An adjustable, low mass-to-charge (m/z) filter has been developed and demonstrated using electrospray ionization to block ions associated with unwanted low m/z species from entering the mass spectrometer and contributing their space charge to down-stream ion accumulation steps. This technology can be used alone or in conjunction with other established methods that lessen the detrimental effects of excessive space charge in order to improve data quality. We show that implementing the low-m/z filter in an electrodynamic ion funnel provides a linear voltage adjustment of low-mass filtering from m/z 50 to 500. The mass filter was evaluated with a liquid chromatography-mass spectrometry analysis of an albumin tryptic digest and resulted in the ability to block low-mass, “background” ions which account for 40-70% of the total ion current from the ESI source during peak elution. This technology can also be used in any applications where lower m/z ions need to be prohibited from entering the instrument. The ion funnel mass filter device is easily implemented, independent of the type of instrument, and contained solely in the source eliminating the need to change any elements or potentials in the mass spectrometer. Additionally, the ability to simply set the maximum m/z cut-off of the filter allows for the tailoring of the device to better match the m/z range requirements of various samples.