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.
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 Eclipse 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.
Fourier Transform Infrared Spectrophotometers
The Department has three Fourier transform
infrared spectrometers; a Nicolet iS10, a Perkin Elmer Spectrum 2 and a Perkin
Elmer Spectrum 1000. Accessories for attenuated total reflectance (ATR)
and diffuse reflectance (DRIFT) are available for use on the instruments. 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.