Mass Spectrometers (MS)
Varian Gas Chromatograph-Mass Spectrometer
The GC-MS is a combination instrument that permits sequential separation of a mixture of chemicals found after a chemical reaction is carried out, or from a mixture obtained as the result of chemical extraction of a plant, forensic or environmental sample. Volatile components of the sample are put through a gas chromatograph, followed by identification of the compounds contained in the sample by the characteristic mass spectrum exhibited. Located in one of our instrument rooms shown here, is the Varian GC-MS (next to Dr. Schaefer), together with a Varian stand-alone GC.
The GC-MS, and the GC, are workhorse instruments designed to simplify the identification of unknown chemicals and is vital for any work involving the characterization of an unknown material in traditional organic chemistry, environmental chemistry, forensic chemistry, or drug analysis. At USciences, this instrument is often used by students in the Pharmacognosy graduate program for the analysis of pharmacologically active compounds extracted from plants. If you would like more information about the capabilities of this instrument, please contact Dr. Fred Schaefer.
Mass Spectroscopy - What does it do?
Mass spectrometry is another of the very powerful tools available for the determination of the structure of a molecule through the measurement of the mass of the intact molecule and the mass of the fragments produced under certain specific experimental conditions. The fragmentation pattern obtained is diagnostic of what types of atom groupings are present in the molecule. For example, if a fragment with a mass of 17 amu is obtained, that would suggest that the molecule contains the hydroxyl group (-OH) attached somewhere on the carbon framework. Similarly, if a fragment with a mass of 31 amu is obtained, that would suggest that the methoxy group (CH3O-) is present. By analyzing the masses of all the fragments obtained, it is usually possible to reconstruct the overall structure of the molecule.