Quadrupole mass analyzers (QMA) are the most common type of instruments for the measurement of partial pressures of residual gases in semiconductor industry. The maximum range of this instrument available today is 1–1000 amu, which is equivalent to charge‐to‐mass ratios (Q/m) of 108–105 C/kg. Here, we report in detail the design, construction, and testing of a QMA capable of measuring (Q/m) ratios down to 5 C/kg. This instrument has been used to measure the Q/m distribution of ions, clusters, and microdroplets emitted from a needle‐tip type liquid metal ion source (LMIS). The Q/m distribution of clusters and microdroplets has been found to form a broad peak, and is concentrated mainly between 105 and 103 C/kg. The variation of this distribution as a function of total beam current and beam emission angle has been studied.