Switchable Reagent Ions

and 2 was developed with sensitivities of up to 800 cps/ppbv for aromatics, aldehydes, and ketones and this instrument has been denoted as PTR-SRI-MS [61], The HjO source in this instrument was again water vapor, the source gas for NO was ambient air that is passed through a charcoal filter and the source gas for 02 was pure O2. The switching time in the PTR-SRI-MS instrument between reagent ions is around 10 s which when combined with the drift field does not allow the same separation of isobaric ions that are found using SIFT-MS instruments. 

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Jordan A, Haidacher S, Hanel G, Hartungen E, Herbig J, Maerk L, Sehottkowsky R, See-hauser H, Sulzer P, Maerk TD. An online ultra-high sensitivity proton-transfer-reaction mass-spectrometer combined with switchable reagent ion eapabilily (PTR + SRI-MS). Int J Mass Speetrom. 2009 286 32-8. 

In a follow-up study by the same research group, this methodology was used to investigate the effects of different pig rearing systems on the quality of the final product of dry-cured Iberian ham. In this work, a switchable reagent ion source was used to generate H3O +,... 

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