Nitric acid is widely used throughout the semiconductor and electronics industry. Various purity grades are required depending on the application and the intended use. For this reason, the semiconductor industry has required ever-lower detection of a broad range of impurities, including non-metallic elements, in nitric acid solutions in order to meet manufacturing requirements.
Due to the presence of complex spectral interferences resulting from plasma gases and the sample matrix, low-ppt quantification of non-metallic elements in dilute nitric acid can be challenging using conventional ICP-MS. This issue is easily addressed with an ICP-MS system that not only mass filters the ions before they enter the collision-reaction cell but also controls the reaction in the cell, a feature only available in quadrupole cells. This works describes a mixed-mode method to determine detection limits and background equivalent concentrations of non-metallic impurities in a dilute nitric acid solution leveraging the unique capabilities of the NexION® 5000 Multi-Quadrupole ICP-MS.