External thermionic source

Qmdntpole Ion Trap with an External Thermionic Source By the use of mass-selective instabihty experiments, the ion trap mass spectrometer serves as both a reactor in which ion/molecule reactions occur, and a mass analyzer for the products of these reactions. The analytical use of ion trap mass spectrometers relies upon the method of ramping the radio frequency (RF) drive potential. The capabilities of ion traps to perform attachment reactions with alkali cations using classical scanning sequences have been exploited. Kinetic studies have shown that, the attachment efficiency is very high, near-collision efficiency, and illustrate how the present method is particularly well suited for ion trap mass spectrometers. Control of the attachment process may be readily performed by the use of a classical ionization sequence in some aspects similar to a tandem MS/MS scanning sequence. 

Sablier et al. performed all experiments using a Varian Saturn III GC/MS research ion trap mass spectrometer with a quadmpole ion trap mass spectrometer equipped with an external thermionic ion source to generate the reagent Na+ ions [86]. Samples were admitted into the ion trap either through a variable leak valve... 

Today s thermionic detectors are quite reliable and quantitative devices. A key to long-term stability and quantitative reproducibility seems to have been the utilization of an externally-heated alkali source [118]. The explanation of nitrogen detection based on the interaction of cyano radicals with the excited rubidium atoms [118] appears quite plausible, while the nature of response to phosphorus compounds still seems obscure. 

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