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:
Sep. 22, 1981
Filed:
Jun. 18, 1980
Tsuyoshi Yamada, Yokohama, JP;
Showa Denko Kabushiki Kaisha, Tokyo, JP;
Abstract
Provided is a process for analyzing acidic substances by high speed liquid chromatography. An aqueous pH indicator solution is incorporated in an effluent from a column packed with a packing material, and the pH indicator-incorporated effluent is monitored by means of spectrophotometry. As the pH indicator, a sulphon phthalein indicator is used, which is at least slightly soluble in water and has a pH transformation range falling within the pH range of from about 3.0 to about 10.0 and which exhibits, when maintained at a pH lower than the pH transformation range, the minimum transmittance at a wave length of about 420-440 nm and, when maintained at a pH higher than the pH transformation range, the minimum transmittance at a wave length of at least about 558 nm. The packing material is preferably a sulfonated styrene/divinylbenzene copolymer having a total exchange capacity of about 4 to 5 milli-equivalent/gram.