Page 4 - Academic Press Encyclopedia of Physical Science and Technology 3rd Analytical Chemistry

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Encyclopedia of Physical Science and Technology En001f25 May 26, 2001 14:30

Analytical Chemistry

Ulrich J. Krull
Michael Thompson
University of Toronto

I. Classical Methods
II. Instrumental Methods
III. Computers in Analytical Chemistry
IV. Future Perspectives

GLOSSARY Quantitative analysis Process of determining the rela-
tive amounts of one or more component(s) in a sample
Accuracy Nearness of a measurement to its accepted of matter.
value. Resolution The ratio given by the average magnitude of
Analyte Species present in a sample of matter about an analytical variable divided by the smallest difference
which chemical information is sought. of values of the analytical variable, where each value
Calibration Process of determining the precise quanti- provides analytical signals that are considered distinct
tative relationship between a known concentration of by statistical techniques.
a chemical species and a physical property of that Selective Method in analytical chemistry that yields a re-
species. sponse for a group of chemical species.
Interferences Elements or chemical compounds that Sensitivity Ratio of the change in the response of an in-
have similar properties to the analyte that prevent its strument with a corresponding change in the concen-
direct measurement. tration of a chemical species.
Limit of detection Concentration of a chemical species Specific Method in analytical chemistry that yields a re-
that produces an analytical signal equal to twice the sponse for a single chemical entity only.
standard deviation of the background signal. Standard Chemical species with well-established physi-
Matrix Matter present in a sample in which the species cal properties that is employed to calibrate an analytical
being determined is dispersed. procedure.
Noise Random fluctuations of analytical signal with time.
Precision Statistical measure of the distribution of a se-
ries of analytical determinations about the average ANALYTICAL CHEMISTRY is concerned with pro-
value of the same analytical determinations. viding qualitative and quantitative information about the
Qualitative analysis Process of identifying one or more chemical and structural composition of a sample of mat-
component(s) in a sample of matter. ter. A huge variety of samples, from high concentrations of

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