|Budget Amount *help
¥1,500,000 (Direct Cost : ¥1,500,000)
Fiscal Year 1992 : ¥300,000 (Direct Cost : ¥300,000)
Fiscal Year 1991 : ¥300,000 (Direct Cost : ¥300,000)
Fiscal Year 1990 : ¥900,000 (Direct Cost : ¥900,000)
A noble method to concentrate hydrophobic solutes from water to Teflon (polytetrafluoroethylene) film surface has been studied. A test-tube containing 10 ml of an organic solvent (chloroform or benzene) and a cylindrical separatory funnel containing 500 ml of aqueous sample solution were connected together with a Viton diaphragm airpump. A PTEE-seal-tape (20 cm lpng, 1.3 cmwide, 0.1 mm thick) was placed on the water surface. The organic solvent vapor generated by bubbling air was dispersed through the sample solution via a sintered glass ball and circulated in the closed system. Then, the film was picked up and the solute held on it was eluted with a suitable organic solvent. As solutes, Fe (III)-8-hydroxyquinoline, dithizone complexes with Hg(II), Pb(II), Ag(I), and Cd(II), and PAN complexes with Co (II), Ni(II), Cd(II), and Zn(II) were used. Recoveries of these metal complexes by PTFE film were found to be more than 80%. The mechanism of the present concentration method is found to b
e similar to that of conventional solvent extraction: chloroform molecules, being supplied continuously to the aqueous solution, cover the surface of the PTFE film to form a thin organic solvent layer which takes part in the partition of hydrophobic solutes. The thickness of the chloroform layer, which assumed to be formed on the surface of PTFE film upon circulating chloroform vapor in aqueous solution, was roughly estimated to be 10mum based on the recoveries of five free ligands of known chloroform/water partition constants.
A technique was also proposed to prepare cyclodextrin(CyD) precipitates with volatile hydrocarbons. On introducing vapor of liquid or solid hydrocarbon into alpha-, beta-, or gamma-CyD in aqueous solution and circulating in a closed system, CyD can be easily precipitated. The CyD precipitates isolated from aqueous solution were analyzed to determine the hydrocarbon/CyD mole ratio. The technique has been applied to such hydrocarbons as n-alkanes(C_5 to C_<10>), cyclohexane, halobenzenes(fluoro-, chloro-, bromo-, and iodo-benzene), p-difluorobenzene, benzene, naphthalene, biphenyl, and diphenylmethane.