TEST EQUIPMENT AND PROCEDURES
Electrode tests were conducted with a previously designed
automated test stand (fig. 1) that allowed simultaneous
sampling of electromotive force (EMF) data from the
15 ISE electrodes measured relative to the reference electrode.
A 16-channel circuit board equipped with LF356N
operational amplifiers (National Semiconductor, Santa
Clara, Cal.) was used for buffering the impedance of each
sensor. A Daqbook 200 data acquisition system (IOTech,
Cleveland, Ohio) was used to perform analog-to-digital
conversion and transfer data to a 400 MHz Pentium II