Granted Patent
Utility
US 5,117,109 · App. 07/578,267
Exchange method of mobile phase in high-performance liquid chromatography mass spectrometry and its apparatus
Inventors:
Naoki Asakawa, Hiroshi Ohe, Yutaka Yoshida, Tadashi Sato, Yukuo Nezu, Yoshiya Oda
Patented Case
View Patent ↗
Granted: May 26, 1992
Filed: Sep 6, 1990
Inventors
Naoki Asakawa
Hiroshi Ohe
Yutaka Yoshida
Tadashi Sato
Yukuo Nezu
Yoshiya Oda
Assignee (at issue)
Eisai Inc.
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.