Schematic diagram of the apparatus Reactant solutions are forced from large reservoirs into a T-shaped chamber, where they mix completely in less than 1 millisecond. The reacting mixture then travels down a long capillary tube. The product of the reaction is intensely colored and strongly absorbs a characteristic wavelength of light. Product concentration rises as the mixture moves along the tube. Seven light sensors placed at fixed positions along the tube monitor the increase in concentration.
Monochromatic light is passed through the capillary at each position using a fiber-optic cable.
A flow rate sensor allows the position of each of the spectrophotometers to be associated with a reaction time. If one exists, a new run is started. Otherwise, the system is flushed and the valves are closed to avoid unnecessary waste of reagent solutions. The camera view includes the reservoir manometer and a digital thermometer, so it is used for data collection as well as for helping students monitor the progress of the reaction. The Webcam is attached to a second PC to avoid contention.