Page 26 - Modern Analytical Chemistry

1400-CH01 9/9/99 2:20 PM Page 9

Chapter 1 Introduction 9

Perhaps the most common type of problem encountered in the analytical lab is
a quantitative analysis. Examples of typical quantitative analyses include the ele- quantitative analysis
mental analysis of a newly synthesized compound, measuring the concentration of An analysis in which we determine how
glucose in blood, or determining the difference between the bulk and surface con- much of a constituent species is present
in a sample.
centrations of Cr in steel. Much of the analytical work in clinical, pharmaceutical,
environmental, and industrial labs involves developing new methods for determin-
ing the concentration of targeted species in complex samples. Most of the examples
in this text come from the area of quantitative analysis.
Another important area of analytical chemistry, which receives some attention
in this text, is the development of new methods for characterizing physical and
chemical properties. Determinations of chemical structure, equilibrium constants,
particle size, and surface structure are examples of a characterization analysis. characterization analysis
The purpose of a qualitative, quantitative, and characterization analysis is to An analysis in which we evaluate a
solve a problem associated with a sample. A fundamental analysis, on the other sample’s chemical or physical properties.
hand, is directed toward improving the experimental methods used in the other
areas of analytical chemistry. Extending and improving the theory on which a fundamental analysis
An analysis whose purpose is to improve
method is based, studying a method’s limitations, and designing new and modify-
an analytical method’s capabilities.
ing old methods are examples of fundamental studies in analytical chemistry.

1D KEY TERMS

characterization analysis (p. 9) qualitative analysis (p. 8) quantitative analysis (p. 9)
fundamental analysis (p. 9)

1E SUMMARY

Analytical chemists work to improve the ability of all chemists to chemists to improve existing analytical methods and to develop
make meaningful measurements. Chemists working in medicinal new analytical techniques.
chemistry, clinical chemistry, forensic chemistry, and environ- Typical problems on which analytical chemists work include
mental chemistry, as well as the more traditional areas of chem- qualitative analyses (what is present?), quantitative analyses
istry, need better tools for analyzing materials. The need to work (how much is present?), characterization analyses (what are
with smaller quantities of material, with more complex materi- the material’s chemical and physical properties?), and funda-
als, with processes occurring on shorter time scales, and with mental analyses (how does this method work and how can it be
species present at lower concentrations challenges analytical improved?).

1F PROBLEMS

1. For each of the following problems indicate whether its d. The structure of a newly discovered virus needs to be
solution requires a qualitative, quantitative, characterization, determined.
or fundamental study. More than one type of analysis may be e. A new visual indicator is needed for an acid–base titration.
appropriate for some problems. f. A new law requires a method for evaluating whether
a. A hazardous-waste disposal site is believed to be leaking automobiles are emitting too much carbon monoxide.
contaminants into the local groundwater. 2. Read a recent article from the column “Analytical Approach,”
b. An art museum is concerned that a recent acquisition is a published in Analytical Chemistry, or an article assigned by
forgery. your instructor, and write an essay summarizing the nature of
c. A more reliable method is needed by airport security for the problem and how it was solved. As a guide, refer back to
detecting the presence of explosive materials in luggage. Figure 1.3 for one model of the analytical approach.