Water chemistry of the water-steam cycle is crucial for maintaining plant reliability and for ensuring optimal plant operational conditions. Impurities such as corrosion products in ionic, colloidal, or oxide forms are ubiquitous in feedwater, condensate, and reactor coolant. This application shows the determination of sub-ppb levels of Cu, Ni, Zn and standard cations (e.g., Na +, NH 4 +, Mg 2+, Ca 2+) in the water-steam cycle of a BWR.