NMSU: Cary 100

New Mexico State University

College of Arts and Sciences

Department of Chemistry and Biochemistry

Scan Procedure: Cary 100 -- UV and Visible Spectrophotometer

The INBRE laboratory has a UV and Visible spectrometer. The Cary 100 is a double beam, dual chopper, recording spectrophotometer controlled by a computer operating under Windows 2000, and running Varian's WinUV software. The instrument features, with using 1-cm cells are described.
I. Obtaining a UV-Visible Spectrum with the Cary 100 -- Scan
1. Turn on the instrument, its computer, and monitor. Normally the computer is not turned off. Use the proper login name and password to enter Windows 2000. Wait until the Windows 2000 desktop appears. Enter an official login name and professors name and department, if the department is not Chemistry and Biochemistry, into the instrument log
2. On the desktop, find the Icon for Cary WinUV and double click it. In the Cary WinUV window, select Scan and double click it to begin your instrument session. The Scan screen appears, with a menu across the top with a secondary row of buttons. Move the cursor onto each button (but don't click), wait a moment, and see what each button does.
3. Open the scan method file for this experiment as follows: File:Open Method. In the folder C:Varian\Cary WinUV\Chemistry\Method, find and open the file Simple_Scan. This file contains most of the proper initial settings for simple experiment. Change any of these settings by using the Setup button on the Scan screen.
4. Click Setup. The setup screen appears. This are actually several screens, each reachable by tabs at the top. Confirm or change to the Tab settings:
5. Click OK to return to the Scan screen.
6. Fill a clean quartz sample cell about 2/3 full with distilled water or solvent as a blank. Place the blank in the sample compartment with its clear sides facing left and right (a frosted side towards you). Close the spectrometer lid.

Caution: Do not spill solvents inside to cell compartment. Report any spills.

Handle the quartz cells carefully, see special handling instructions.

7. Click Zero to set the absorbance to approximately 0.00 absorbance units.
8. Click Baseline. If your water-filled cell is in place, click OK. The instrument runs a baseline spectrum, but does not display it. The instrument will subtract this baseline spectrum from each subsequent spectrum during your session. Wait until the base line is complete, traffic light is green.
9. Remove the sample cell, empty it, and refill it with another mixed sample. Place the cell in the sample compartment and close the lid.
10. Click Zero. Click Start (traffic light) to begin the scan. The Cary requests a brief sample name or number (preferred), which will be displayed on the scan. The spectrum appears in the upper half of the screen, followed by calculation of peak positions and intensities (absorbance) and generation of a report in the lower half of the screen.
11. If peak are too large or too small, click the Scale Graph button (two crossed rulers) at the top of the window to expand or contract the scan to fit the graphic area. Dilute the sample with solvent if the peak is not on screen and run another scan. Number each scan in sequence.
12. When you have a satisfactory scan, click the Trace (Scan) Preferences button () and uncheck all scans (traces) except what is to be printed. Click OK. Only one scan is visible.
13. When more than one scan is present, click Clear Report to remove all trace reports,and then click Recalculate to rewrite a report for this scan.
14. Look over the report information. Use the menu command Edit: Edit Report, and edit as required. Click anywhere off the report to exit the edit mode.
15. Click Print, if the report is satisfactory. Click OK on the print dialog.
16)Save it as follows, if it will be used in the future:
      a) Click Trace Preferences and redisplay (check) all traces. Click OK.
      b) File: Save Data. Set the file type to Batch and give your file a name.
         (A batch file includes all visible traces, the report, and the method settings.)
      c) Navigate to put the file into C:Varian\Cary WinUV\Chemistry\Spectra. Click OK to save.
      d) Data may also be saved to a 3 ½" floppy disk and processed with ACD software.
16. File: Exit to end your instrument session. Leave the cells and the instrument area CLEAN.

Tips for Cary 100

Additional information on File types and their applications is shown by the type of extensions.

Procedures for simple measurement of absorption and kinetics, are also described:

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