Profile: ESI Source Solutions offers active background ion reduction device (ABIRD) for nanospray ESI sources. The ABIRD protects the mass spectrometer from variable ambient laboratory air with no loss of ion signal. It isolates the mass spectrometer from transient sources of background ions in the lab. It protects the instrument from ambient spikes in laboratory air quality. It works with an open or semi-sealed ESI source. It uses inexpensive disposable cartridge filters. The ABIRD imparts to a mass spectrometry system a consistent low background ion signal with improved peak signal to noise ratios while isolating the instrument from variable ambient conditions in the laboratory with no loss of peptide signal.