New methods of operation and improvements in the instrumentation of tandem mass spectrometry
Abstract
A hybrid BEQQ mass spectrometer is used to implement several new types of tandem mass spectrometry (ms/ms) experiments. New modes of operation of a Paul ion trap mass spectrometer are described including multistage ms/ms experiments. In the BEQQ spectrometer, each experiment utilizes reactions occurring in two separate regions of the mass spectrometer, which are followed by scanning one or more of the fields associated with the magnetic sector, the electric sector, and the quadrupole mass filter. The types of scans that result include a consecutive neutral loss scan which increases the molecular specificity over that available in conventional neutral loss scans. Recognition of the members of particular chemical classes in mixtures is also facilitated by a new selective type of parent scan. Specific compounds can be characterized by use of a new selective daughter scan, which displays a specific subset of the products arising from a particular ion. The use of a Paul ion trap mass spectrometer to generate daughter spectra of selected parent ions is shown. Ions are created within the trap by electron impact, undesired ions are ejected from the trap, and the selected parent ion undergoes collisionally activated dissociation (CAD). The CAD efficiency can be greately increased by applying a small supplementary ac voltage of appropriate frequency. Scan modes which allow daughter spectra to be recorded for the products of ion/molecule reactions and for fragment ions generated in a previous collision (sequential daughter ms/ms/ms) are also illustrated.
Degree
Ph.D.
Advisors
Cooks, Purdue University.
Subject Area
Analytical chemistry
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