A miniature quadrupole mass spectrometer array consisting of 16 rods in a 4×4 array is reported. Each rod is 25 mm in length and 2 mm in diameter. The ionizer is of a miniature Nier-type design, and the detector is a channel-type electron multiplier. Operating frequencies are 5.3, 7.1, and 12.9 MHz. The mass range demonstrated herein is 1–300 u; and the resolution of the system is 0.1–0.5 u (full width at half-maximum), orm/&Dgr;m=600. The present sensitivity is calculated and measured to be approximately1×1012counts/Torr s. ©1997 American Institute of Physics.