Environmental Engineering Reference
In-Depth Information
(a)
0.6
0.5
0.4
0.3
0.2
0.1
Instrumentation
Sample preparation
0
Sampling
CNTs
FULs
(b)
Analytical chemistry
CNTs Applications
Period covered 2009-2011
Stationary phases
GC, LC, CEC
Separation
science
Part of membranes
Pseudostationary
phases
CE
Sorbents
SPE
SPME
DI substrates
MALDI
SALDI
(c)
Chemical
sensor
MP
I
Fullerenes
as analytical
tools
On-line
preconcentration
D
GC
LC
figure 14.2 (a) Recent applications of CNTs and FUls in environmental analysis (based on published data, from http://www.sciencedirect.
com ). (b) The use of CNTs in analytical chemistry in the period 2009-2011. Reproduced with permission from Ref. [3]. © science direct
Elsevier. (c) The use of FUls in analytical chemistry. Reproduced with permission from Ref. [4]. © science direct Elsevier.
fabricated in small capillary tubings and also by micromachining silicon and other substrates. The interesting liquid-phase
preconcentrating applications are micro-scale solid-phase extraction (μ-sPE) and solid-phase microextraction (sPME) [4-6].
Functionalization of CNTs offers a unique opportunity for altering the physical and chemical characteristics of CNTs. The
presence of a covalently attached functional group can alter the retention/affinity of the CNT surface and important properties
such as polarity, hydrophilicity, and other specific interactions. The functional groups may also alter diffusional resistance and
reduce the accessibility and affinity of CNT surfaces for certain analytes. Functionalization also enhances interaction with poly-
mers and other materials, thus facilitating the formation of composites that can be used as preconcentrating substrates. These
include polymers and sol-gel-type immobilization [6]. Covalent and noncovalent functionalization are shown in Figure 14.4.
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