Measuring a Reaction Rate- Experiment C

Start up procedure

• Make sure that the SpectroVis Plus Spectrophotometer is connected to USB port

· Go to “Start”, “All programs”. Chemistry Applications”, and then click “Logger Pro”

Choose the Settings

· Click on “Experiment” and then click “Data Collection…”

· Choose the following options in the dialog box that appears, and then click “Done”

· To choose the correct wavelength settings click on the “Configure Spectrometer” button

· Choose the following options in the dialog box that appears and then click “ok”

Calibrating the Spectrophotometer

· Click on “Experiment” and then click “calibrate; spectrometer:1”

· To make the blank add 0.5mL DMSO and 2.5mL Papain to a clean and dry cuvette. Place parafilm on top and invert four times, then place the blank in the sample holder

· Click “Finish calibration” in the calibration dialog box

· Once calibrated click “ok” and remove the cuvette from the sample holder

Collect Absorbance Values and Generate a Time vs. Absorbance Graph

· In a clean and dry test tube add 2.5mL Papain

· In that same test tube add 0.5mL of either 0.0025M BAPNA or 0.0050M BAPNA

· Place parafilm on top and invert the test tube four times

· Transfer the contents of the test tube into a clean and dry cuvette so that it is 3/4^th full

· Wipe the outside of the cuvette with a kimwipe and place in the sample holder

· Click “collect” . It should take no longer than 10 seconds to start collecting data from the time the BAPNA is added to the test tube containing the Papain

· Wait for the program to automatically stop at 50 seconds

· Click “linear fit”  , title, save and print the graph

· The graph should look similar to the one shown below

Collect Absorbance Spectra of the Final Product

• With the cuvette still in the sample holder, click “Experiment” and then click “Data Collection…”

• Choose the following options in the dialog box that appears then click “Done”

• Change the x-axis so that it ranges from 300nm to 800nm
• Left click on the y-axis and choose “Absorbance”
• Click “collect”  and wait for the spectra to appear
• Click “stop”
• Title, save and print the graph
• The above procedures can be repeated for the second molarity of BAPNA or you can obtain a graph from another group