Systems and methods for analyzing samples are provided. In some embodiments, a mass spectrometer may include a source configured to output one or more ions, a plurality of chambers having different pressures, a detector configured to detect the one or more ions, and a particle guide. The plurality of chambers may include at least a first chamber having a first pressure that is less than atmospheric pressure and a second chamber having a second pressure that is less than the first pressure. In some embodiments, the particle guide may include a conduit through which the one or more ions may travel an entire length of the particle guide. The conduit may be disposed within at least the first chamber and the second chamber, and vents may be disposed to define passages between the chambers and the conduit.