Simultaneous capillary electrophoretic determination of Sc(III) and Y(III) based on the complex-formation with a...

Trace amounts of Sc(III) and Y(III) can react with [PW(11)O(39)](7-) to form the ternary Keggin-type complexes: [P(Sc(III)W(11))O(40)](6-) and [P(Y(III)W(11))O(40)](6-) having high molar absorptivities in the UV region. Since the rate of the complex-formation was very rapid and the kinetically stable ternary anions migrated in the capillary with different electrophoretic mobilities, the complex-formation reaction was applied to the simultaneous CE determination of Sc(III) and Y(III) with direct UV detection at 250nm. For both Sc(III) and Y(III), the pre-column method provided linear calibration curves in the range of 2x10(-7) to 1x10(-5)M; the respective detection limits were 1x10(-7)M (the signal-to-noise ratio=3). The proposed method was successfully applied to the determination of Sc(III) and Y(III) in river water.