| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2003: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 2002: ¥2,000,000 (Direct Cost: ¥2,000,000)
|
|---|
| Research Abstract |
On the basis of the formation of the polyoxometalates with high molar absorptivities in the UV region, we developed sensitive capillary electrophoretic methods for the simultaneous determination of P(V) and As(V), and of As(V) and As(III). When a mixture of W(VI) and P(V) was heated beforehand, a lacunary Keggin-type [PW_<11>O_<39>]^<7-> complex was formed, being acted as a complexing reagent. The simultaneous determination of Sb(III) and Bi(III) was made possible through the ternary complex-formation. In this case, both oxoanions are incorporated in the peripheral position of the Keggin-type polyoxotungstate structure.
Capillary electrophoresis was successfully utilized for detecting isopolyoxotungstates in aqueous and aqueous-CH_3CN media of 5.0 mM W(VI), and the formation and transformation processes of isopolyoxotungstates including [W_<10>O_<32>]^<4->, [H_2W_<12>O_<40>]^<6->, [W_7O_<24>]^<6-> and [W_6O_19>]^<2-> wwere established as functions of the buffer pH, the reaction time, the reaction temperature and the CH_3CN concentration.
We found that W(VI) reacted directly with V(V) in acidified aqueous-CH_3CN media to form the Keggin-type [VW_<12>O_<40>]^<3-> and its vavadium-substituted derivative, [V(VW_<11>)O_<40>]^<4->. On the basis of the findings, we developed high-sensitive adsorptive voltammetric methods for the determination of various oxoanions. Both tungstovanadates were characterized voltammetrically and the role of the central and peripheral V atoms in the voltaminetric properties were elucidated.
|
