In one implementation, processes for designing mass separators from a series of mass separator electric field data and processes for designing an ion trap from a range of data pairs and a mass analyzer scale are provided. Methods for producing mass separators including ion traps having Z.sub.0/r.sub.0 ratios from about 0.84 to about 1.2 are also provided. Mass spectrometers are also provided that can include mass separators in tandem with one being an ion trap having a Z.sub.0/r.sub.0 ratio between 0.84 and 1.2. The present invention also provides methods for analyzing samples using mass separators having first and second sets of components defining a volume with a ratio of a distance from the center of the volume to a surface of the first component to a distance from the center of the volume to a surface of the second component being between 0.84 and 1.2.