Analytical Sciences

Abstract − Analytical Sciences, 23(6), 655 (2007).

Continuous Flow Analysis Combined with a Light-Absorption Ratio Variation Approach for Determination of Copper at ng/ml Level in Natural Water
Hong-Wen GAO,* Chun-Lei WANG,* Jiang-Yan JIA,* and Ya-Lei ZHANG**
*State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, P. R. China
**Key Laboratory of Yangtze Water Environment of Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, P. R. China
The complexation between Cu(II) and naphthochrome green (NG) is very sensitive at pH 4.09 with the formation of complex ion [Cu(NG)2(H2O)2]2-. It can thus used for the determination of Cu(II) by the light-absorption ratio variation approach (LARVA) with a good selectivity. Both the ordinary detection procedure and continuous flow analysis (CFA) were carried out, where the latter is fit for continuous and rapid analysis of samples. The limit of detection (LOD) of Cu(II) is only 1 ng/ml, which is favorable for direct monitoring of natural water. About 30 samples could be analyzed per hour by CFA. Cu(II) contents in Yangtze River, West Lake, Taihu Lake of China and seawater near Shanghai were determined with satisfactory results. The CFA-LARVA spectrophotometry was the first to be coupled and it will play an important role in the in-situ analysis of natural water quality.