ABSTRACT
Perhaps the most functional denition of analytical chemistry is that it is “the qualitative and quantitative characterization of matter.” The word “characterization” is used in a very broad sense. It may mean the identication of the chemical compounds or elements present in a sample to answer questions such as “Is there any vitamin E in this shampoo as indicated on the label?” or “Is this white tablet an aspirin tablet?” or “Is this piece of metal iron or nickel?” This type of characterization, to tell us what is present, is called qualitative analysis. Qualitative analysis is the identication of one or more chemical species present in a material. Characterization may also mean the determination of how much of a particular compound or element is present in a sample, to answer questions such as “How much acetylsalicylic acid is in this aspirin tablet?” or “How much nickel is in this steel?” This determination of how much of a species is present in a sample is called quantitative analysis. Quantitative analysis is the determination of the exact amount of a chemical species present in a sample. The chemical species may be an element, compound, or ion. The compound may be organic or inorganic. Characterization can refer to the entire sample (bulk analysis), such as the elemental composition of a piece of steel, or to the surface of a sample (surface analysis), such as the identication of the composition and thickness of the oxide layer that forms on the surface of most metals exposed to air and water. The characterization of a material may go beyond chemical analysis to include structural determination of materials, the measurement of physical properties of a material, and the measurement of physical chemistry parameters like reaction kinetics. Examples of such measurements are the degree to which a polymer is crystalline as opposed to amorphous, the temperature at which a material loses its water of hydration, how long it takes for antacid “brand A” to neutralize stomach acid, and how fast a pesticide degrades in sunlight. These diverse applications make analytical chemistry one of the broadest in scope of all scientic disciplines. Analytical chemistry is critical to our understanding of biochemistry; medicinal chemistry; geochemistry; environmental science; atmospheric chemistry; the behavior of materials such as polymers, metal alloys, and ceramics; and many other scientic disciplines.
