| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 2005: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2004: ¥2,500,000 (Direct Cost: ¥2,500,000)
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| Research Abstract |
High-enrichment/determination system was proposed for environmental trace analyses. Micro-organic ion-associate phase (IAP) was formed in situ from an aqueous sample. A trace analyte converted into hydrophobic species or an originally hydrophobic trace analyte was extracted into the IAP quantitatively during the phase formation. After being discarded the aqueous phase, the IAP was dissolved with a small volume of solvent, and the analyte in the concentrate was determined by an appropriate instrumental method. This technique was applied to the preconcentration/determination of ammonia, nitrite, di(2-ethylhexyl) phthalate, and cadmium at their trace levels in environmental water.
The IAP extraction of several chemical substances from an aqueous phase was studied by determining the distribution constant K_D between ion associate and aqueous phases. K_D was defined as,
K_D=[the concentration of the chemical substances in the IAP]/[the concentration of the chemical substances in the aqueous p
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hase]
Three IAP systems made of benzethonium cation (Ben^+) and phenolsulfonate anion (PS^-), benzyldimethyldodecylammonium cation (C_<12>BzMe_2N^+) and PS^-, and benzyldimethyltetradecylammonium cation (C_<14>BzMe_2N^+) and PS^- were investigated.
The distribution of estrogens (estrone, 17ss-estradiol and ethinylestradiol) between ion associate and aqueous phases made of Ben^+・PS^- was investigated. More hydrophobic estrogens gave larger K_D than less hydrophobic one. For these three estrogens, log K_D had a positive correlationship with n-octanol/water partition coefficient (log K_<ow>). It was cleared that the ion-associate phase of Ben^+・PS^- has higher extractability than octanol.
The differences of log K_D for nonyl phenol, phthalate di-n-pentyl, phthalate di-n-hexyl, phthalate di-n-heptyl and phthalate di-n-octyl in IAP/water were small. The log K_D values for the three IAP systems (Ben^+・PS^-,C_<12>BzMe_2N^+・PS^-, C_<14>BzMe_2N^+・PS^-) were almost the same.
The distribution the chemical substances between ion associate and aqueous phases was successfully expressed in term of solvent extraction equilibrium. It is also cleared that the IAP extraction method is effective for ion associates than neutral species. Less
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