This memorandum clarifies which version of Method 3050 to use based on the analysis technique. If inductively coupled plasma – atomic emission spectroscopy (ICP-AES) is used, HCl should be used in the acid digestion, following Method 3050A. If ICP-MS is used, no HCl should be used due to matrix interference, following Method 3050B. The memorandum also discusses the detection of silver and antimony by ICP-MS.You may need Adobe Reader to view files on this page. See EPA’s About PDF page to learn more.