Advantages:
1. Multiple readings at once
2. The scan time is very short (approx 1 s) (4)
3. Scan Range is very wide (4)
4. The sound to noise ratio is much higher than previous IR (4)
Disavantages:
1. Must use Fourier Transfrom equation in order to interpret data. (5)
2. Because there are mutiple readings at once, the noise in one reading will spread to all readings (5)
3. Single beam, therefore if there is atmospheric changes, it would affect the data greatly (5)
Conclusion:
- The concentration of the xylene isomers were found to be p- Xylene 0.12% xylene, m-Xylene 0.26% xylene, o-Xylene 0.14% xylene.
- This experiment is important because, as mentioned earlier, the toxic air of gasoline is being studied by looking at what makes up the gasoline.
- Also, it can help tell the grade of the gasoline used in cars is by how pure the xylene isomers are.
- There are also other uses of identifying isomers, such as determining the make-up of an unknown material and also isolating a certain xylene to test its effects on other chemicals.
Discussion:
Data Interpretation:
- The calibration curves were created based off of the second table. The data was then used to create a linear line that was used to find the unknown concentrations of the xylene isomers in the unknown and in the gasoline
- The concentrations were found by using the equations from the calibration curves and plugging in the absorbances to the equation to get the concentration.
Errors:
- Sample Solution 2 and 3 were mislabeled creating a non-linear fit
- Multiple uses of the eppendorf pipet creates multiples of errors
- Sample Cell misloading
Chemicals and Materials
Reagents:
- 100% pure m-, o-, p- xylenes
- Cyclohexane
- Small sample of gasoline
Materials:
- (3)- 5 mL Volumetric Flasks
- (7)- 10 mL Volumetric Flasks
- Precision IR Cell
- 100-1000 microLiter eppendorf pipet
FT-IR
Fourier Transform Infrared spectroscopy is used to analyze the transmittance and absorbance of a sample. This is done by measuring multiple infrared frequencies together (3)
(3)"Introduction to Fourier Transform Infrared Spectrometry." Thermonicolet. Cal Tech, 2001. Web. 14 Oct. 2015. <http://mmrc.caltech.edu/FTIR/FTIRintro.pdf>.
(4):Birkner, Nancy, and Qian Wang. "How an FTIR Spectrometer Operates."Chemwiki. UC Davis, 2 Oct. 2013. Web. 15 Oct. 2015.
(5):Eaton, Peter. "FTIR Tutorial." 13 Aug. 2001. Lecture.
Introduction
- This experiment is used to determine the concentration of different xylene isomers that a gasoline contains
- Gasoline contains xylenes that are distilled from a stream that is from the refinement of high-octane motor gasoline (1)
- This is important because the combustion of gasoline releases toxins into the air and being able to identify the xylene isomers can help determine what toxins are inside of the gasoline (2)
(1): "Xylenes." Shell Global. Accessed November 16, 2015. http://www.shell.com/global/products-services/solutions-for-businesses/chemicals/products/aromatics/xylenes.html.
(2):Ganesan, Kumar. "Air Toxic Solutions." Air Toxics: Problems and Solutions. Amsterdam: Gordon and Breach, 1996. Print.
Identifying Xylene Isomers
Presented by: Grace Montgomery
Lab Partner: Rachel Wampler
Date Completed: October 6, 2015
Lab #2