that of a glucose standard. This system can be constructed rapidly, and it is inexpensive. The amplifier that reads out the current from the working electrode costs less than $30 for off- the-shelf components. In combination with a data-logging system, we visualized the dynamic signals on a computer monitor. Data logging can also be accomplished with a low-cost hand-held multimeter. We believe that, in addition to being appropriate for use in the clinical laboratory, the system has characteristics (simplicity; ruggedness; low cost; adaptability for battery operation, if required) needed for certain diagnostic applications in developing countries; for home healthcare settings; and for applications in, for example, water and food quality, veterinary medicine, and environmental monitoring. This system has the potential to be less expensive in repetitive
analyses than many other currently used systems because the electrode surface is cleaned after each use by the continuous flow of buffer. Disposable components are therefore not necessary. The ease of construction and low cost also make the system attractive for use in education and training in analytical chemistry.