Determination of trace organic dicarboxylic acids and amines by ion-chromatography.
Retention times for various species in separator columns packed with Zipax SAX, Vydac SC, and MicroPak AX-10 anion-exchange resins were compared with those obtained with Dionex separator column for anions. The MicroPak column was found to separate organic dicarboxylic acids, and the logarithm of the retention time of the acids of a homologous series was found to bear a simple relationship to the number of methylene groups between the carboxylic groups. A modified column system, consisting of a post-separator column packed with Vydac CX cation-exchange resin placed between a Dionex separator column for cations and a suppressor column, was able to separate a nine-component mixture of Na(+), K(+), NH(4)(+), methylamine, ethylamine, propylamine, butylamine, dimethylamine and trimethylamine, a separation that is not possible with any other current column system.
Bag
S P
SP
Department of Chemistry, Jadavpur University, Calcutta 700032, India.