Systems and methods for reducing background noise in a mass spectrum. The method includes the following steps of: (a) obtaining an original mass spectrum; (b) determining a noise mass spectrum corresponding to background noise in the original mass spectrum; and (c) determining a corrected mass spectrum by subtracting the noise mass spectrum from the original mass spectrum. Step (b) of the method may include the steps of: A) effecting a transformation of the original mass spectrum into the frequency domain to obtain an original frequency spectrum; B) identifying at least one dominant frequency in the original frequency spectrum; C) generating a noise frequency spectrum by selectively filtering for said dominant frequencies; and D) determining the noise mass spectrum by effecting a transformation of the noise frequency spectrum into the mass domain. Preferably for each correlated pair of original and noise intensity data points, the minimum value is determined and the noise mass spectrum is modified by making the noise intensity data point equal to the minimum value.