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Absorption Spectrophotometers
The Department has a variety of different absorption spectrophotometers.
Some are very routine instruments capable of taking absorbance readings
at only a single wavelength, while others, such as our Hewlett-Packard
diode array instrument, are capable of taking an entire spectrum with
one pulse of light. The Cary instrument below is an example of a scanning
instrument, i.e., an instrument which obtains spectra by measuring
the light absorbed by the sample as different wavelengths of light
are passed through the sample.
 Cary UV-Vis-NIR Spectrophotometer
The Cary UV-Vis-NIR spectrophotometer is a rapid-scan instrument that
uses a pulsed xenon lamp, and is capable of measuring absorption spectra
in the ultraviolet, visible and near infrared regions of the spectrum from ~200 nm
out to 900 nm. It's also equipped with a solid-state temperature controller which allows
measurement of absorption spectra as a function of temperature. This instrument is used
in several of our laboratory courses, as well as in research. If you would like
more information about the applications of this instrument in teaching and research,
please contact Dr. Fred Schaefer.
Fluorescence Spectrophotometers
The Department has available two very capable fluorescence spectrophotometers, one made
by PTI (Photon Technology Instruments) and one by Varian/Cary. Both instruments are capable
of measuring excitation and emission spectra, as well as the lifetime of samples as a function of
temperature. The PTI instrument is more sensitive, and is also capable of measuring
fluorescence anisotropy. The PTI instrument is based on modular construction, facilitating the
attachment of accessories, such as laser light sources for excitation of the fluorescence,
which allows lifetimes to be measured into the picosecond regime. These instruments are used
primarily in our upper-division physical chemistry and analytical chemistry laboratory courses
and for research. The Cary fluorescence instrument is discussed in more detail below.
Cary Fluorescence Spectrophotometer
The Cary fluorescence spectrophotometer is capable of measuring excitation
and emission spectra in the ultraviolet, visible and near infrared regions of the
spectrum, roughly from ~200 nm to ~900 nm. It is also capable of measuring millisecond and
longer lifetimes, typically referred to as phosphorescence (note: the PTI instrument is capable of
measuring faster lifetimes, in the microsecond region, or more with the appropriate laser
excitation source). The Cary instrument is also equipped with a solid state temperature
control device that allows spectra to be measured as a function of temperature. If you would
like more information about the applications of these fluorescence instruments in teaching
and research, please contact Dr. Fred Schaefer.
Perkin-Elmer Fourier Transform Infrared Spectrophotometer
Infrared spectroscopy, which measures infrared (IR) energies absorbed
due to molecular vibrations, is typically used to identify the functional
groups (aldehydes, ketones, etc.) and kinds of bonds (C-C, C=C, C-O,
C-N, etc.) present in an organic molecule. The IR spectrum is often
referred to as the "fingerprint" of a molecule, and provides a quick
means of identification. The instrument shown is a computer controlled
Fourier Transform IR (FTIR) which is used by students primarily in the sophomore
organic laboratory to demonstrate that they have synthesized the molecule
assigned. If you would like more information about this technique
and its applications in teaching and research, please contact
Dr. Fred Schaefer.
 Thermo Atomic Absorption Spectrophotometer
Atomic absorption spectroscopy is probably the most common instrument
used to analyze samples for their metal content in the part per
million (ppm) range. The ability to detect lead, mercury and chromium
at very low concentrations makes it the logical choice for use in
environmental studies. The instrument is used primarily in the instrumental
analysis laboratory, and in research. If you would like more information about the
applications of this instrument in teaching and research, please
contact Dr. Fred Schaefer.
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