METHOD AND INSTRUMENT FOR ANALYSIS OF ORGANIC ACID

摘要

PURPOSE:To improve the sensitivity of an analysis by adding and mixing a soln. for buffer to and with a mobile phase in which an org. acid is separated and eluted and fixing the liquid characteristic of the soln. mixture to the specific pH sufficiently exceeding the acid ionization indices of respective org. acids, then executing detection. CONSTITUTION:A sample contg. the org. acid is subjected to ion exclusion chromatography using an aq. acidic soln. as the mobile phase and is thereby separated. The soln. for buffer contg. the acid having 6-10 acid ionization index (pKa) is added and mixed to and with the separated eluate from the chromatography to adjust the pH of the liquid mixture at + or -1 acid ionization index of the acid used. The org. acid anion in this soln. mixture is detected in accordance with the electrical conductivity. A change in the concn. of the proton and hydroxide ion arising from the neutralization of the eluate is thereby buffered and the base line noise is decreased, by which the sensitivity is improved.