How to Repair IG Tungsten Filament of GC-MS?

One of the most important methods to analyze the structural of organic compound is organicmass spectrometry (OMS), thanks to its fast speed, accurate property and molecular weight and other excellent features, OMS can directly analyze formula weight and structure of various organic compounds of a mixture. Mass spectrometry is an analytical method to measure the proportion of ion charge (the charge - mass ratio) which is a plot of the ion signal as a function of the mass-to-charge ratio. These spectra are used to determine the elemental or isotopic signature of a sample, the masses of particles and of molecules, and to elucidate the chemical structures of molecules, such as peptides and other chemical compounds. Therefore, gas chromatography - mass spectrometry (GC-MS) has been widely used in organic chemistry, organic geochemistry, biochemistry, food chemical, petrochemical, medical and health, environmental science and other fields. HP5890-5971 GC-MS is a high-performance analytical instrument. In normal using, the life time of ion gun wolfram filament can last for one year or longer. However, if the sample was not handled adequately, moisture content is too high, or injection quantity is too much which will greatly shorten the life time of the IG tungsten filament. If use the imported filament, then frequent replacement would cause greater economic losses and burdens. Thus, repair the IG tungsten filament of GC-MS can not only reduce costs, but also extend the life time of the filament which plays a role in protecting the environment.

First of all, cleaning the filament frame. Material should be cleaned with absolute methanol as the solvent, in the condition of ultrasound cleaning it for 5 minutes, then drying it at the temperature of 105 ℃. The next step is to wash the directly heated cathode. Oil should be cleaned with phosphoric acid cleaning agent, then rinse it with water, ultrasound cleaning it with absolute methanol for 3 minutes and finally drying it at a temperature of 105 ℃. The third step is to anneal the filaments. The fourth step is spot welding which is a high-speed, economical connection method. The final step is to clean the frame of electron-tube heater again, washing the excess flux.

Its relative abundance, quality and abundance are similar with the original filaments by this method to repair an ion source W-filament. 

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