軸方向分散を抑えた陽イオン交換モジュールとイオンクロマトグラフィーへの応用

The suppressor used in ion chromatography is a module placed between the separation column and conductivity detector. The axial dispersion of the sample solution in the suppressor causes a decline of detection sensitivity due to the broadening of the detection peaks. In this paper, we describe a monofilament inserted Nafion tube-type suppressor for anion analysis, which has an axial dispersion-reduced structure. A standard solution containing fluoride, formate, chloride, nitrite, nitrate, and sulfate was measured by means of an ion chromatograph with the fabricated suppressor. The number of theoretical plates and resolution were, respectively, 1.6 to 2.9 times and 1.3 to 1.8 times higher for the fabricated suppressor than a commercially available electrolytic suppressor. These results suggest that the fabricated suppressor has less axial dispersion of the sample than the electrolytic suppressor. In addition, the background level of the conductivity signal with the fabricated suppressor was suppressed to almost the same level as the electrolytic suppressor.