TY - JOUR A1 - Schmidt, Benita A1 - Pergantis, S. A. A1 - Esteban-Fernández, Diego A1 - Jakubowski, Norbert A1 - Günther, D. T1 - Investigation of a combined microdroplet generator and pneumatic nebulization system for rapid quantitative determination of metal-containing nanoparticles using ICP-MS N2 - In this work, a routinely applicable approach is presented to characterize metal NPs. Individual droplets generated from a microdroplet generator (MDG) were merged into an aerosol generated by a pneumatic nebulizer (PN) and introduced into an ICPMS. The MDG offers high transport efficiency of individual and discrete droplets and was therefore used to establish a calibration function for mass quantification of NPs which were introduced through the PN following the single particle procedure as described elsewhere. The major advantages of such a combined configuration include fast processing of large sample volumes, fast exchanges of different sample matrixes, and the calibration of the NP signal using traceable elemental standards, thus avoiding the need to use NP reference materials or other, not always thoroughly characterized, commercially available NPs. The transport efficiency of the sample introduction is calculated based on the fact that 100% of the calibrant reaches the plasma through the MDG, whereas for the PN a NP suspension containing a known number concentration is used. Alternatively, bulk analysis of the NP material allows transport efficiency determination without any additional information from reference NPs. With this method, we could determine the size of standard silver NPs at 60.4 ± 1.0 nm and 80.0 ± 1.4 nm, respectively, which agrees with the size ranges given by the supplier (60.8 ± 6.6 nm and 79.8 ± 5.4 nm). Furthermore, we were also able to determine the NPs number concentration of the sample (Ag/Au) with a deviation of 3.2% the expected value. KW - Nanoparticles KW - ICP-MS KW - Microdroplet generator PY - 2015 DO - https://doi.org/10.1021/acs.analchem.5b01604 SN - 0003-2700 SN - 1520-6882 VL - 87 IS - 17 SP - 8687 EP - 8694 PB - American Chemical Society CY - Washington, DC AN - OPUS4-34803 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hendriks, L. A1 - Ramkorun-Schmidt, Benita A1 - Grundlach-Graham, A. A1 - Koch, J. A1 - Grass, R. N. A1 - Jakubowski, Norbert A1 - Günther, D. T1 - Single-particle ICP-MS with online microdroplet calibration: toward matrix independent nanoparticle sizing N2 - Single-particle inductively coupled plasma mass spectrometry (sp-ICP-MS) has become an effective tool for the detection and quantification of inorganic nanoparticles (NPs). While sizing of NPs suspended in water is relatively straightforward by sp-ICP-MS, accurate mass quantification of NPs in complex media, such as consumer products and natural systems still remains a challenge. When NPs are suspended in a complex medium, the matrix may affect the analyte sensitivity and lead to inaccurate NP sizing. Here, we investigate the use of an online microdroplet calibration system to size NPs in a single step. In this setup, microdroplets—which are used as the calibrant to determine elemental sensitivities—and nebulized NP-containing solutions are introduced concurrently into the ICP via a dual-inlet sample introduction system. Because calibrant microdroplets and analyte NPs experience the same plasma conditions, both the microdroplets and the NPs are subjected to the same matrix-related signal enhancement or suppression. In this way, the microdroplet calibration standards are automatically matrix matched with the NP-containing solution. The online microdroplet calibration system is combined with an ICP-TOFMS instrument for simultaneous measurement of multiple elements in microdroplets and NPs. We investigate the ability of online microdroplet calibration to compensate for matrix effects through a series of experiments, in which Ag and Au NPs are measured with variable plasma-sampling positions, varying concentrations of HCl and HNO3, varying concentrations of single element solutions, and high concentrations of a salt matrix, i.e. phosphate buffered saline (PBS). Through these experiments, we demonstrate that the online microdroplet calibration strategy provides a matrix-independent mass quantification of analyte NPs in the presence of several established types of matrix effects, including acid effects, space-charge effects, and ionisation suppression. In results presented here, we focus on the size determination of the NPs. KW - Nanoparticle KW - ICP-MS KW - Calibration PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-477589 DO - https://doi.org/10.1039/c8ja00397a SN - 0267-9477 VL - 34 IS - 4 SP - 716 EP - 728 PB - Royal Society of Chemistry CY - London AN - OPUS4-47758 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -