Multiple ionization ion sources and multiple mass analyzers are combined into one mass spectrometer instrument by a six-electrodes ion trap or an array of six-electrodes ion traps. The six-electrodes ion trap can be operated as an independent two-dimensional ion guide or linear ion tap in an arbitrarily selected direction among three orthogonal XYZ directions. The two-dimensional ion guide/linear ion trap can be alternated from one direction to another among the three orthogonal directions electrically. A six-electrodes ion trap generates six equivalent importing and exporting interfaces, each of the interfaces can be used to trap external ions and transfer the trapped ions to any of the other five interfaces. The six-electrodes ion trap provide a mass spectrometer with versatility, multiply functions, high duty-cycles and high sample throughput.