2.5.2. Trace contaminant detection
In trace organic or inorganic contaminant detection, nanomaterials
can be used in both concentration and detection.
CNTs have great potential for environmental analysis of trace
metal or organic pollutants as they offer high adsorption capacity
and recovery rate as well as fast kinetics as discussed in
Section 2.1.1. The pre-concentration factors for metal ions
were found to be between 20 and 300 with fast adsorption
kinetics (Duran et al., 2009). CNTs have also been extensively
studied for preconcentrating a variety of organic compounds,
many of which were done in real water samples (Cai et al.,
2003). Adsorption of charged species to CNTs results in
changes of conductance, providing the basis for the correlation
between analyte concentration and current fluctuation
(Mauter and Elimelech, 2008).