Silver nanoparticle characterization using single particle ICP-MS (SP-ICP-MS) and asymmetrical flow field flow fractionation ICP-MS (AF4-ICP-MS)
Journal of Analytical Atomic Spectrometry
Figure S-1: Here, we relate pulse height to nanoparticle size. The ICP-MS is a mass-based technique where particle size is determined by relating the pulse intensity to an elemental mass. Following the figure above, as in traditional ICP-MS analysis, the first step in this process is to create a dissolved standard calibration curve. This relates the ICP-MS detector signal intensity to the concentration of the analyte entering the plasma. The next step is to determine the relationship between
... tionship between the concentration of the dissolved analyte and the total analyte mass (m p ) that enters the plasma during each dwell time. This relationship between analyte concentration and the mass observed per event is mass flux, which is highly dependent on the transport efficiency (η n ). The transport efficiency must be calculated for each instrument and under the given run conditions for the mass flux to be accurate. In this way, the mass flux calibration curve relates signal intensity (counts/event) to a total mass transported into the plasma in a given dwell time. Finally, the intensity of each individual pulse can then be transformed using the mass flux calibration curve to determine the particle mass. The ionization efficiency of the NP is presumed to be 1 (particles are 100 percent ionized) in most circumstances.