Atomic Spectroscopy for Metal Analysis - Fundamentals of Environmental Sampling and Analysis - page 236

For mercury and those elements that form hydrides, the cold vapor mercury or
hydride generation techniques offer exceptional (low) detection limits.
The analytical range is the concentration range over which quantitative results
can be obtained without having to recalibrate the system. An ideal working range
minimizes analytical effort (e.g., dilution, concentration) and time by allowing
many samples with analyte concentrations within that range to be analyzed together.
Figure 9.10 shows the typical analytical working ranges with a single set of
instrumental conditions. The wideness of the working range increases in the order
of: GFAA < FLAA < ICP-OES < ICP-MS. For instance, the ICP-MS has 8 orders

of magnitude of signal intensity.

Figure 9.10 Typical analytical working ranges for the major atomic spectroscopy techniques
(Courtesy of Perkin-Elmer, Inc.)

9.3.2 Comparison of Interferences and Other
Considerations

Interference

Interference is one of the major issues to deal with in atomic spectroscopy. There
are three types of interferences: spectral, chemical, and physical. Table 9.2 shows
the types of interference for various atomic spectroscopic analyses and the methods
of compensation. Basic terminology is provided below. For specific details, the
reader should consult the excellent textbook by Skoog et al. (1997).
Spectral interference: Spectral interference occurs in both atomic emission and
atomic absorption spectroscopy. In atomic emission, the spectral interference occurs
when either another emission line or a molecular emission band is close to the
emitted line of the test element and is not resolved from it by the monochromator.
Such molecular emission could come from the oxides of other elements in the
sample (refer to Fig. 9.1). In atomic absorption spectroscopy, solid particles,
unvaporized solvent droplets, or molecular species in the flame can cause a positive
spectral interference.
The interelement effects and background absorption are more pronounced in the
GFAA than in the FAA system. Such spectral interference can be corrected by a