The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 29, 2012
Filed:
May. 22, 2008
Kazuo Mukaibatake, Kyoto, JP;
Kazuo Mukaibatake, Kyoto, JP;
Shimadzu Corporation, Kyoto, JP;
Abstract
If a scanning rate of a mass scanning is set to be high, the amount of change in an applied voltage between a time of an incidence of a certain ion into a quadrupole mass filter and a time of an emission of the ion therefrom increases. This leads to a change in the condition of a passage of ions, causing the amount of ions to decrease and thereby deteriorating detection sensitivity. In order to avoid this problem, according to the present invention, the values of direct current voltage U and an amplitude V of radio-frequency voltage, both voltages being applied to rod electrodes during a mass scanning, are respectively determined so that a voltage ratio U/V of the voltage U to the amplitude V becomes smaller as the scanning rate becomes higher. Accordingly, in a stability diagram based on the Mathieu equation, the inclination of line L indicating the change in the applied voltage during the mass scanning becomes gradual and the amount of ions passing through the quadrupole mass filter increases particularly when the mass is high.