Cu(II)-3-(5-chlor-2-hydroxy-3-sulfophenylazo)-6-(2,4,6-tribromophenylazo)-4,5-dihydroxynaphthalene-2,7-disulfonic Acid-Co(II) binuclear complexation and its application to the selective determination of cobalt at ng/ml level.
The chromophore, 3-(5-chlor-2-hydroxy-3-sulfophenylazo)-6-(2,4,6-tribromophenylazo)-4,5-dihydroxynaphthalene-2,7-disulfonic acid (CSTDD) was used to complex Cu(II) and Co(II) in aqueous solution at pH 9.43. A binuclear complex of Cu-CSTDD-Co was formed and showed a high selectivity for the determination of Co(II). The spectral correction technique was applied to characterize the complexes. The results showed the formation of complexes of Cu(CSTDD), Co(CSTDD)3 and Cu2(CSTDD)2Co. The quantitative analysis of Co(II) at ng/ml level was carried out by the light-absorption ratio variation approach (LARVA). The results showed that the technique is satisfactory to determine Co(II) at trace level in water samples with a detection limit of 2.3 ng/ml.
Gao
Hong-Wen
HW
Key Laboratory of Yangtze Water Environment of Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai, PR China. hwgao@mail.tongji.edu.cn
Lu
Xiao-Qiao
XQ
Ren
Jiao-Rong
JR
D002138:Calibration; D003035:Cobalt / Q000032:analysis*; D004396:Coloring Agents / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D015394:Molecular Structure; D009282:Naphthalenesulfonates / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry*; D014881:Water Supply / Q000032:analysis
D004396:Coloring Agents; C508035:Cu(II)-3-(5-chlor-2-hydroxy-3-sulfophenylazo)-6-(2,4,6-tribromophenylazo)-4,5-dihydroxynaphthalene-2,7-disulfonic Acid Co(II); D009282:Naphthalenesulfonates; D009942:Organometallic Compounds; D003035:Cobalt