This paper will discuss the design and evaluation of a mass spectrometer filament modified to lower the thermionic work function (the amount of energy required to move electrons from the Fermi energy level into vacuum) for electron emission. This in turn lowers the required operating temperature, resulting in increased operational lifetime by reducing (1) thermal shock during filament heating and sample elution, (2) physical filament distortion caused by reannealing and crystal boundary migration, and (3) the rate of metal evaporation. The modification increases inertness towards certain compounds detrimental to filament function (e.g. oxygen, water, solvents, and certain analytes), also extending functional filament lifetime.
This new filament design will be tested on a production quadruple bench-top GC/MS(Gas Chromatograph/Mass Spectrometer). Results will be presented discussing filament lifetime when used with various solvents, samples, and sample injection techniques. This new filament design will enable GC/MS users to extend the time between required system maintenance, and have lower overall operating costs.
All funding for this work was supplied by PerkinElmer Life and Analytical Sciences.
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