Labs with heavy workloads – needing to measure many elements in many samples will need a fast inductively coupled plasma metals analysis technique like ICP-OES or ICP-MS.
When comparing the two techniques it’s important to realize that there is an overlap of the concentration ranges that ICP-OES and ICP-MS can measure. If all elements are consistently at concentrations above 10 ppb then ICP-OES is the best option. If you need to measure lower concentrations of some elements or you need to measure C, F, Cl, Br, or I then elemental analysis by ICP-MS is recommended. Even with ICP-MS, detection limits for C are poor, and F requires a specialized ICP-QQQ approach. The eBook “How to choose the right atomic spectroscopy technique” (linked at the bottom of this page) provides the details on which elements each technique can measure.
While ICP-OES metals analysis cannot measure concentrations of metals down to the parts-per-trillion levels that ICP-MS can, ICP-OES is often used for measurements that might previously have been done using flame AA.
Highly specialized applications that need to measure the radioactive elements Np, Pu, Am, or Ra or other very rare actinides elements (Ac, Bk, Cf, Cm, Pa, Po) will also require elemental analysis by ICP-MS.