| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1991: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1990: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Research Abstract |
Selectivity is one of the most important variables to achieve the separation of structually related compounds for identification and quantitation. In Liquid chromatography (LC), selectivity can be controlled by changing the mobile phase composition, the column temperature and/or the type of stationary phases. It is possible to use solvent systems to change selectivity in LC. However, the choice of mobile phases in supercritical fluid chromatography (SFC) is very limited ; the most popular mobile phase is carbon dioxide, into which modifiers are sometimes added. Large changes in selectivity will not be expected, although it is feasible to modify the selectivity by changing the state variables such as temperature and pressure and adding mofifiers. The most effective approach to attain the desiable selectivity in SFC is to alter the type of stationary phases. With packed capillary SFC, various types of stationary phases which offer different selectivity in LC can be utilised. The main pur
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pose of this investigation is to examine the difference in selectivity between LC and SFC using identical stationary phases, especially focusing on their ability to recognize the difference in molecular planarity of polycyclic aromatic hydrocarbons. Then new stationary phases which have different selectivity in LC will be examined in SFC in order to know the basic difference between LC and SFC. As the results, we have found that liquid-crystal bonded phase and cyclodextrin bonded phase have better selectivity in molecular planarity recognition than those in LC, because in SFC mobile phase solvation effect to the solute-stationary phase interaction is smaller than that in LC situation and therefore almost simple molecular-molecular interaction is possible to make in chromatographic environment. The design of new stationary phases based on molecular-molecular interaction can be easily possible to evaluate in SFC, rather than LC conditions. Then the resulted information can be useful to predict the actual performance of such stationary phases in LC. The scheme of designing new stationary phases which can give us better of higher selectivity for particular separations is as follows : design the molecular-molecular interaction, consider the stationary phase structure based on the interaction, synthesize the phase, evaluate the performance by packed column SFC and then apply it in LC. The results of this investigation can clearly indicate this scheme is one of the best way to obtain highly selective stationary phases in LC. Less
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