Over the last 25 years ICP-OES spectrometers, also known as ICP-AES or ICP plasma spectrometers, have become an indispensable tool for chemical elemental analysis. Optical emission spectrometers with inductively coupled plasma (ICP plasma) excitation sources offer ease of use, high sensitivity and precision and relative freedom from interferences. ICP-OES systems have now become the analytical method of choice for a wide range of applications.