Ion-selective electrodes (ISEs) are used in a wide variety of applications for determining the concentrations of various ions in aqueous solutions. When compared to many other analytical techniques, ISEs are relatively inexpensive, simple to use, and have an extremely wide range of applications and concentrations. In recent reports, cytotoxicity of silver nanoparticles (AgNPs) showed that AgNPs were ionized in the cells and led to causing cell-death. Thus, the measurement of silver ions in aqueous phase is important. In this work, several sodium and potassium salts were considered as ionic-strength adjusters (ISA) and were used in the calibration step to enhance sensitivity of detection the target ion. The result showed that potassium iodine (0.05M KI) acted as a very effective ISA, compared to conventional ISA (5M NaNO3).