Solid-state ion-selective electrode arrays

Variable pressure scanning electron microscopy is demonstrated to be a powe rful method for directly studying swelling processes occurring during condi tioning of PVC-membrane ion-selective electrodes containing a salt-doped hy drogel layer between the PVC and the internal Ag/AgCl reference electrode. Using an in-house developed virtual instrument interface and a portable PC fitted with a PCMCIA data acquisition card, it is relatively easy to adapt arrays manufactured for blood-gas analysis for other applications which inv olve the determination of mixtures of inorganic ions. The simultaneous anal ysis of sodium and chloride over concentration ranges associated with the d iagnosis of cystic fibrosis (CF) in sweat is demonstrated as an example.