The present invention discloses an ionization apparatus 10 for ionizing an analyte S, comprising an inlet E, an outlet A, a first electrode 1, a second electrode 2 and a dielectric element 3. The first electrode 1, the second electrode 2 and the dielectric element 3 are arranged relative to one another such that, by applying an electric voltage between the first electrode 1 and the second electrode 2, a dielectric barrier discharge is establishable in a discharge area 5 in the ionization apparatus 10. The first and second electrodes 1, 2 are arranged such that they are displaceable or movable relative to each other.