revised 8/27/07

Spectra/Data Manipulation Practice

Objectives

·    Use a cannual needle an inert atmosphere line to dispense and air-free sample.

·    Learn to operate the UV-vis, ATR IR, and EPR spectrometers

·    Practice saving, exporting, and incorporating data into Excel format

 

Procedural

suggestions

UV-vis:  Cannual transfer the green food dye into a cuvette.  Record the UV-visible spectrum.  Save the spectrum with an appropriate file name in your particular folder.  On a floppy disk or flash drive, save your green food dye spectrum as a .csv file.

 

                    blue and yellow food dye spectra (Abs vs wavelength)          

 

ATR IR:  Record the IR spectrum of solid [Co(NH3)5Cl]Cl2 using our ATR attachment.  Save the spectrum with an appropriate file name in your particular folder.  On a floppy disk or flash drive, save your spectrum as a .csv file.

 

EPR: Record the spectrum of the DPPH(s) standard.  Save the spectrum with an appropriate file name in your folder.  To be readable in spreadsheet formats, a program is used to convert the binary data file to ASCII text format.  This has been done for you in the following linked spectrum.

 

                   dpph EPR spectrum in Excel format

 

Data files must be saved in a clearly labeled folder with your name.  DO NOT save data files to the desktop; these will be regularly deleted.

 

 

Aq. reagents

green food dye

yellow food dye

blue food dye

 

Solid for IR

[Co(NH3)5Cl]Cl2

 

                                                                    

Organics

dpph (stable free radical)

Specialty equipment

·  EPR spectrometer

·  FTIR spectrometer w/ ATR attachment

·  UV-visible spectrometer

·  Cannual syringe needle, inert atmosphere line

·  cuvette

 

 

Items to include in your submitted

work

·    All work must be generated electronically, including captions, figures, and any annotations.  One effective way to do this is to prepare graphs in Excel and then paste them as figures in Powerpoint.  Here they can be scaled to fill the paper and clean captions and annotations can be added.

·    Plot the green food dye spectrum along with the blue and yellow food dye spectra downloaded from the above.  Present these data in a clear figure using spreadsheet software (Excel or similar) so as to most effectively  illustrate the fact the green food dye is in fact a mixture of blue and yellow dyes. 

·    Plot the IR spectrum of [Co(NH3)5Cl]Cl2.  Use your knowledge of organic functional groups and assign at least one peak in the spectrum.

·    Plot the EPR spectrum of dpph.  Just as in NMR, the y-axis is intensity in arbitrary units.

·    Specifics required for all plotted spectra: 
Include appropriate figure captions (do not use the chart title feature of Excel)
Label axes accordingly
Scale the figure so as to fill the entire page with the most important feature(s) in the spectrum