A comparison of microsecond vs. millisecond dwell times on particle number concentration measurements by single particle ICPMS

With the growing popularity of nanomaterials in a wide variety of products and processes, the need to measure and characterize these materials has also grown. For metallic or metal-containing engineered nanoparticles (NPs), single particle ICP-MS (SP-ICP-MS) has been developed and is growing in popularity due to its ability to rapidly detect and characterize a large number of particles, determine particle size and size distributions, the particle number concentration in a sample, and the elemental mass concentration of both dissolved and particulate species. SP-ICP-MS has been applied to a wide variety of sample types1-5, demonstrating its versatility. A key variable in SP-ICP-MS, which must be applied correctly for accurate measurement of particle concentration, is the dwell time of the ICP-MS. Although this topic has been discussed previously6,7, this work will focus on direct comparisons of results using both microsecond and millisecond dwell times. Since a detailed version of this work is available8, only a brief description will be given here