A non-destructive method for detecting charged particles, includes measuring a reference value of at least one physical parameter of an ion cloud confined in an ion trap; performing an injection of a sample in the ion cloud confined in the ion trap, the sample crossing the ion cloud and getting out the ion cloud without being trapped inside the ion trap; measuring a first experimental value of the at least one physical parameter of the ion cloud; and comparing the first experimental value with the reference value in order to determine the presence of at least one charged particle in the sample, or the absence of any charged particle in the sample.