The location of a collision/reaction cell (CRC) in-between two quadrupole filters in tandem ICP-mass spectrometry (ICP-MS/MS) provides exceptional capabilities for avoiding spectral interference. This project aims at extending the application range and improving accuracy and precision by (i) developing an approach for multi-element analysis based on the use of NH3 as a “universal” reaction gas, (ii) investigating the optimum choice of an internal standard and (iii) developing methods for interference-free characterization of engineered nanoparticles using single particle ICP-MS/MS.