Grantee Research Project Results

2002 Progress Report: A Nanocontact Sensor for Heavy Metal Ion Detection

EPA Grant Number: R829623
Title: A Nanocontact Sensor for Heavy Metal Ion Detection
Investigators: Tao, Nongjian
Institution: Arizona State University
EPA Project Officer: Hahn, Intaek
Project Period: January 1, 2002 through December 31, 2004 (Extended to March 19, 2006)
Project Period Covered by this Report: January 1, 2002 through December 31, 2003
Project Amount: $375,000
RFA: Exploratory Research: Nanotechnology (2001) RFA Text | Recipients Lists
Research Category: Nanotechnology , Safer Chemicals

Objective:

The threat of heavy metal pollution is a serious environmental concern because of the toxicity of such metals for a broad range of living organisms including humans the fact that these pollutants are non-biodegradable. Due to the difficulty in the remediation of sites contaminated with heavy metals, there is an urgent demand for an in situ sensor that is sensitive enough to monitor heavy metal ions before the concentration reaches a dangerous level. This project exploits the phenomena of conductance quantization and quantum tunneling to fabricate nanoelectrodes for in situ detection of metal ion pollution. Our objective is to develop a high-performance and low-cost sensor for the initial on-site screening test of surface and groundwater that will provide early warning and prevention of heavy metal ion pollution.

Progress Summary:

We have developed an electrochemical method to routinely fabricate nanoelectrodes separated by an atomic-scale gap. We have found that electron flow across such a small gap can be approximately described by simple quantum tunneling theory, but also observed a local state effect due to water molecules. Using the nanoelectrodes, we have detected trace amounts of metal ions at the ppt level by forming quantum point contacts. We also have shown that the deposition and stripping potentials can be used to identify the ions, similar to anodic stripping voltammetry.

Future Activities:

We will: (1) extend the method to various metal ions; (2) optimize nanoelectrode structures to improve the sensitivity of the sensor; and (3) develop nanocontacts sensor arrays.

Journal Articles on this Report : 3 Displayed | Download in RIS Format

Publications Views
Other project views:	All 54 publications	13 publications in selected types	All 13 journal articles

Publications
Type	Citation	Project	Document Sources
Journal Article	Boussaad S, Tao NJ, Nagahara L, Zhang R, Tsui R. Detection of protein adsorption with single wall carbon Nanotube device. Chemical Communications 2003; (13): 1052-1503.	R829623 (2002)	not available
Journal Article	Boussaad S, Xu BQ, Nagahara LA, Amlani I, Schmickler W, Tsui R, Tao NJ. Discrete tunneling current fluctuations in metal-water-metal tunnel junctions. Journal of Chemical Physics 2003;118(19):8891-8897.	R829623 (2002) R829623 (2003) R829623 (Final)	Full-text: Journal of Chemical Physics site Exit
Journal Article	Zhang HQ, Boussaad S, Tao NJ. A high-performance differential surface plasmon resonance sensor using quadrant cell photodetector. Review of Scientific Instruments 2003;74(1):150-153.	R829623 (2002) R829623 (Final)	Full-text: Review of Scientific Instruments site Exit

Supplemental Keywords:

nanotechnology, metal ion detection, heavy metal ion sensor, quantum point contact, nanoelectrodes, nanocontacts., RFA, Ecosystem Protection/Environmental Exposure & Risk, Scientific Discipline, Water, Chemical Engineering, Environmental Chemistry, Engineering, Chemistry, & Physics, Chemistry and Materials Science, Monitoring/Modeling, Environmental Engineering, Environmental Monitoring, heavy metals, metal ions, measurement, atomic force microscopy, heavy metal ion detection, monitoring, sensor technology, groundwater, scanning tunneling microscopy, nanotechnology, sensor, metal ion pollution, nanocontact sensor

Progress and Final Reports:

Original Abstract

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.