High-intensity, spiked noise is reduced in chromatography-mass spectrometry data by applying a nonlinear filter such as a moving median filter to the data. The method includes the following steps: vacuuming a hollow metal casing through a first open end thereof until an interior of the casing reaches a predetermined vacuum degree; sealing the first open end; filling a predetermined quantity of working fluid into the casing through a second open end thereof; and sealing the second open end. , or that can be integrated into the environment.