BHSU Chemistry Instruments

Scanning Electron Microscope

Our JOEL 5600LV scanning electron microscope actually belongs to the Biology program, where it is used in BIOL 318. In this course, students are taught how to use the machine and are then turned loose to develop their own research project utilizing the electron microscope. Chemistry uses this microscope in collaborative projects such as comparing the crystals of compounds grown under different conditions.

Circular Dichroism

A spectropolarimeter works much like a UV/Vis Spectrophotometer, only with a twist. The light is literally twisted in a helical waveform, and the absorption of left and right circularly polarized (Twisted) light is measured. This effect is called Circular Dichroism, so the machine is often referred to as a CD machine.

Only compounds that are asymmetric, that is, compounds in which the mirror image of the compound cannot be superimposed on itself, will show an absorption in the CD machine. For most everyday types of chemistry, we don't worry about whether or not a compound is asymmetric, but in drugs and in biological compounds, this asymmetry becomes extremely important. For example, a drug made with the incorrect stereoisomer (mirror image) will have no effect on the body at all, while the correct stereoisomer will have a correct effect.

Nuclear Magnetic Resonance (NMR)

NMR stands for Nuclear Magnetic Resonance. An NMR is another machine that is a workhorse instrument because it can be used to identify so many different compounds.

Our NMR instrument consists of a Varian EM390 permanent magnet and an Anasazi EFT-90 console. This gives us an instrument with a 90 MHz proton signal that can do any modern pulse NMR experiments including 2D experiments like the COSY. Our instrument also includes a broadband probe, so we can do a variety of nuclei besides H and C.

We expect the NMR to become one of our central instruments. It will find use in just about every chemistry lab taught at BHSU, as well as being useful in most chemical research projects.

Infrared Spectrometer

An Infrared Spectrometer determines the wavelength and absorbance of a sample in the infrared region of the electromagnetic spectrum. Infrared spectrometers are a major workhorse instrument for the analysis of organic compounds for two reasons. First, the analysis is fast and easy to perform, and second, every organic compound has a unique infrared spectrum that allows any compound to be uniquely identified.

Our instrument is a Matteson Genesis II FTIR. This machine is incorporated into labs in Survey, General Chemistry, Organic, and Analytical classes. Perhaps the most enjoyable lab is in the survey class, where the students fill a plastic garbage bag with auto exhaust, then transfer the exhaust gases into a gas cell and analyze the gas for CO and CO 2 content using the IR.

Atomic Absorption

An Atomic Absorption Spectrometer is used to analyze metals by burning a solution containing the unknown metal in a gas flame, then analyzing the light emitted or absorbed by the flame with a spectrophotometer. This makes this instrument ideal for measuring trace amounts of virtually any metal.

Our instrument is a Perkin Elmer 2290 Atomic Absorption Spectrometer. It is used in classes like Chem 232 - Analytical Chemistry, and Chem 434 - Instrumental Analysis. It is also used in Environmental Chemistry for the analysis of metals found in wells, streams, and other sources around the Black Hills. It is occasionally used by Dr. Tom Cook, a former faculty member, for the analysis of metals found in different galvanizing processes.

UV/Vis Spectrophotometer

The UV/Vis spectrophotometer is an instrument that measures UV and visible light absorbed by a compound. Because the light absorbed by a compound may be used to determine how much of that compound is in a solution, it has many uses in both biology and chemistry.

We have two different kinds of spectrophotometers. The first, a Perkin Elmer Lambda 2 is a computer-controlled, double-beam instrument. This makes it extremely sensitive and accurate, and is a research-grade instrument. This instrument is shared jointly with the Biology department, and is used in many classes both in Biology and Chemistry as well as in many research projects.

The second instrument is an Ocean Optics CHEM-UV Spectrophotometer. The design of this instrument is radically different from the scanning spectrometer. The Ocean Optics machine is a photodiode array machine. In this kind of machine, the entire spectrum can be determined in less than a second, making it a much faster machine for certain kinds of experiments. It is also a much more compact machine, with the bulk of the instrument sitting on a card inside the computer. The only external part is a light source that is the size of the palm of your hand.

Gas Chromatograph (GC)

A gas chromatograph (GC) is used to separate any quantitative compounds that are volatile; that is, materials that can be turned into gases.  Typically GC's are used for characterizing very small amounts (1 or 2 micrograms) of organic compounds.  They have found routine use in drug testing, pesticide research, and many other areas of trace analysis.  We have two Agilent 6890N GC systems, both  split/splitless injectors and FID detectors.  One of these systems has an additional Agilent 5973 Quadrupolar Mass sensitive detector.

The FID detectors (Flame Ionization Detectors) are very sensitive detectors that, essentially, burn the material as it comes off the GC column to turn it into ions and then detects those ions.  With this detector you can observe any material that can be burned, but you cannot directly identify what it is.

The mass sensitive detector is a complete quadrupolar mass spectrometer that determines the mass spectrum of each compound instantaneously as it comes off the GC column.  The mass spectrum is then used to identify each compound. This detector is not quite as sensitive as the FID detector, but the ability to identify each compound as it comes off the column makes it a powerful analytical tool.

High Pressure Liquid Chromatography (HPLC)

HPLC system, or High Pressure Liquid Chromatography system, is used to characterize and purify various liquid samples. Our HPLC system is used primarily in Dr. Zehfus' fisheries research, where samples from fish tissues are injected onto the machine to purify and quantitate the thiamine, thiamine monophosphate, and thiamine pyrophosphate found in these tissues. Next year the HPLC system will also be used to purify peptides synthesized as part of Dr. Zehfus' hydrogen bond project. This instrument is available for use in Chemistry 434, Instrumental Analysis.

Our Waters HPLC system consists of two 501 pumps, a 486 tunable absorbance detector, a 474 scanning fluorescence detector, and a 717 autosampler so the machine can run many samples unattended. A computer using the Waters Millennium software package controls the entire system. Other added components to this system include an Eppendorf TC-45 Temperature control unit and a CH-30 column heater unit. Solvents are degassed using an Alltech NO-OX vacuum degassing system.

Fluorescence

Fluorescence occurs in a compound when a molecule absorbs light of a single energy; that energy is then released as light of a different wavelength when the molecule returns to its ground state. In a Fluorescence Spectrometer, a sample is illuminated with light of one wavelength, and then the machine detects light that is emitted from the sample at a different wavelength. While the number of compounds that are naturally fluorescent is relatively small, the sensitivity of the instrument makes it a powerful method for the analysis of small amounts of certain materials.

The Fluorescence Spectrometer is a Perkin Elmer model 204, and has been used in Chem 434 - Instrumental Analysis, and in research projects. It has been used to quantitate total Thiamine found in samples of fish eggs. Thiamine itself is not fluorescent, but it can be converted to thiochrome, a fluorescent compound. In this form, our Fluorescent Spectrometer could detect as little as 1 nmole of Thiamine per gram of tissue.