Analytical Sciences


Abstract − Analytical Sciences, 17(7), 859 (2001).

Successive Determinations of Platinum(II) and Selenium(IV) with 1,4-Dibromo-2,3-diaminonaphthalene in Aqueous Micellar Solutions
Tomoyuki WARASHINA,  Hitoshi HOSHINO, and Takao YOTSUYANAGI
Department of Applied Chemistry, Graduate School of Engineering, Tohoku University, Aobayama, Sendai 980-8579, Japan
Highly sensitive successive determinations for PtII and Se IV ions have been developed based upon reactions with 1,4-dibromo-2,3-diaminonaphthalene (Br2DAN), which forms a near-infrared (NIR) absorbing complex (epsilon=1.2 x105 l mol-1 cm-1 at 800 nm) and an emissive complex (ex. 386 nm, em. 604 nm) for PtII and SeIV ions, respectively, in acidic aqueous micellar solutions. In the presence of a cationic surfactant, cetyltrimethylammonium chloride, the detection limits for PtII and SeIV ions are 1.2 ng ml-1 (3sigma) and 0.98 ng ml-1 (S/N = 3), respectively. Hydrobromic acid plays a key role to enhance the color development of the NIR-absorbing PtII complex. The influences of CuII and ZnII ions at the normal human serum levels are readily tolerated, and interference from FeIII ion at 35 umol l-1 is circumvented by the addition of 50 umol l-1 of polyaminocarboxylates, such as EDTA.