Lone Pine Analytical uses ICP-MS for trace metals analysis. The primary reason we use ICP-MS is because the Atomic Absorption (AA) and Optical Emission Spectroscopy (ICP-OES) are fraught with interferences from other elements, which will lead to false positives. Most mining labs use AA and ICP-OES, because they are much less expensive instruments as compared to ICP-MS. However, false positives for precious metals puts the customer is a very difficult position. Mining samples tend to have many other elements in a complex mixture. Elements present in the complex mixture may have 4+ optical emissions, where one or more can and will overlap with the emission lines of precious metals. For examples, Pb is an interference for Au. Mn is an interference for Rh. In order to avoid interferences from other elements, the instrument operator should analyze the concentration from three or more emission lines of each precious metal. The problem is the labs don't to this! 

We receive samples many times, where the customer says another lab found a high concentration of Au or Pt or Pd. Then, we will run the analysis with ICP-MS, a much more sensitive instrument and less fraught with interferences, and we find very low concentrations of precious metals. Again, this is a huge problem in the mining industry.