Ca2+-selective electrodes: a novel PVC-gelled neutral carrier mixture compared with other currently available sensors

The great importance of cytoplasmic free Ca2+ in regulating cellular function has stimulated the development of several more-or-less calcium-selective sensor systems for microelectrodes. The known formulations each have serious deficiencies, particularly in fine microelectrodes. We have developed a new sensor which gives distinctly improved performance in submicron tips. This sensor combines the widely used neutral carrier ETH1001 (Ammann et al., 1979) with an intensely hydrophobic salt into a poly(vinyl-chloride) gel. This study compares the calibration responses of the various sensor systems under a uniform set of experimental conditions.