| Budget Amount *help |
¥12,600,000 (Direct Cost: ¥12,600,000)
Fiscal Year 2004: ¥5,400,000 (Direct Cost: ¥5,400,000)
Fiscal Year 2003: ¥7,200,000 (Direct Cost: ¥7,200,000)
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| Research Abstract |
The proposed open tubular capillary liquid chromatography(OTCLC) system utilizes the recent discoveries of "microheterogeneity" in some organic-water mixed solvents and salting-out phase separation phenomena observed in these mixed solvents. For example, acetonitrile is miscible with water at any ratio ; heterogeneities, however, have been observed at a molecular level in its water mixtures. When an acetonitrile-water mixture of suitable salt concentration is pumped into such a capillary micro-phase separation is likely happening in the vicinity of the capillary wall, in a water-enriched aqueous phase attached to the capillary inner wall. In other words, a liquid membrane that has considerably different properties from the mobile phase is dynamically formed on the inner wall of the capillary.
When a mixture of analytes is injected into the capillary, participation of the analytes occurs between the mobile phase and the liquid membrane, providing the separation power of the proposed chromatograpy system.
Chromatographs clearly demonstrated the ability of separating neutral compounds from charged compounds by the OTCLC system. Moreover, it was also possible to separate compounds of similar molecular structure but different charges. The elution orders can readily be explained by the retention mechanism. p-Nitroaniline is effectively extracted to the upper (acetonitrile-enriched) phase while 2,7-NDS remains in the lower (water-enriched) phase, confirming the elution order observed. The high concentration of acetonitrile content in the mobile phase slightly increased the elution time of 1-naphthol but significantly increased the elution time of 2,6-naphtalene disulfonic acid. More interestingly, at the absence of NaCl, no separation in both cases (AN/aq 9/1 and AN/aq 8/2) were observed, demonstrating the necessity of additional electrolyte for the micro-phase separation in the capillary tubing.
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