Towards Automated and High-Throughput Quantitative Sizing and Isotopic Analysis of Nanoparticles via Single Particle-ICP-TOF-MS

Abstract

The work described herein assesses the ability to characterize gold nanoparticles (Au NPs) of 50 and 100 nm, as well as 60 nm silver shelled gold core nanospheres (Au/Ag NPs), for their mass, respective size, and isotopic composition in an automated and unattended fashion. Here, an innovative autosampler was employed to mix and transport the blanks, standards, and samples into a high-efficiency single particle (SP) introduction system for subsequent analysis by inductively coupled plasma–time of flight–mass spectrometry (ICP-TOF-MS). Optimized NP transport efficiency into the ICP-TOF-MS was determined to be >80%. This combination, SP-ICP-TOF-MS, allowed for high-throughput sample analysis. Specifically, 50 total samples (including blanks/standards) were analyzed over 8 h, to provide an accurate characterization of the NPs. This methodology was implemented over the course of 5 days to assess its long-term reproducibility. Impressively, the in-run and day-to-day variation of sample transport is assessed to be 3.54 and 9.52% relative standard deviation (%RSD), respectively. The determination of Au NP size and concentration was of <5% relative difference from the certified values over these time periods. Isotopic characterization of the 107Ag/109Ag particles (n = 132,630) over the course of the measurements was determined to be 1.0788 ± 0.0030 with high accuracy (0.23% relative difference) when compared to the multi-collector–ICP-MS determination.

Development of single-cell ICP-TOFMS to measure nanoplastics association with human cells

“…61 In a different study, the robustness and reproducibility of this autosampler was successfully demonstrated for nanoparticles analysis and holds great promises for high-throughput single-cell analysis. 62…”

“…Consequently, this facilitated assessment of the method, but we would envision that one would also be able to measure lower concentrations of nanoplastics (and their association with cells) should exposure concentrations be reduced. Furthermore, the strength of the method relies on its adaptability and its potential for automation through use of an autosampler allowing for unattended operation 62 and automated data processing, which together allow for the analysis of more cells and would facilitate capturing more infrequent nanoplastics/cells associations at reduced exposure concentrations.…”

Quantifying platinum binding on protein-functionalized magnetic microparticles using single particle-ICP-TOF-MS

“…An icpTOF R (TOFWERK AG, Thun, Switzerland) was integrated with a microFAST SC sample introduction system from Elemental Scientific Inc (ESI, Omaha, NE, USA) for high throughput analysis. 29 The operating conditions of the ICP-TOF-MS can be found in Table 1. The ICP-TOF-MS was operated in collision cell technology (CCT) mode using ultra high purity (99.999%) H 2 and He gases (Airgas, Radnor, Pa, USA) to remove ArO interferences at m / z 56 and 57.…”

“…The microFAST SC autosampler sequence was created as described previously 29 in a study characterizing nanoparticles. Briefly, the autosampler probe goes into the sample and mixes via high speed (3000 μL min −1 ) alternating pumping of the sample using a syringe pump.…”

“…23 Because of these advantages, SP-ICP-TOF-MS has been used for a wide range of applications over the past few years including environmental analysis, 24,25 investigation of interstellar particles, 26 detection of microplastics, 27,28 and both the detection and characterization of nanoparticles. 12,29,30 As an extension of SP-ICP-TOF-MS, the application of the technique to measure endogenous elements and/or metal tagged single cells has quickly become a growing field. 31–33 In order to quantify single particles and single cells, Pace et al developed a quantification method that relies on the use of nanoparticle standards to correlate calibration curves to particle signals for mass determination.…”