High-speed ion-exclusion chromatography of dissolved carbon dioxide on a small weakly acidic cation-exchange resin column with ion-exchange enhancement columns of conductivity detection

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• 作者：Masanobu Mori ; Mikaru Ikedo ; Wenzhi Hu ; Murad I.H. Helaleh ; Qun Xu ; Hideyuki Itabashi ; Kazuhiko Tanaka
• 关键词：Water analysis ; Ion-exclusion chromatography ; Dissolved carbon dioxide ; Conductivity ; Ion-exchange ; Calibration linearity
• 刊名：Journal of Chromatography A
• 出版年：2005
• 出版时间：28 October 2005
• 年：2005
• 卷：1092
• 期：2
• 页码：250-253
• 全文大小：147 K

文摘

The high-speed ion-exclusion chromatographic determination of dissolved carbon dioxide, i.e., carbonic acid, hydrogencarbonate or carbonate, with conductivity detection was obtained using a small column packed with a weakly acidic cation-exchange resin in the H⁺-form (40 mm long × 4.6 mm i.d., 3 μm-particle and 0.1 meq./ml-capacity). Two different ion-exchange resin columns, which were a strongly acidic cation-exchange resin in the K⁺-form and a strongly basic anion-exchange resin in the OH⁻ -form, were connected after the separation column. The sequence of columns could convert dissolved carbon dioxide to KOH having high conductivity response. The enhancement effect for dissolved carbon dioxide could retain even on the vast chromatographic runs, by using the enhancement columns with high ion-exchange capacity above 1.0 meq./ml. The retention time was in 60 s at flow-rate of 1.2 ml/min. The calibration graph of dissolved carbon dioxide estimated as H₂CO₃⁻ was linear in the range of 0.005–10 mM. The detection limit at signal to noise of 3 was 0.15 μM as H₂CO₃⁻. This method was applicable to several rainwater and tap water samples.