Ion extraction devices, mass spectrometer devices, and methods of selectively extracting ions and performing mass spectrometry

An ion extraction device comprising:

• a gas cell in which a supply of ions in a body of gas can be located;
• means for generating a ponderomotive ion trapping potential generally along an axis;
• means for generating further potentials to provide an effective potential which prevents ions from being extracted from an extraction region;
• the device being configured so that the characteristics of the effective potential which prevent ions from being extracted from the extraction region are caused, at least in part, by the generation of the ponderomotive ion trapping potential;
• and
• ion extraction means for selectively extracting ions of a predetermined m/z ratio or ion mobility from the extraction region.

A mass spectrometer device including:

• a mass selective or ion mobility selective ion trap;
• a mass scanning mass spectrometer located downstream of the ion trap so that ions ejected from the ion trap are directed into the mass scanning mass spectrometer;
• means for generating a ponderomotive ion trapping potential generally along an axis;
• means for generating further potentials to provide an effective potential which prevents ions from being extracted from an extraction region;
• the device being configured so that the characteristics of the effective potential which prevent ions from being extracted from the extraction region are caused, at least in part, by the generation of the ponderomotive ion trapping potential;
• and
• control means for:
• i) sequentially and selectively ejecting ions from the ion trap according to the mass to charge ratio or the ion mobility of the ions;
• (ii) scanning the mass of the ions transmitted by the mass scanning mass spectrometer;
• and (iii) synchronising (i) and (ii) so that the mass of at least some of the ions directed into the mass scanning mass spectrometer corresponds to the mass of the ions transmitted by the mass scanning mass spectrometer thereby enhancing the sensitivity of the mass scanning mass spectrometer.

A method of performing mass spectrometry including:

• sequentially and selectively ejecting ions from a mass selective or ion mobility selective ion trap according to the mass to charge ratio or the ion mobility of the ions generating a ponderomotive ion trapping potential generally along an axis;
• generating further potentials to provide an effective potential which prevents ions from being extracted from an extraction region, in which the characteristics of the effective potential which prevent ions from being extracted from the extraction region are caused, at least in part, by the generation of the ponderomotive ion trapping potential;
• directing the ejected ions to a mass scanning mass spectrometer;
• and
• scanning the mass of the ions transmitted by the mass scanning mass spectrometer;
• in which the ejection of the ions from the ion trap and the scanning of the mass scanning mass spectrometer are synchronised so that the mass of at least some of the ions directed into the mass scanning mass spectrometer corresponds to the mass of the ions transmitted by the mass scanning mass spectrometer thereby enhancing the sensitivity of the mass scanning mass spectrometer.