L6.13
GAS CHROMATOGRAPHY Contextual Examples |
Gas Chromatography is important in a number of industrial, research and academic settings. Below are some examples:
Gas Chromatography (GC) is a convenient means to obtain a lot of information about liquid materials. The information generated by modern GC instruments can be used by virtually all sectors of research, product development, and troubleshooting. For example, a technician was given a sample of gasoline that was not performing properly in an automobile. The technician injected the sample of gasoline into a heated port of the chromatograph and measured the resulting peaks. The technician compared a standard sample of fuel with the fuel in question and concluded that the peaks were higher in the poorly performing fuel, indicating higher boiling points. This was a clear explanation as to why the fuel was performing poorly, and the results ultimately traced the problem to the service station at which the fuel was sold.
2. A team approach to using gas chromatography
Technicians are always working in teams to optimize processes, find solutions to problems, or develop new products, and their expertise is critical to the success of the team. For example, at a large refinery, a catalytic cracker, used to break crude oil into useable fractions was not producing enough product for a particular geological area. A team of engineers and technicians was assigned to the problem. The engineers made fine adjustments to the cracker's hardware using gas chromatography. The technicians performed gas chromatography measurements at line and plotted the changes in output of product. Once maximum output of the product was obtained, conditions to the reactor were saved in the computer. The data generated by the technicians confirmed that the changes had increased the production of product. As a result, profits for the reactor increased by six million dollars per year.
3. Application of GC to address an environmental issue
A resident of a housing complex noticed an odor of gasoline in his well water. After contacting an environmental laboratory, a technician was dispatched to sample the water from the well. The technician also noticed that there was a gasoline station across the street from the housing complex, and sampled the gasoline from each of the distribution pumps. Upon taking the samples back to the laboratory, the technician performed a GC/MS analysis using a purge and trap injection system. By comparing the results from the well and the pump, the technician determined that the source of the gasoline odor was most likely the gasoline station. Further analysis of the underground storage tanks reveled that gasoline had been leaking out of the tanks and leeching into the surface water of the neighborhood. As a result of the analyses, the tanks were replaced, and the surrounding soil was replaced.
4. Using EPA methods to identify unknown hazardous wastes
Hazardous waste is an ever-present
modern problem. Some disposers illegally dump hazardous waste to avoid
the expensive disposal costs. At one such field, a housing company was
going to build a dozen homes, and unearthed rusted barrels of unknown contents.
Identifying the contents of these barrels was essential for proper remediation.
Civil engineers, who knew that the Environmental Protection Agency (EPA) has
developed numerous environmental methods to determine specific compounds, took
samples of the earth and sent them to an environmental laboratory for analysis.
A technician used GC/IRD/MS to identify the contents of the barrels. The
Gas Chromatograph provided separation of the components. The inline FTIR
provided aromatic substitutions and ring junction. The Mass Spectrometry
provided molecular weight information. All of the data presented led the
technicians to conclude that the barrels consisted of carbazole, a dye used
in making photographic plates. This finding was presented to a remediation
team which was able to properly dispose of the barrels and clean the site.