Systems and methods are provided for performing multiplex electrostatic linear ion trap mass spectrometry. A first beam of ions is received and the first beam is split into N beams of ions using a beam splitter. N is two or more. Ions are received from only one of the N beams of ions at each entrance aperture of N entrance apertures of an electrostatic linear ion trap (ELIT). Ions from each entrance aperture of the N entrance apertures are trapped in separate linear flight paths using the ELIT, producing N separate linear flight paths. Ion oscillations in the N separate linear flight paths are measured at substantially the same time using the ELIT. The ELIT uses two concentric mirrors with N apertures to trap ions in the N separate linear flight paths. The ELIT uses an image current detector with N apertures to the measure the ion oscillations.