Analyze the absorbance of a solution

Measure the wavelengths of light a solution absorbs and transmits.

Note

For a more detailed tutorial, see the sample Analyzing the absorption spectrum of leaves experiment. Classroom-ready experiments are also available in the PASCO Experiment Library.

Procedure

1. Prepare the samples for analysis.

   1. Fill the cuvettes ¾ full with the sample solutions and cap.

   2. Prepare a reference solution by filling one cuvette ¾ full with the solvent used to make the sample solutions.

      Note

      Handle the cuvettes only by the lined sides to avoid getting fingerprints on the smooth sides.

2. Calibrate the spectrometer.

   1. Select the Analyze Solution page .
   2. Cover the spectrometer to block ambient light, then click .
   3. Insert the reference solution into the spectrometer, then click .
3. Collect data.
   1. Insert a sample into the spectrometer, then click Record .
   2. Use the Tools to adjust the smoothing and number of scans to average as needed.
   3. Click Stop to end data recording when you are satisfied with the results.
4. Analyze the data.
   1. Click and use the Coordinates tool to locate the peak(s) for each sample.
   2. Use the other graph tools as needed to perform further analysis.

Classroom-ready experiments

Plant Pigments

Students analyze spinach pigments and chloroplasts using paper chromatography, a colorimeter, and a spectrometer to understand how plants capture light for photosynthesis.

Chemical Equilibrium

Students use the results of a spectrometer and a temperature sensor to control the direction of a reversible chemical reaction.