Ionic chromatography-conductivity detection

K Tanaka, JS Fritz. Ion-exclusion chromatography of non-ionic substances with conductivity detection. J Chromatogr 409 271-279, 1987. 

Because the species detected by conductivity detection are ionic, ion-exchange and ion-pair chromatography are the separation modes most often used. Both methods require mobile phases containing strong electrolytes however, the detector must detect the ionic solutes without being over-... 

Mobile phases useful for suppressed conductivity detection of anions include sodium hydroxide, potassium hydroxide, and the sodium and potassium salts of weak acids such as boric acid. In nonsuppressed conductivity detection, the ionic components of the mobile phase are chosen so that their conductivities are as different from the conductivity of the analyte as possible. Large ions with poor mobility are often chosen, and borate-gluconate is popular. For cations, dilute solutions of a strong acid are often used for nonsuppressed conductivity detection. For more information on the application of electrochemical detection to inorganic analysis, see Ion Chromatography Principles and Applications by Haddad and Jackson,17 which provides a comprehensive listing of the sample types, analytes, sample pretreatments, columns, and mobile phases that have been used with electrochemical detection. 

Ion chromatography is used for the separation of ionic solutes such as inorganic anions and cations, low molecular-mass water-soluble organic acids and bases as well as ionic chelates and organometallic compoimds. The separation can be based on ion-exchange, ion-pair and/or ion-exclusion effects. Special detection techniques like ion-suppressed conductivity detection or indirect UV detection have to be used because most analytes are transparent to conventional UV detection... 

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