SDIFA mass spectrometry
AssigneeCleveland State University
InventorsBaochuan Guo, Shenyi Wang
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Abstract
The mass resolution and accuracy of delayed extraction matrix assisted desorption/ionization time of flight mass spectrometry is improved by spatially separating the electric field used for driving extraction/acceleration from the sample being analyzed.
Claims32
A mass spectrometer for carrying out desorption-ionization time-of-flight mass spectrometry in which a detector senses ions produced by pulsed ionization and desorption of a sample, wherein the mass spectrometer includes a first focusing element and a power source capable of elevating the electrical potential of the first focusing element to a higher electrical potential than the sample a predetermined time after pulsed ionization and desorption thereby creating (a) a rejection electrical field preventing a first portion of the ions from reaching the detector and (b) an acceleration electric field accelerating a second portion of the ions towards the detector.
A mass spectrometer for carrying out desorption-ionization time-of-flight mass spectrometry in which pulsed ionization of a sample creates a plume of ions which expands towards a detector, wherein the mass spectrometer includes
- a first focusing element,
- a second focusing element maintained at essentially the same electrical potential as the sample,
- a power system for applying a pulse of increased electrical potential to the first focusing element, and
- a control system for triggering the power system so that, when a pulse of increased electrical potential is applied to the first focusing element, the ion plume is divided by the first and second focusing elements into a region of slow moving ions, a region of fast moving ions and a region of intermediate velocity ions, wherein the slow moving ions are prevented from reaching the detector at all while the fast moving ions reach the detector only as background noise.
A process for enhancing the resolution of a desorption-ionization time-of-flight mass spectrometer comprising applying an increased electrical potential to a first focusing element spaced apart from the sample being analyzed after a substantial portion of the ion plume created by sample ionization passes the first focusing element towards the detector of the spectrometer, the increased electrical potential being greater than the electrical potential of the sample so that ions of the plume not having reached the first focusing element when the increased electrical potential is applied are prevented from passing the first focusing element by the increased electrical potential.
A process for enhancing the resolution of a desorption-ionization time-of-flight mass spectrometer comprising preventing a portion of the ions produced by sample ionization from reaching the detector of the spectrometer by applying a first electrical potential to a first focusing element spaced apart from the sample being analyzed, the first electrical potential being greater than the electrical potential of the sample.
Dependencies are inferred from the claim text.