system in which an electrically operated solenoid valve is used to control the injection of sample into the inlet port although there are a variety of simple flaps that may be employed to temporarily close the inlet port it is also possible for the operator to simply place his finger directly over the inlet port 405 the capillary inlet line for the mass spectrometer sampling system will have an internal diameter of less than 1 mm so it is possible for the operator to place virtually any object over the inlet to effectuate a workable seal including a simple bare finger or a finger covered with a piece of plastic tubing or tape in order to prevent any possible contamination produced by the operator 39 s skin itself in addition to the embodiments described there are many additional configurations of a mass spectrometer sampling system that may be employed although a mechanical vacuum pump is shown in fig1 fig2 and fig3 as a separate module connected to the mass spectrometer manifold it is also possible for a small turbomolecular pump to be installed in the mass spectrometer manifold itself with a small roughing pump attached externally to the mass spectrometer manifold another embodiment of the sampling system would comprise a capture pump such as an ion pump a cryopump or a getter pump installed within the mass spectrometer manifold itself with a roughing pump attached externally to the mass spectrometer manifold in another embodiment the sampling system could be used with a portable mass spectrometer that contains a capture pump but does not have a roughing pump installed instead the portable mass spectrometer is periodically.