinnamon powder, (B) loratidine as active component in Claritin^® tablets, (C) morphine, codeine and 6-acetylmorphine in an opiate mixture (D) piperine in powdered pepper.