Granted Patent
Utility
US 4,808,233 · App. 07/069,473
Method for high pH washing of silica-based chromatographic sorbents
Inventor:
Edward A. Pfannkoch
Patented Case
View Patent ↗
Granted: Feb 28, 1989
Filed: Jul 2, 1987
Inventor
Edward A. Pfannkoch
Assignee (at issue)
W.R. Grace & Co. Conn.
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.