Solvent extraction of copper acetylacetonate in studies of copper(II) speciation in seawater
Solvent extraction of copper acetylacetonate in studies of copper(II) speciation in seawater
复制标题
乙酰丙酮铜的溶剂萃取用于海水中铜 (II) 形态的研究
DOI：
10.1016/0304-4203(87)90053-3
复制
发表时间：
1987
期刊：
影响因子：
3
通讯作者：
R. Zika
中科院分区：
文献类型：
--
作者：
J. Moffett;R. Zika
A liquid-liquid partition, ligand exchange procedure involving the formation of copper(II) complexes with acetylacetone is presented for the determination of stability constants and concentrations of copper chelators in seawater. Acetylacetone competes with natural ligands for copper, and the equilibrium concentration of the copper acetylacetonate complex is used in speciation calculations. The concentration of the complex is calculated by partitioning a fraction of it into an organic phase and determining the total Cu concentration in that phase by back extracting with acid, and analyzing by flameless atomic absorption spectroscopy. The concentration of Cu acetylacetonate in seawater in equilibrium with the organic phase is calculated from the partition coefficient. The simple, thermodynamically well characterized procedure offers several advantages over previous techniques. Studies using organic free seawater and model ligands show good agreement between experimental and calculated conditional stability constants. Studies from seawater in Biscayne Bay, Florida, indicate two ligand types are present; type 1, K1= 1.2 × 1012,CL1= 5.1 × 10−9M; type 2, K2= 2.8 × 1010, CL2= 1.1 × 10−7M. Speciation is dominated by ligand type 1. Depth profiles of [Cu(II)]free/[Cu(II)]totalmeasured with the procedure at ambient copper concentrations show an increase from < 5 × 10−5at 50–60 m to > 1 × 10−3at the surface at two stations off the Florida coast.
