Colorimeter method

  1. Prepare a range of samples of different concentrations of the required solutions.

  2. Calibrate the colorimeter using the appropriate filter and a blank solution.

  3. Record the absorbance of each solution of known concentration.

  4. Draw a calibration curve of absorbency against concentration.

  5. Place the reaction mixture in the colorimeter and record the absorbance at different times.

  6. Use the calibration curve to covert absorbance to concentration and plot a graph of concentration against time. A gradient of a tangent at any concentration on the graph gives the rate of concentration.