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:
Oct. 24, 2000
Filed:
Sep. 29, 1998
Kazuya Nakagawa, Kyoto, JP;
Hiroyuki Tsujiide, Kyoto, JP;
Shimadzu Corporation, Kyoto, JP;
Abstract
An electron capture detector has a detection cell containing an electrode and a radioactive isotope for ionizing a carrier gas and causing electrons to be emitted. Before the detection cell begins to be contaminated, a pulse voltage is applied to the electrode and the frequency of this pulse voltage is controlled by a loop control routine to find an initial pulse frequency value such that a current through the electrode due to the emitted electrons comes to have a specified current value as a carrier gas is introduced into the detection cell. When a sample is analyzed after the detection cell becomes contaminated, the same process is carried out before the sample is injected and a pre-measurement pulse frequency value is obtained. After the sample is injected, the same process is repeated to obtain a measured pulse frequency value. The concentrations of components of the sample are calculated from the measured pulsed frequency value, and the effects of contamination of the detection cell are removed by considering both the initial and pre-measurement pulse frequency values.