Renewable-Reagent Electrochemical Sensor for Monitoring Trace Metal Contaminants

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• 作者：Joseph Wang ; Jianmin Lu ; Dengbai Luo ; Jianyan Wang ; Mian Jiang ; Baomin Tian ; and Khris Olsen
• 刊名：Analytical Chemistry
• 出版年：1997
• 出版时间：July 15, 1997
• 年：1997
• 卷：69
• 期：14
• 页码：2640 - 2645
• 全文大小：197K
• 年卷期：v.69,no.14(July 15, 1997)
• ISSN：1520-6882

文摘

This work extends the concept of in situ electrochemicalstripping sensors to environmentally important metalsthat are not readily accumulated by amalgamation. Arenewable-reagent sensor has thus been designed toaccommodate the complex formation and adsorptiveaccumulation steps of adsorptive stripping protocols.Such flow probe relies on the delivery of a ligandsolutionthrough a microdialysis sampling tube and transport ofthe resulting complex to a downstream adsorptive stripping detector. The integrated membrane sampling/adsorptive stripping sensor is characterized, optimized, andtested in connection with the monitoring of trace uraniumand nickel using the propyl gallate and dimethylglyoximechelating agents, respectively. Experimentalvariables,including the reagent delivery rate and ligand concentration, are explored. The microdialysis sampling stepminimizes the interference of surface-active macromolecules and extends the linear dynamic range comparedto conventional adsorptive stripping measurements. Detection limits of 1.5 × 10^-8 M nickel and4.2 × 10^-8 Muranium are obtained following 5- and 20-min adsorptiontimes. A relative standard deviation of 1.7% isobtainedfor prolonged operations of 20 runs. The applicabilitytoassays of river water and groundwater samples is demonstrated. The renewable-reagent adsorptive strippingsensor holds great promise for remote monitoring ofvarious trace metals (via a judicious selection of theligand).