The overlay shows the spectra obtained for each of the individual solvents. Overall, the three spectra are about the same, but unique peaks for each solvent can be seen. The wavenumber regions containing the unique peaks are the ones that give good pca plots, setting solvents in their own, well defined clusters. Five wavenumbers for different wavenumber regions from each of the runs were recorded (five sets of values for each solvent and fifteen sets total; Appendix a, table -0.1.4.9.4.9. Absorption wavenumber (cm-1) overlay of Absorption at a good range of wavenumbers for Organic Solvents Acetone methyl Ethyl Ketone Ethyl Acetate figure 1 This overlay plot shows the different absorptions of different organic solvents at various wavenumbers. There are some peaks that are unique to a solvent, such as that at 1100 being unique to ethyl acetate, and some that all of the solvents have in common, such as 1700. Pcascores wavenumber Region Comparison of pca scores for Organic Solvents Acetone methyl Ethyl Ketone Ethyl Acetate figure 2 This figure shows the different pca scores obtained for the assigned wavenumbers obtained from the ftir data. The wavenumber values chosen for the first wavenumber region were unique to each solvent. With the last three wavenumber regions, the solvents cannot even be distinguished from one another.
Pca scores are plotted against each other to define clusters of unique components. Pca plot has no defined book clusters, the pca scores at those values do not truly contribute any distinguishing features of the individual samples. Pca plots can have clustering in either specific points or elongated areas, so long as each component has a defined cluster separate from the other components. Experimental Methods: For this experiment, there were no deviations from the experimental procedure. The only manipulation of data was plugging results from ftir into the matlab software; this was explained in the appendices for the experiment. Schnell 3, data and Results: The first part of this experiment was performed to practice working with the fourier. Transform infrared spectroscopy (ftir) and the Principal Component Analysis (pca matlab. The practice was done with three different organic solvents. The ftir spectra collected from acetone, methyl ethyl ketone, and ethyl acetate are shown in Figure.
Partner: no partner, march 29, 2016, april 7, 2016. Analytical Chemistry, cHEM:3430:0A01, prof. Schnell 2, introduction: In this experiment, we first used fourier Transform infrared spectroscopy (ftir) to obtain absorbance spectra of different organic solvents and oils. Ftir works by measuring characteristic vibrational frequencies (or wavenumbers) through absorption of ir-radiation from about 4000 to 400 cm-1. Although many peaks may be observed, only the most intense few say something about the component you are testing. Principal Component Analysis (in this case matlab) was then used to reduce redundant information from the obtained data sets. The pca helps to find combinations of strongly correlated factors in the spectra from the sets of data. Pca scores were used to identify the unknown oil by choosing which oils pca scores resembled the unknowns the best.
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Save your spectrum as a jpeg file on your usb drive. (If you must print your spectrum, click on the Print icon system to print a copy of your spectrum.). Remove your liquid sample with KimWipes or use the vacuum to remove your solid sample from the sample area. Then, use damp ethanol KimWipes to thoroughly clean the sample area and pressure arm. Click the delete icon to clear the screen for the next user, or if nobody is waiting, please Exit the program. The following is an example data table which you should use to display the data given in your infrared spectra. Experimental Frequencies (cm-1) Literature Frequencies (cm-1) * Possible peak assignments n-h stretch: 2o amine oh stretch: alcohol, phenol co stretch: carboxylic acid, ketone, aldehyde (Literature ir frequency absorptions were taken from Table 1 below) Table 1: Principal ir absorptions for Certain Functional Groups above 1400.
Type of Vibration (causing ir absorption) Alkanes: (Note: The absorptions can be seen a several distinct peaks in this region.) c-h stretch c-h bend Alkenes: c-h stretch cc stretch Alkynes: lakshmi Aromatic Rings: c-h stretch cc stretch cc stretch Alcohols, Phenols: (Note: Phenols must have aromatic. Successfully reported this slideshow. Ftir lab Report, upcoming SlideShare, loading in 5, no downloads. No notes for slide. Schnell 1, experiment 7, ftir, margaret Schnell maschnell 00784786.
you should have a reading of 90-100. . Click the Stop button and then click the Scan button to start your scan. For a liquid, click the Scan button to start your scan. To label peaks, click on the peaks icon to automatically label your peaks. . Clicking a second time removes the labels. .
to label peaks that are still unlabeled, click on the vertical cursor icon, Vcursr, then drag the green line over the peak and double click. . double click on the green line to remove the line. To add text to your spectrum, click on the text (ABC) icon. . you have control of the font, and you can drag the text to a new position after it is written. save your spectrum to your usb flash drive. Under Edit, select Copy. Open the paint program (if it isnt already open) and Paste in your spectrum.
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The Spectrum One Scan and Instrument Setup window will open. . Choose the sample tab and enter a filename for your sample in the name line. . Fill in the description and comments as you choose. . Then click the Apply button. If you have a liquid, go. For a solid, click on the monitor icon (it looks like a fuel gauge) in the upper left corner of the window. . Then choose the sample icon (the middle of the three blue-ringed icons) and adjust the pressure by turning the knurled knob on the pressure arm. . you will see dream a green bar appear in the force gauge area. . Adjust the pressure until the green bar almost fills the window. .
wait until the scan finishes. . When the scan is complete, you may be asked if you want to overwrite the old background scan. . Click the delete icon to clear the spectrum window. . The background scan is not lost, just stored! Run a spectrum of your sample. Place aatankwad a small quantity of your sample on the center of the sample plate. . Swing the pressure arm over the sample and adjust until it touches the sample. . do not apply pressure yet. Choose Scan from the Instrument menu drop down list.
name background for, name. . Next click on the Scan tab and, under Options in the middle of the page, select Background as the Scan type. . All other settings can be left with their default values. Click the Apply button and then the Scan button. . The window will refresh, and soon you will see your background scan as it is running. . A bar in the lower left corner of the screen shows the progress of the scan. .
Press Return or click. The program will open and check the hardware. . Then you will see a message, which is titled Accessory ready Check. . It should say system ready for Use. . you may click the. If you are not the first user and there is a spectrum already displayed, click on the. Delete icon to clear the window for you and skip to step 4 below. Run a background spectrum. Make sure the sample area is clean and empty and.
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Infrared Spectroscopy (ft-ir infrared spectroscopy is a technique used to identify various functional groups in unknown substances through the identification of different tree covalent bonds that are present in the compound. By identifying the different covalent bonds that are present in a compound, you can establish the types of functional groups present. By comparing the absorptions seen in an experimental spectrum to the literature absorptions of various functional groups, you can determine a list of possible identities for the bonds present. The web tutorial, infrared Spectroscopy and Organic Functional Groups has more information. Procedure, chem 211 students may run ir spectra only during their regularly scheduled laboratory time. If the software is not already running, double click on the, spectrum icon to start the acquisition program. . When prompted, log in as chem212 with the password org212. The instrument. do not activate ir assistant. .