Analytica of Branford, Inc.

Bruce Andrien

Craig M Whitehouse

Thomas Dresch

A Time-Of-Flight mass spectrometer is configured with a pulsing region and electronic controls to cause the directing of ions to a surface in the Time-Of-Flight pulsing region. The population of ions resulting from the collecting of said ions on or near said surface is subsequently accelerated into the Time-Of-Flight tube for mass to charge analysis. Ions produced away from said surface located in the pulsing region of a Time-Of-Flight mass spectrometer can be directed to the surface with high or low surface collisional energies. Higher energy ion collisions with the surface can result in Surface Induced Dissociation fragmentation and the resulting ion fragment population can be accelerated into Time-Of-Flight tube where the ions are mass to charge analyzed. Ion mass to charge selection can occur prior to directing ions to the pulsing region surface allowing MS/MS Time-Of-Flight mass analysis with SID. Ion to surface low energy collisions or soft landings resulting in little or no ion fragmentation provide a means for spatially focusing ions on or near the surface prior to accelerating the surface collected ions into the Time-Of-Flight tube. The apparatus and methods described in the invention result in refined control of ion fragmentation energy and improved Time-Of-Flight mass to charge analysis performance.

Mass spectrometry from surfaces

A Time-Of-Flight (TOF) mass analyzer is configured with a multipole ion guide in the ion path between the ion source and pulsing region of the mass analyzer, and enables trapping or transmission of ions from an atmospheric pressure ion source. The mass-to-charge (m/z) range(s) of ions transmitted through or trapped in the ion guide can be selected. Ions with stable trajectories can undergo Collisional Induced Dissociation (CID). During ion fragmentation, the ion guide potentials can be set to transmit or trap fragment ions produced by CID. The parent and fragment ion population can be delivered from the ion guide to the pulsing region of the TOF mass analyzer for mass analysis. After the first fragmentation step, the ion guide potentials can again be set to select a narrow m/z range to clear the ion guide in trapping mode of all but a selected set of fragment ions. M/z selection and ion fragmentation can be repeated a number of times with mass analysis occurring at the end of all the MS/MS.sup.n steps or at various times during the MS/MS.sup.n stepwise process. Additionally, the normally stepwise MS/MS.sup.n analysis function can be merged into a single step, increasing the effective duty cycle. In all embodiments, the ion guide can reside in one vacuum pumping stage or can extend continuously into more than one vacuum pumping stage.

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Branford, CT, United States of America

Bruce Andrien