CHE 450G: Practical Inorganic Chemistry

U of KY Dept of Chemistry

Shimadzu UV-3101PC UV-VIS Instructions

This handout explains how to use the Shimadzu UV-3101PC UV-VIS NIR found in CP-106C. This is a research instrument, so please be exceedingly careful in its use. Follow these instructions EXACTLY. You will use this instrument to obtain UV-VIS spectra for Szafran #28.

[Kinetics]   [Exporting Data]   [Manipulating Data]

Acquiring Simple UV-VIS spectra

1. Sign in on the logbook.

2. On the computer, you should see a Windows desktop. Double click on the Shimadzu directory if it is not already open. In the Shimadzu directory, double click on the UVPC icon.

3. A good set of parameters for routine use has already been saved. To load them from the UVPC program, go to the Configure menu and select Load Parameters.... Select the CHE450.CFG file, open it and then exit.

4. Open the sample compartment on the instrument. Place your sample cuvette in the front cell holder and your reference (usually distilled water) in the rear one. The little black covers go on top of your cuvettes. Close the sample compartment door.

5. Click on the Start button. Your scan will automatically acquire.

6. When the run is completed you will be prompted for a filename. Use your initials and notebook page number such as RT154b. You are limited to 8 DOS-compliant characters for a file name.

7. Go to the Presentation menu to set the display limits (x and y axis values) for your data. Then use the Plot selection to send your printout to the printer. If you would like to take a copy of your data home with you, see the instructions for exporting data below.

8. If you want to plot more than one spectrum on a single plot, go to the File menu and select Open.... Select your first spectrum, hit the Open button and then repeat for to add additional spectra. Press the Exit key to work with your data.
   If you wish to delete specta from a multiple spectrum plot go to the File menu, select Channel and Erase Channel. You can delete one or all of the spectra from the plot.

9. Go to the Presentation menu and select either Set Limits... or Radar to display your plots. You can send your plots to the printer using the Plot command found under the Presentation menu. Make sure your plots come out in Landscape format, not Portrait.

10. Finishing up:
    • Remove your sample and reference from the sample compartment.
    • Clean up any spills or debris.
    • If nobody else will be using the instrument that day, turn off the lamp by going to the Configure menu and loading in the parameters called LITEOFF.CFG.
    • Quit the UVPC program, leaving the computer in Windows with the Shimadzu window open.

11. Sign out on the logbook. Note any problems etc.

[Simple Scan]   [Exporting Data]   [Manipulating Data]

Acquiring Kinetic Data

1. Sign in on the logbook.

2. If you will be performing a run below room temperature, you will need to purge the sample compartment with nitrogen during your run to prevent condensation water inside the instrument. Simply open the valve mounted on the wall behind the instrument and adjust the flow rate to provide a slow purge.

3. The instument should be on and running. First locate the TCC (Temperature) Controller, which is to the left of the instrument. If it is not on, turn it on (the switch is on the back).

   

4. Set your desired temperature by switching the toggle on the front panel to Off and turning the dial. Flip the toggle switch to On. The temperature controller will slowly change to the temperature you have selected. The temperature limits are 0 to +80 degrees C.

5. On the computer, you should see a Windows desktop. If it is not already open, double click on the Shimadzu directory. Once inside there, double click on the Kinetics icon.

6. The parameters you need for a simple run at one wavelength have already been saved. To load them from the Kinetics program, go to the Configure menu and select Load Parameters.... Select the CHE450.CFG file, open it and then exit.

7. Once the temperature controller has achieved its setpoint, open the sample compartment on the instrument. Place your CLEAN sample cuvette in the front cell holder and your reference (distilled water) in the rear one. The little black covers go on top of your cuvettes. Close the sample compartment door.

8. We will be scanning at 550 nm. We will want to take a full UV-VIS spectrum before and after the run and can do so using the Popup Scan button. The scan will be displayed as it is collected.

9. Use the Radar! selection in the Popup window to autoscale your spectrum once it is collected. Then use the Save... selection in the Popup window to save your spectrum. Use your initials and notebook page number such as RT154c. You are limited to 8 DOS-compliant characters for a file name.

10. Close the Popup window. Click on the Start button on the kinetics window. Nothing will happen because the kinetics program has been told to wait 10 minutes to permit your sample to come to thermal equilibrium.

11. Data will be collected 10 times per minute for 150 minutes. If you see that the curve has leveled out completely and is no longer changing, you can stop the run early by hitting the Stop button.

12. You will be prompted for a filename when your run stops. Use your initials and notebook page number such as RT154d. You are limited to 8 DOS-compliant characters for a file name.

13. Go to the Presentation menu to set the display limits (x and y axis values) for your data. Then use the Plot selection to send your printout to the printer. If you would like to take a copy of your data home with you, bring a formatted floppy disk with you and save a copy.

14. Perform an additional Popup scan of your sample after the run is over.

15. To plot your Popup scans on one plot, go to the File menu from the UV-PC program (not Kinetics) and select Open.... Select your first plot and hit the Open button and then repeat for your final plot. Press the Exit key to work with your data.

16. Go to the Presentation menu and select either Set Limits... or Radar to display your plots. You can send your plots to the printer using the Plot command found under the Presentation menu. Make sure your plots come out in Landscape format, not Portrait.

17. Finishing up:
    • Remove your sample and reference from the sample compartment.
    • Clean up any spills or debris.
    • Turn the toggle switch on the temperature controller to "Off" and switch off the power switch on the rear of the temperature controller.
    • If you were using a nitrogen purge, wait until the temperature has returned to room temperature and then be sure to close the nitrogen valve.
    • If nobody else will be using the instrument that day, turn off the lamp by going to the Configure menu and loading in the parameters called LITEOFF.CFG.
    • Quit the Kinetics program, leaving the computer in Windows with the Shimadzu window open.

Sign out on the logbook. Note any problems etc.

As always, be sure to report any problems to your TA immediately.

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Exporting Your Kinetic Data

1. In the Kinetics program, open the data file(s) you wish to export.

2. Go to the File menu, select Export and then ASCII Export.

3. You will be shown a list of the current "channels" -- i.e. list of currently loaded data. Use the checkboxes to select those you wish to export (or the All checkbox).

4. Well-written software would prompt you for a filename and tell you that it performed the task...this software doesn't. It just sends you back to the Kinetics screen without a dialog box. However, your ASCii data file is now in the directory c:\uvpc\export and has saved your data with the original filename except that it now ends in ".asc".

5. Put your floppy disk in the drive and then use the File Manager (found under Main in the Program Manager...makes you want a Mac, doesn't it?) to copy the file from the c:\uvpc\export directory to your disk in drive A. If you exported multiple files at once, each will have its own filename.

6. Use your favorite software and import the file as a comma-delimited text file. DO NOT use Microsoft Excel...it is not meant for plotting files with hundreds of data points and it doesn't handle time intervals properly.

[Simple Scan]   [Acquiring Data]   [Exporting Data]   [Top of Page]

Manipulating Exported Data in Cricket Graph

1. Start Cricket Graph by double clicking on it. Put your disk in the floppy drive.

2. Close the blank new window that will appear. Under the Options menu select Preferences and then Text File I/O.... Set the options as shown below:

   .

3. Under the File menu use Open... to open your data file. Cricket is very slow at opening large data files, so be patient. When you're done, you'll see your time in Column 1 and Absorbance in Column 2. You can feel free to rename these columns something useful like "Time (sec)" and "Absorbance".

4. Highlight all of Column 1 by clicking on the 1 at the top of the column. Under the Options Menu select Numeric Format... and then select Decimal as the format.

5. Your book says to plot ln(A - A_infinity). To do this, go to the Data menu and select Simple Math.... Make the changes indicated, where the value of K is the value for A_infinity (that part is up to you):

   

6. This has made every value in column 3 equal to the value of column 2 minus your A_infinity. To take the natural log, go to the Data menu and select Transform.... and enter these values:

   

7. If your ln values in column 4 have too many digits, adjust the numeric format like you did in step 4. Feel free to rename column 4 to something more appropriate.

8. From the Graph menu, select a New Graph and then a Line chart. You'll be asked what columns you wish to plot and what range of data you wish to plot. You decide. Hit OK and your plot will be displayed.

9. I'll let you figure out how to play with the colors, plot attributes etc. But here's three things you will want to do:
   1. Under the Graph menu, select Graph Attributes and then Plot Symbol. This pops up a dialog with several pulldown menus in it. Select the Symbol pulldown menu and pick the option that looks like an "N" (for none). This way, you won't have 1000 little squares plotting on top of each other. Hit OK.

   2. Under the Options menu, select Curve Fit.... In the popup dialog, select "Linear" under Method. This will then enable the other features in the dialog. Change the Coefficient Display pulldown menu to "r squared" and hit "OK".

   3. The linear best fit and r squared will be displayed. Click on this once to select it and then set its Numeric Format (as above) to "Scientific" and two or three decimal points.

10. You can make the plot look a lot nicer by changing the fonts, colors, line widths etc., but those things are pretty easy to figure out on your own. Good luck!

Manipulating Exported Data in TableCurve

TableCurve may be available on one of the Wintel boxes in the CHE 450G laboratory; you'll have to look and see.

The instructions here are specifically for Experiment #2 in Angelici, but the concept of how to use the software is the same for other tasks.

1. Under File select Import. When the import file window pops up the file types show ASCII (prn,dat,txt) which does not help our cause, so pull the pop-up menu down and select All Files.

2. From this point it is pretty easy because TableCurve will put the values into the X-Y editor in the X and Y columns for you with the appropriate number of significant figures.

3. To plot ln(A-A_inf) select Calculation from the TableCurve Editor screen and enter "ln(y-Ainf)" in the y column field. Hit OK. TableCurve will ask if you would like to apply the calculation. You do!

4. From this point the data can be treated exactly like it would be if it were entered by hand. NOTE Rob sez: "Use a linear fit. I could get an r-squared of 0.999 on any data set if I used a 12th order polynomial, but that doesn't mean it is the correct way to interpret the data!"

5. Unfortunately, as with all graphs drawn with TableCurve, what you see is most of the time you get. If someone knows how to change graph colors etc. I would like to know. The title and axis labels can be edited from the Review Curve Fit Screen by pressing the shortcut icon across the top of the screen that is sixth from the right.

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This page was last updated and is copyright 1996-2000 by Rob Toreki. All rights reserved.