Abstract: The present invention discloses a gas chromatograph assembly. In one implementation, the assembly includes a sample injector and a guard column assembly. The guard column assembly includes a guard column connected to and downstream of the sample injector; a jacket with low thermal mass surrounding the guard column; a temperature controlled heater connected to the jacket to control the temperature of the jacket and thereby the temperature of the guard column; and an insulating housing surrounding the jacket. An analytical column is connected to and downstream of the guard column.

Abstract: The present invention relates to a mass spectrometer, and more specifically a portable mass spectrometer. In one implementation, the mass spectrometer includes a toroidal transformer. In another implementation, the mass spectrometer includes feedback circuitry to monitor signals applied in the mass spectrometer.