Patent ID: RE40632

Claim:
A mass spectrometer system including a mass analyzer disposed in a high vacuum chamber for analyzing sample ions formed at atmospheric pressure and directed to the analyzer through intermediate vacuum chambers in which sample ions and solvent molecules form adduct ions with a reduction of sample ion current including: first and second evacuated chambers directly preceding the mass analyzer chamber with the first chamber being at a higher pressure than the second chamber, a first multipole ion guide in the first chamber for guiding ions into said second chamber, a second multipole ion guide in the second chamber for guiding ions from the first chamber into the high vacuum chamber for mass analysis, and means associated with one or both of said first and second multipole ion guides for increasing the translational kinetic energy of the adduct ions so that at the vacuum pressure of the second interface chamber adduct ions traveling into the chamber are converted into sample ions without fragmentation of sample ions whereby to increase the sample ion current and therefore the sensitivity of the mass spectrometer system.