Electrochemical Sensing System for Determination of Heavy Metals in Seawater

A novel electrochemical flow sensing system for determination of heavy metals in seawater is described in this paper. Processes including on-line filtration, UV digestion, electrochemical enrichment, and ion-selective electrode potentiometric detection are involved in the system for sensitive, selective and rapid detection. For measurements of cadmium, lead and copper ions in seawater matrix, the linear response ranges are 1.0 × 10−9−1.0 × 10−7 M, 3.0 × 10−9−1.0 × 10−7 M and 1.0 × 10−9−1.0 × 10−7 M, respectively with the corresponding detection limits of 2.8 × 10−10, 6.6 × 10−10 and 5.1 × 10−10 M. For six successive measurements, the system showed relative standard deviations of less than 5%. The whole analysis process could be completed within 25 min. The system was applied to determination of heavy metals in seawater and the results agreed with those obtained by stripping voltammetry. With advantages of simplicity, accuracy and low cost, the sensing system offers promising potentials for on-site analysis of heavy metals in seawater.