Page 99 - Analytical Electrochemistry 2d Ed - Jospeh Wang

84 CONTROLLED-POTENTIAL TECHNIQUES

FIGURE 3-18 Stripping voltammograms for trace iodide in seawater. (Reproduced with
permission from reference 39.)

3-5.5 Applications
The remarkable sensitivity, broad scope, and low cost of stripping analysis have led
to its application in a large number of analytical problems. As illustrated in Figure
3-19, over 30 trace elements can conveniently be measured in various matrices by
the various versions of stripping analysis. The technique has thus proved useful for
the determination of numerous trace metals in environmental, industrial, and clinical
samples, as well as for assays of foodstuffs, beverages, gunshot residues, and
pharmaceutical formulations. Selected applications are listed in Table 3-3. Figure
3-20 displays adsorptive stripping voltammograms for chromium in various envir-
onmental (soil and ground water) samples from contaminated nuclear energy sites.
Stripping analysis has also been an important technique for screening for blood lead
in children (46). Many other unique applications of stripping analysis have been
reported, including studies of metal speciation (oxidation state, metal±ligand inter-
actions) in natural waters, on-line monitoring of industrial processes, in-situ
oceanographic surveys, or remote environmental sensing (40,55,56).

3-6 FLOW ANALYSIS

An electrochemical detector uses the electrochemical properties of target analytes for
their determination in a ¯owing stream. While parameters such as current, potential,