Resumen de Using a Diode Laser Pointer to Count Drops and Automate Titration Systems
Paul J. Ogren, Steve Nelson, Ian Henry
An inexpensive Class 3a diode laser pointer is used to construct a simple system for recording drops falling from a buret. The drop signal is recorded together with one or more measurement signals by a LabVIEW-based programmable interfacing system. A standard buret is converted to a Mariotte buret to provide a constant drop-addition rate. Recalibration of the modified buret scale allows the titration program to convert number of drops to milliliters of titrant. The system is used to provide introductory experiences with automation and interfacing in analytical or physical chemistry. Examples of such uses are provided briefly in the article and are described more fully in the online documentation. A brief review of safety issues surrounding the use of diode laser pointers also is provided.
