A prototype of a new inductively coupled plasma time-of-flight mass spectrometer providing temporally resolved, multi-element detection of short signals generated by single particles and droplets

Abstract

A prototype inductively coupled plasma time-of-flight mass spectrometer (ICPTOFMS) for time resolved measurements of transient signals in the microsecond regime is described in this work. Analytical figures of merit for the prototype are given for both liquid nebulization and single droplet introduction and are compared to a conventional quadrupole-based ICPMS using the same ICP source and vacuum interface.Quasi-simultaneous detection at a time resolution of 33 ms of the prototype ICPTOFMS allows multiisotope monitoring of short signals (200-500 ms duration) generated from individual droplets and particles. The capabilities of the instrument for the analysis of single nanoparticles are studied using microdroplets consisting of a multi-element standard solution and containing 114 nm Au particles. The detection efficiencies for Ag and Au, calculated from the response of individual droplets and particles, are similar to those of the quadrupole-based instrument and amount to 1.3 Â 10 À6 ions per atom and 3.1 Â 10 À6 ions per atom, respectively. The sizes of the smallest detectable Ag, Au and U metallic nanoparticles are estimated to be 46 nm, 32 nm and 22 nm, respectively. Furthermore, time shifts of the signals of different elements within single droplets were observed. These new results demonstrate the advantage of the temporal resolution of the instrument for studying processes taking place in the plasma on the ms-time scale.

Development of routines for simultaneous in situ chemical composition and stable Si isotope ratio analysis by femtosecond laser ablation inductively coupled plasma mass spectrometry

“…Pb 0.73% RSD, 10 µg kg -1 ) is not sufficient to resolve the sub-permil variations in stable metal and metalloid isotope systems. [22] Results shown by Ardelt and co-workers from a new Mattauch-Herzog ICP-MS are promising in terms of accuracy. [23] However integration times of 40 to 100 s for a single replicate are not appropriate for transient laser ablation signals, and the background spectra shown by Resano et al shows a large background elevation and depletion from the baseline, which could affect the elements of interest (e.g., Mg, Si and Fe).…”

Single Particle ICP-MS: Advances toward routine analysis of nanomaterials

“…This provides for an approach to measure spICP-MS sensitivity (counts/fg analyte element) without the need for nanoparticle standards of known size [36,73,74]. Monodisperse droplet generators typically produce droplets (30 to 60 μm in diameter, depending on the generator design and voltages applied) that are too large to be completely vaporized in the ICP under typical plasma conditions.…”

Inductively Coupled Plasma Zoom–Time-of-Flight Mass Spectrometry

“…The calculated detection limit (by Figure 3. (a) CEA-and (b) CMA-TOFMS mass spectra for lead that correspond to the data in Table 1. The baseline fluctuations in both traces are due to an impedance mismatch in the detection system that causes ringing [36,37,39]. However, when the zoom-TOFMS instrument is operated in the CMA zoom mode at a 43.5 kHz repetition rate, the LDR of the instrument is expanded.…”

“…Commercial single-reflectron ICP-TOFMS systems routinely produce mass resolution on the order of 1000-2500 for up to 1-m flight paths [36,37]. The current 35-cm geometry ICP-zoom-TOFMS system performs well within that resolution range for both operational modes.…”