Free carbon nanopearl layer cathodes have already proved to be good emitters under poor vacuum conditions. In order to improve the cathode reliability and the cost of fabrication, a new design of nanopearl field emitter has been developed wherein the nanopearls are suspended and protected in a polymer matrix. A polymer embedded carbon nanopearl field emitter of this design has been developed and operated as the ionization source in a commercial time of flight mass spectrometer (TOF-MS) system. Systematic analyses of the effect of acetophenone and 2-nitrotoluene (at pressures of similar to 10(-5) Torr) on cold cathode behavior inside the TOF-MS have been carried out and results from these studies show that electron emission is not adversely affected. (c) 2008 American Vacuum Society.