All-Solid-State Reference Electrode with Heterogeneous Membrane

Novel reference electrodes with a solid contact coated by a heterogeneous polymer membrane are described. The electrodes are obtained using Ag nanoparticles, AgBr, KBr suspended in tetrahydrofuran solution of PVC and DOS and deposited on Ag substrate, or another substrate covered with Ag, by drop casting. After a short period of soaking in a KBr solution, stable and reproducible formal potentials of -157 +/- 2 mV (vs Ag/AgCl/3 M KCl) were observed, and the solid-contact reference electrodes were ready to use. It is shown that the described reference electrodes are relatively insensitive to the changes in the sample matrix, the concentrations of ions, the pH and the redox potential. These electrodes can also be fabricated in miniaturized form, and thus used to produce miniaturized multielectrode probes.