OPPapers.com Essay Index >> Science >> Gc/Ms
We have many free term papers and essays on Gc/Ms. We also have a wide variety of research papers and book reports available to you for free. You can browse our collection of term papers or use our search engine.
... They have been able to detect THG using the GCMS, gas chromatograph mass spectrometer,
and caught a handful of athletes that have tested positive. ...
... metabolizes them. So the current and the most accurate way of testing is
through gas chromatography-mass spectrometry (GCMS). The ...
... as confusing labeling terminology and instructions” (Bunn 2). Conversely, previous
courts have provided compelling support for the EMIT and GCMS urine tests ...
Submitted by mmgonsalves on October 31, 2006
Category: Science
Words: 1303 | Pages: 6
Views: 535
Popularity Rank: 15,078
Average Member Grade: N/A (Add a Comment / Grade this Paper)
Purpose:
The Purpose of this experiment is to determine the quantity of caffeine in a sample using an instrument called Gas Chromatography-Mass Spectroscopy (GC-MS). The caffeine samples that are evaluated are coffee, espresso and a deuterated caffeine sample (d3), given by the T.A., of unknown concentration was used as an internal standard.
Theory:
The GC-MS instrument combines two different techniques to form one single method of analyzing mixtures. Gas chromatography performs the separation of components in a mixture, and the mass spectroscopy distinguishes the individual constituent.
A mixture of different specimens can be separated by GC. A sample is injected into the instrument through an injection port. The injection port is maintained at certain mixture, which is called its’ mobile phase, to the stationary phase of the instrument. The stationary phase is the GC column, where each compound in the mixture interacts at different rates, and therefore separated. The different molar characteristic determines how compounds will relate with the column. The substances that do not stick to the column elutes faster from the column than the ones that do. The oven temperature in the GC is ramped to make further separations. The ones with a higher point boiling point elutes at a quicker rate.
After separation is achieved, the components enter a detector where an electronic signal can be created whenever a component is detected. The signal size is dependent on tcomponent’s concentration. A retention time, which is the time from the injection is made to when elution occurs, is calculated by the instrument computer. The retention time is nearly the same for a compound, as long as GC conditions are the unchanged. Assumptions can be made about a compound’s identity if its’ retention time is known.
The eluted samples from the GC enter the Mass Spectrometer’s electron ionization...
You must Login to view the entire paper.
If you are not a member yet, Sign Up for free!