Can ultrafast single-particle analysis using ICP-MS affect the detection limit? Case study: Silver nanoparticles

Ultrafast measurement using dwell times below 100 μs down to 10 μs is a relatively new feature of single particle analysis using ICP-MS. In this study, we tested the effect of shorter dwell times on the particle size detection limit (D_d.l.). Decreasing dwell times below 100 μs did not lead to a statistically significant decrease in D_d.l. The particle size detection limit (quadrupole ICP-MS) of silver nanoparticles (NP) was estimated to be approx. 10-11 nm. Ag NPs close to D_d.l. were analysed. The 14-nm NPs showed low detection yield; only 5% of number of NPs estimated from transport efficiency was detected. The 20-nm NPs showed 44% detection yield; only in the case of 30-nm NPs did the number of detected NPs correspond to transport efficiency. It is obvious that near D_d.l. estimates of NP concentrations should be made with great caution.