Cobalt alloys are commonly used in applications that require high resistance to temperature and corrosion. As such, cobalt is frequently used in turbines, engines, and prosthetic implants. Cobalt is also used for the production of lithium-ion batteries as a cathode material, and as a catalyst in other industrial applications. The fast, accurate determination of cobalt with a copper ion-selective electrode (Cu ISE) and Cu-EDTA complex as an indicator is described in this Application Note.