US 6,147,348 A · Method for performing a scan function on quadrupole ion trap mass spectrometers

Abstract

The subject invention pertains to a scan function which will allow parent and neutral loss scans, with a reduced number of false positives, greater detection efficiency, shortened time periods, and enhanced mass resolution, to be performed on the quadrupole ion trap mass spectrometer. In a specific embodiment, the subject invention involves first trapping ions of interest and obtaining a mass spectrum of the m/z range of interest. The (m/z)'s which are present and meet certain predetermined criteria can then be selected and stored. Ions are again trapped in the ion trap and then all ions with (m/z)'s below that of the first ion of interest are ejected. The first ion of interest is resonantly excited to cause CID and the presence of a particular daughter ion is then determined using a standard mass-selective instability scan over a narrow m/z range with resonant ejection at a predetermined ejection q.sub.z. The ion trap is then cleared of all ions with (m/z)'s below that of the next ion of interest and the process is repeated.

Claims25

Dependent claims

A method for performing a scan function on a quadrupole ion trap, comprising the following steps:

a) trapping sample ions in the ion trap;
b) obtaining a mass spectrum of the sample ions;
c) selecting and storing the mass-to-charge ratios of the ions which are present and/or meet at least one predetermined criterion;
d) trapping additional sample ions in the trap;
e) ejecting all ions with mass-to-charge ratios below the lowest stored mass-to-charge ratio;
f) resonantly exciting ions of the lowest stored mass-to-charge ratio;
g) performing a mass-selective instability scan over a mass-to-charge ratio range of interest;
h) ejecting all ions with mass-to-charge ratios below the next lowest stored mass-to-charge ratio;
i) resonantly exciting ions of the next lowest stored mass-to-charge ratio;
j) performing a mass-selective instability scan over a mass-to-charge ratio range of interest;
and
k) repeating steps h, i, and j until ions of all stored mass-to-charge ratios have been resonantly excited,
wherein the scan provides information about the sample ions.

10 more elements

Dependencies are inferred from the claim text.

Method for performing a scan function on quadrupole ion trap mass spectrometers

Life of this patent

Method for performing a scan function on quadrupole ion trap mass spectrometers

Life of this patent

Abstract

Claims25