Geoscience Reference
In-Depth Information
Table 5.2 Summary of selected analytical methods for molecular environmental geochemistry
Analytical method
Type of energy
Source
Signal
Absorption, emission, and
relaxation spectroscopies, IR
and FTIR
Infrared radiation
Transmitted infrared radiation
Synchrotron X-ray absorption
spectroscopy (XAS), X-ray
absorption near-edge
spectroscopy, extended X-ray
absorption fine structure
Synchrotron X rays
Transmitted or fluorescent X
rays; electron yield
Synchrotron microanalysis, X-ray
diffraction
Synchrotron X rays
Fluorescent X rays
EELS (also called PEELS)
Electrons
Electrons
XPS and Auger spectroscopy
X rays
Electrons
Resonance spectroscopies
NMR
Radio waves (+
magnetic field)
Radio waves
ESR (also called EPR)
Microwaves (+
magnetic field)
Microwaves
Scattering and ablation
X-ray scattering (small angle, SAXS;
wide angle, WAXS)
X rays (synchrotron or
laboratory)
Scattered X rays
SIMS
Charged ion beam
Atomic mass
LA-ICP-MS
Laser
Atomic mass
Microscopies
STM
Tunneling electrons
Electronic perturbations
AFM (also called SFM)
Electronic force
Force perturbation
HR-TEM and STEM
Electrons
Transmitted or secondary
electrons
SEM/EM with EDS or WDS
chemical analysis
Electrons Secondary, or backscattered
electrons
AAS Atomic absorption spectroscopy, AFM atomic force microscopy (also known as SFM), CT
computerized tomography, EDS energy-dispersive spectrometry. EELS electron energy loss
spectroscopy, EM electron microscopy, EPR electron paramagnetic resonance (also known as
ESR), ESR electron spin resonance (also known as EPR), EXAFS extended X-ray absorption fine
structure, FTIR Fourier transform infrared, HR-TEM high-resolution transmission electron
microscopy, ICP-AES inductively coupled plasma atomic emission spectrometry, ICP-MS
inductively coupled plasma mass spectrometry. Reproduced by permission of American Geo-
physical Union. O'Day (
1999
). Copyright 1999 American Geophysical Union
by plotting measured adsorption data against the concentration value of the
adsorbate. Several mechanisms may be involved in the retention of contaminants
on adsorbents, and therefore, several adsorption isotherms with different shapes
may exist. Giles et al. (
1960
) related the shape of the adsorption isotherms to the
adsorption mechanism for a solute-solvent adsorbent system as follows:
• The S-curve isotherm exhibits an initial slope that increases with the concen-
tration of a substance in the solution. This suggests that the relative affinity of
