1978 Volume 26 Issue 2 Pages 171-185
It is considered that the memory of fect appears in a metallic gas inlet of a mass spectrometer for measurement with samples of BF3is classified into two kinds, one is essential memory of fect which is caused by an action between the surface of metal and BF3, and the other is additional memory effect which is caused by viscous liquid produced by reaction among water, BF3and metals. The additional memory effect is caused by stain on the inner surface of the gas inlet. Air is introduced into the sample bottle joint at each time for change of sample bottle. Moisture in the air is adsorbed on inner surfaces of the joint and piping made of metal, and combined with BF3which introduced, and then viscous compound is produced by dissolution of the metal into the compound made from H2O and BF3. The vapour pressure of the viscous compound not sufficient low, and so the compound propagates from the sample bottle joint to the whole of the gas inlet at each time of opening and closing of valves of the gas inlet. The coated film of the viscous compound with adsorption and release of BF3is cause of the additional memory effect. If the stain of the inner surface of the gas inlet grows up, the additional memory effect becomes more intense compared with the essential memory effect, and the measured values are not converged. To remove the additional memory effect, it is desirable to introduce the sample BF3after the moisture intruded into the piping by the exchange of sample bottles is removed sufficiently by introduction of F2or ClF3.
